Merge pull request 'restructure-config' (#8) from restructure-config into main

Reviewed-on: sashakoshka/tomo#8

artist/text.go

@@ -165,6 +165,7 @@ func (drawer *TextDrawer) LineHeight () (height fixed.Int26_6) {
 // have its maximum width set to the given width. This does not alter the
 // drawer's state.
 func (drawer *TextDrawer) ReccomendedHeightFor (width int) (height int) {
+	if drawer.face == nil { return }
 	if !drawer.layoutClean { drawer.recalculate() }
 	metrics := drawer.face.Metrics()
 	dot := fixed.Point26_6 { 0, metrics.Height }

backend.go

@@ -2,6 +2,8 @@ package tomo
 
 import "errors"
 import "git.tebibyte.media/sashakoshka/tomo/data"
+import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/elements"
 
 // Backend represents a connection to a display server, or something similar.
@@ -28,6 +30,12 @@ type Backend interface {
 
 	// Paste returns the data currently in the clipboard.
 	Paste (accept []data.Mime) (data.Data)
+	
+	// SetTheme sets the theme of all open windows.
+	SetTheme (theme.Theme)
+	
+	// SetConfig sets the configuration of all open windows.
+	SetConfig (config.Config)
 }
 
 // BackendFactory represents a function capable of constructing a backend

backends/x/window.go

@@ -8,6 +8,8 @@ import "github.com/jezek/xgbutil/xevent"
 import "github.com/jezek/xgbutil/xwindow"
 import "github.com/jezek/xgbutil/xgraphics"
 import "git.tebibyte.media/sashakoshka/tomo/input"
+import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
 import "git.tebibyte.media/sashakoshka/tomo/elements"
 
@@ -20,6 +22,9 @@ type Window struct {
 	onClose func ()
 	skipChildDrawCallback bool
 
+	theme  theme.Theme
+	config config.Config
+
 	metrics struct {
 		width  int
 		height int
@@ -70,6 +75,9 @@ func (backend *Backend) NewWindow (
 	xevent.MotionNotifyFun(window.handleMotionNotify).
 		Connect(backend.connection, window.xWindow.Id)
 
+	window.SetTheme(backend.theme)
+	window.SetConfig(backend.config)
+	
 	window.metrics.width  = width
 	window.metrics.height = height
 	window.childMinimumSizeChangeCallback(8, 8)
@@ -100,6 +108,12 @@ func (window *Window) Adopt (child elements.Element) {
 	
 	// adopt new child
 	window.child = child
+	if newChild, ok := child.(elements.Themeable); ok {
+		newChild.SetTheme(window.theme)
+	}
+	if newChild, ok := child.(elements.Configurable); ok {
+		newChild.SetConfig(window.config)
+	}
 	if newChild, ok := child.(elements.Flexible); ok {
 		newChild.OnFlexibleHeightChange(window.resizeChildToFit)
 	}
@@ -196,6 +210,20 @@ func (window *Window) OnClose (callback func ()) {
 	window.onClose = callback
 }
 
+func (window *Window) SetTheme (theme theme.Theme) {
+	window.theme = theme
+	if child, ok := window.child.(elements.Themeable); ok {
+		child.SetTheme(theme)
+	}
+}
+
+func (window *Window) SetConfig (config config.Config) {
+	window.config = config
+	if child, ok := window.child.(elements.Configurable); ok {
+		child.SetConfig(config)
+	}
+}
+
 func (window *Window) reallocateCanvas () {
 	window.canvas.Reallocate(window.metrics.width, window.metrics.height)
 

backends/x/x.go

@@ -2,6 +2,8 @@ package x
 
 import "git.tebibyte.media/sashakoshka/tomo"
 import "git.tebibyte.media/sashakoshka/tomo/data"
+import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 
 import "github.com/jezek/xgbutil"
 import "github.com/jezek/xgb/xproto"
@@ -25,6 +27,9 @@ type Backend struct {
 		hyper uint16
 	}
 
+	theme  theme.Theme
+	config config.Config
+
 	windows map[xproto.Window] *Window
 }
 
@@ -33,6 +38,8 @@ func NewBackend () (output tomo.Backend, err error) {
 	backend := &Backend {
 		windows: map[xproto.Window] *Window { },
 		doChannel: make(chan func (), 0),
+		theme:  theme.Default  { },
+		config: config.Default { },
 	}
 	
 	// connect to X
@@ -66,7 +73,11 @@ func (backend *Backend) Run () (err error) {
 // Stop gracefully closes the connection and stops the event loop.
 func (backend *Backend) Stop () {
 	backend.assert()
+	toClose := []*Window { }
 	for _, window := range backend.windows {
+		toClose = append(toClose, window)
+	}
+	for _, window := range toClose {
 		window.Close()
 	}
 	xevent.Quit(backend.connection)
@@ -95,6 +106,25 @@ func (backend *Backend) Paste (accept []data.Mime) (data data.Data) {
 	return
 }
 
+
+// SetTheme sets the theme of all open windows.
+func (backend *Backend) SetTheme (theme theme.Theme) {
+	backend.assert()
+	backend.theme = theme
+	for _, window := range backend.windows {
+		window.SetTheme(theme)
+	}
+}
+
+// SetConfig sets the configuration of all open windows.
+func (backend *Backend) SetConfig (config config.Config) {
+	backend.assert()
+	backend.config = config
+	for _, window := range backend.windows {
+		window.SetConfig(config)
+	}
+} 
+
 func (backend *Backend) assert () {
 	if backend == nil { panic("nil backend") }
 }

config/config.go

@@ -1,22 +1,93 @@
 package config
 
-// Padding returns the amount of internal padding elements should have. An
+// Config can return global configuration parameters.
-// element's inner content (such as text) should be inset by this amount,
+type Config interface {
-// in addition to the inset returned by the pattern of its background. When
+	// Padding returns the amount of internal padding elements should have.
-// using the aforementioned inset values to calculate the element's minimum size
+	// An element's inner content (such as text) should be inset by this
-// or the position and alignment of its content, all parameters in the
+	// amount, in addition to the inset returned by the pattern of its
-// PatternState should be unset except for Case.
+	// background.
-func Padding () int {
+	Padding () int
+	
+	// Margin returns how much space should be put in between elements.
+	Margin () int
+
+	// HandleWidth returns how large grab handles should typically be. This
+	// is important for accessibility reasons.
+	HandleWidth () int
+
+	// ScrollVelocity returns how many pixels should be scrolled every time
+	// a scroll button is pressed.
+	ScrollVelocity () int
+
+	// ThemePath returns the directory path to the theme.
+	ThemePath () string
+}
+
+// Default specifies default configuration values.
+type Default struct { }
+
+// Padding returns the default padding value.
+func (Default) Padding () int {
 	return 7
 }
 
-// Margin returns how much space should be put in between elements.
+// Margin returns the default margin value.
-func Margin () int {
+func (Default) Margin () int {
 	return 8
 }
 
-// HandleWidth returns how large grab handles should typically be. This is
+// HandleWidth returns the default handle width value.
-// important for accessibility reasons.
+func (Default) HandleWidth () int {
-func HandleWidth () int {
 	return 16
 }
+
+// ScrollVelocity returns the default scroll velocity value.
+func (Default) ScrollVelocity () int {
+	return 16
+}
+
+// ThemePath returns the default theme path.
+func (Default) ThemePath () (string) {
+	return ""
+}
+
+// Wrapped wraps a configuration and uses Default if it is nil.
+type Wrapped struct {
+	Config
+}
+
+// Padding returns the amount of internal padding elements should have.
+// An element's inner content (such as text) should be inset by this
+// amount, in addition to the inset returned by the pattern of its
+// background.
+func (wrapped Wrapped) Padding () int {
+	return wrapped.ensure().Padding()
+}
+
+// Margin returns how much space should be put in between elements.
+func (wrapped Wrapped) Margin () int {
+	return wrapped.ensure().Margin()
+}
+
+// HandleWidth returns how large grab handles should typically be. This
+// is important for accessibility reasons.
+func (wrapped Wrapped) HandleWidth () int {
+	return wrapped.ensure().HandleWidth()
+}
+
+// ScrollVelocity returns how many pixels should be scrolled every time
+// a scroll button is pressed.
+func (wrapped Wrapped) ScrollVelocity () int {
+	return wrapped.ensure().ScrollVelocity()
+}
+
+// ThemePath returns the directory path to the theme.
+func (wrapped Wrapped) ThemePath () string {
+	return wrapped.ensure().ThemePath()
+}
+
+func (wrapped Wrapped) ensure () (real Config) {
+	real = wrapped.Config
+	if real == nil { real = Default { } }
+	return
+}

config/parse.go

@@ -0,0 +1,9 @@
+package config
+
+import "io"
+
+// Parse parses one or more configuration files and returns them as a Config.
+func Parse (sources ...io.Reader) (config Config) {
+	// TODO
+	return Default { }
+}

dirs/dirs.go

@@ -0,0 +1,82 @@
+package dirs
+
+import "os"
+import "strings"
+import "path/filepath"
+
+var homeDirectory string
+var configHome    string
+var configDirs    []string
+var dataHome      string
+var dataDirs      []string
+var cacheHome     string
+
+func init () {
+	var err error
+	homeDirectory, err = os.UserHomeDir()
+	if err != nil {
+		panic("could not get user home directory: " + err.Error())
+	}
+
+	configHome = os.Getenv("XDG_CONFIG_HOME")
+	if configHome == "" {
+		configHome = filepath.Join(homeDirectory, "/.config/")
+	}
+	
+	configDirsString := os.Getenv("XDG_CONFIG_DIRS")
+	if configDirsString == "" {
+		configDirsString = "/etc/xdg/"
+	}
+	configDirs = append(strings.Split(configDirsString, ":"), configHome)
+
+	dataHome = os.Getenv("XDG_DATA_HOME")
+	if dataHome == "" {
+		dataHome = filepath.Join(homeDirectory, "/.local/share/")
+	}
+	
+	dataDirsString := os.Getenv("XDG_CONFIG_DIRS")
+	if dataDirsString == "" {
+		dataDirsString = "/usr/local/share/:/usr/share/"
+	}
+	configDirs = append(strings.Split(configDirsString, ":"), configHome)
+
+	cacheHome = os.Getenv("XDG_CACHE_HOME")
+	if cacheHome == "" {
+		cacheHome = filepath.Join(homeDirectory, "/.cache/")
+	}
+}
+
+// ConfigHome returns the path to the directory where user configuration files
+// should be stored.
+func ConfigHome (name string) (home string) {
+	return filepath.Join(configHome, name)
+}
+
+// ConfigDirs returns all paths where configuration files might exist.
+func ConfigDirs (name string) (dirs []string) {
+	dirs = make([]string, len(configDirs))
+	for index, dir := range configDirs {
+		dirs[index] = filepath.Join(dir, name)
+	}
+	return
+}
+
+// DataHome returns the path to the directory where user data should be stored.
+func DataHome (name string) (home string) {
+	return filepath.Join(dataHome, name)
+}
+
+// DataDirs returns all paths where data files might exist.
+func DataDirs (name string) (dirs []string) {
+	dirs = make([]string, len(dataDirs))
+	for index, dir := range dataDirs {
+		dirs[index] = filepath.Join(dir, name)
+	}
+	return
+}
+
+// CacheHome returns the path to the directory where user cache files should be
+// stored.
+func CacheHome (name string) (home string) {
+	return filepath.Join(cacheHome, name)
+}

elements/basic/button.go

@@ -3,11 +3,10 @@ package basicElements
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var buttonCase = theme.C("basic", "button")
-
 // Button is a clickable button.
 type Button struct {
 	*core.Core
@@ -19,21 +18,19 @@ type Button struct {
 	pressed bool
 	text    string
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onClick func ()
 }
 
 // NewButton creates a new button with the specified label text.
 func NewButton (text string) (element *Button) {
 	element = &Button { }
+	element.theme.Case = theme.C("basic", "button")
 	element.Core, element.core = core.NewCore(element.draw)
 	element.FocusableCore,
-	element.focusableControl = core.NewFocusableCore (func () {
+	element.focusableControl = core.NewFocusableCore(element.redo)
-		if element.core.HasImage () {
-			element.draw()
-			element.core.DamageAll()
-		}
-	})
-	element.drawer.SetFace(theme.FontFaceRegular())
 	element.SetText(text)
 	return
 }
@@ -43,19 +40,13 @@ func (element *Button) HandleMouseDown (x, y int, button input.Button) {
 	if !element.Focused() { element.Focus() }
 	if button != input.ButtonLeft { return }
 	element.pressed = true
-	if element.core.HasImage() {
+	element.redo()
-		element.draw()
-		element.core.DamageAll()
-	}
 }
 
 func (element *Button) HandleMouseUp (x, y int, button input.Button) {
 	if button != input.ButtonLeft { return }
 	element.pressed = false
-	if element.core.HasImage() {
+	element.redo()
-		element.draw()
-		element.core.DamageAll()
-	}
 
 	within := image.Point { x, y }.
 		In(element.Bounds())
@@ -73,20 +64,14 @@ func (element *Button) HandleKeyDown (key input.Key, modifiers input.Modifiers)
 	if !element.Enabled() { return }
 	if key == input.KeyEnter {
 		element.pressed = true
-		if element.core.HasImage() {
+		element.redo()
-			element.draw()
-			element.core.DamageAll()
-		}
 	}
 }
 
 func (element *Button) HandleKeyUp(key input.Key, modifiers input.Modifiers) {
 	if key == input.KeyEnter && element.pressed {
 		element.pressed = false
-		if element.core.HasImage() {
+		element.redo()
-			element.draw()
-			element.core.DamageAll()
-		}
 		if !element.Enabled() { return }
 		if element.onClick != nil {
 			element.onClick()
@@ -110,10 +95,36 @@ func (element *Button) SetText (text string) {
 
 	element.text = text
 	element.drawer.SetText([]rune(text))
+	element.updateMinimumSize()
+	element.redo()
+}
+
+// SetTheme sets the element's theme.
+func (element *Button) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.drawer.SetFace (element.theme.FontFace (
+		theme.FontStyleRegular,
+		theme.FontSizeNormal))
+	element.updateMinimumSize()
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *Button) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.updateMinimumSize()
+	element.redo()
+}
+
+func (element *Button) updateMinimumSize () {
 	textBounds := element.drawer.LayoutBounds()
-	_, inset := theme.ButtonPattern(theme.PatternState { Case: buttonCase })
+	minimumSize := textBounds.Inset(-element.config.Padding())
-	minimumSize := inset.Inverse().Apply(textBounds).Inset(-theme.Padding())
 	element.core.SetMinimumSize(minimumSize.Dx(), minimumSize.Dy())
+}
+
+func (element *Button) redo () {
 	if element.core.HasImage () {
 		element.draw()
 		element.core.DamageAll()
@@ -123,21 +134,20 @@ func (element *Button) SetText (text string) {
 func (element *Button) draw () {
 	bounds := element.Bounds()
 
-	pattern, inset := theme.ButtonPattern(theme.PatternState {
+	state := theme.PatternState {
-		Case: buttonCase,
 		Disabled: !element.Enabled(),
-		Focused: element.Focused(),
+		Focused:  element.Focused(),
 		Pressed:  element.pressed,
-	})
+	}
+
+	pattern := element.theme.Pattern(theme.PatternButton, state)
 
 	artist.FillRectangle(element, pattern, bounds)
 
-	innerBounds := inset.Apply(bounds)
-
 	textBounds := element.drawer.LayoutBounds()
 	offset := image.Point {
-		X: innerBounds.Min.X + (innerBounds.Dx() - textBounds.Dx()) / 2,
+		X: bounds.Min.X + (bounds.Dx() - textBounds.Dx()) / 2,
-		Y: innerBounds.Min.Y + (innerBounds.Dy() - textBounds.Dy()) / 2,
+		Y: bounds.Min.Y + (bounds.Dy() - textBounds.Dy()) / 2,
 	}
 
 	// account for the fact that the bounding rectangle will be shifted over
@@ -145,9 +155,10 @@ func (element *Button) draw () {
 	offset.Y -= textBounds.Min.Y
 	offset.X -= textBounds.Min.X
 
-	foreground, _ := theme.ForegroundPattern (theme.PatternState {
+	if element.pressed {
-		Case: buttonCase,
+		offset = offset.Add(element.theme.Sink(theme.PatternButton))
-		Disabled: !element.Enabled(),
+	}
-	})
+
+	foreground := element.theme.Pattern(theme.PatternForeground, state)
 	element.drawer.Draw(element, foreground, offset)
 }

elements/basic/checkbox.go

@@ -3,11 +3,10 @@ package basicElements
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var checkboxCase = theme.C("basic", "checkbox")
-
 // Checkbox is a toggle-able checkbox with a label.
 type Checkbox struct {
 	*core.Core
@@ -20,21 +19,19 @@ type Checkbox struct {
 	checked bool
 	text    string
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onToggle func ()
 }
 
 // NewCheckbox creates a new cbeckbox with the specified label text.
 func NewCheckbox (text string, checked bool) (element *Checkbox) {
 	element = &Checkbox { checked: checked }
+	element.theme.Case = theme.C("basic", "checkbox")
 	element.Core, element.core = core.NewCore(element.draw)
 	element.FocusableCore,
-	element.focusableControl = core.NewFocusableCore (func () {
+	element.focusableControl = core.NewFocusableCore(element.redo)
-		if element.core.HasImage () {
-			element.draw()
-			element.core.DamageAll()
-		}
-	})
-	element.drawer.SetFace(theme.FontFaceRegular())
 	element.SetText(text)
 	return
 }
@@ -116,16 +113,45 @@ func (element *Checkbox) SetText (text string) {
 
 	element.text = text
 	element.drawer.SetText([]rune(text))
-	textBounds := element.drawer.LayoutBounds()
+	element.updateMinimumSize()
 	
-	if text == "" {
+	if element.core.HasImage () {
+		element.draw()
+		element.core.DamageAll()
+	}
+}
+
+// SetTheme sets the element's theme.
+func (element *Checkbox) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.drawer.SetFace (element.theme.FontFace (
+		theme.FontStyleRegular,
+		theme.FontSizeNormal))
+	element.updateMinimumSize()
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *Checkbox) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.updateMinimumSize()
+	element.redo()
+}
+
+func (element *Checkbox) updateMinimumSize () {
+	textBounds := element.drawer.LayoutBounds()
+	if element.text == "" {
 		element.core.SetMinimumSize(textBounds.Dy(), textBounds.Dy())
 	} else {
 		element.core.SetMinimumSize (
-			textBounds.Dy() + theme.Padding() + textBounds.Dx(),
+			textBounds.Dy() + element.config.Padding() + textBounds.Dx(),
 			textBounds.Dy())
 	}
+}
 
+func (element *Checkbox) redo () {
 	if element.core.HasImage () {
 		element.draw()
 		element.core.DamageAll()
@@ -136,35 +162,28 @@ func (element *Checkbox) draw () {
 	bounds := element.Bounds()
 	boxBounds := image.Rect(0, 0, bounds.Dy(), bounds.Dy()).Add(bounds.Min)
 
-	backgroundPattern, _ := theme.BackgroundPattern(theme.PatternState {
+	state := theme.PatternState {
-		Case: checkboxCase,
-	})
-	artist.FillRectangle(element, backgroundPattern, bounds)
-
-	pattern, inset := theme.ButtonPattern(theme.PatternState {
-		Case: checkboxCase,
 		Disabled: !element.Enabled(),
 		Focused:  element.Focused(),
 		Pressed:  element.pressed,
-	})
+		On:       element.checked,
+	}
+
+	backgroundPattern := element.theme.Pattern (
+		theme.PatternBackground, state)
+	artist.FillRectangle(element, backgroundPattern, bounds)
+
+	pattern := element.theme.Pattern(theme.PatternButton, state)
 	artist.FillRectangle(element, pattern, boxBounds)
 
 	textBounds := element.drawer.LayoutBounds()
 	offset := bounds.Min.Add(image.Point {
-		X: bounds.Dy() + theme.Padding(),
+		X: bounds.Dy() + element.config.Padding(),
 	})
 
 	offset.Y -= textBounds.Min.Y
 	offset.X -= textBounds.Min.X
 
-	foreground, _ := theme.ForegroundPattern (theme.PatternState {
+	foreground := element.theme.Pattern(theme.PatternForeground, state)
-		Case: checkboxCase,
-		Disabled: !element.Enabled(),
-	})
 	element.drawer.Draw(element, foreground, offset)
-	
-	if element.checked {
-		checkBounds := inset.Apply(boxBounds).Inset(2)
-		artist.FillRectangle(element, foreground, checkBounds)
-	}
 }

elements/basic/container.go

@@ -3,14 +3,13 @@ package basicElements
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/layouts"
 import "git.tebibyte.media/sashakoshka/tomo/elements"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var containerCase = theme.C("basic", "container")
-
 // Container is an element capable of containg other elements, and arranging
 // them in a layout.
 type Container struct {
@@ -25,6 +24,9 @@ type Container struct {
 	focusable bool
 	flexible  bool
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onFocusRequest func () (granted bool)
 	onFocusMotionRequest func (input.KeynavDirection) (granted bool)
 	onFlexibleHeightChange func ()
@@ -33,6 +35,7 @@ type Container struct {
 // NewContainer creates a new container.
 func NewContainer (layout layouts.Layout) (element *Container) {
 	element = &Container { }
+	element.theme.Case = theme.C("basic", "container")
 	element.Core, element.core = core.NewCore(element.redoAll)
 	element.SetLayout(layout)
 	return
@@ -52,6 +55,12 @@ func (element *Container) SetLayout (layout layouts.Layout) {
 // whatever way is defined by the current layout.
 func (element *Container) Adopt (child elements.Element, expand bool) {
 	// set event handlers
+	if child0, ok := child.(elements.Themeable); ok {
+		child0.SetTheme(element.theme.Theme)
+	}
+	if child0, ok := child.(elements.Configurable); ok {
+		child0.SetConfig(element.config.Config)
+	}
 	child.OnDamage (func (region canvas.Canvas) {
 		element.core.DamageRegion(region.Bounds())
 	})
@@ -205,9 +214,9 @@ func (element *Container) redoAll () {
 
 	// draw a background
 	bounds := element.Bounds()
-	pattern, _ := theme.BackgroundPattern (theme.PatternState {
+	pattern := element.theme.Pattern (
-		Case: containerCase,
+		theme.PatternBackground,
-	})
+		theme.PatternState { })
 	artist.FillRectangle(element, pattern, bounds)
 
 	// cut our canvas up and give peices to child elements
@@ -216,6 +225,33 @@ func (element *Container) redoAll () {
 	}
 }
 
+
+// SetTheme sets the element's theme.
+func (element *Container) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	for _, child := range element.children {
+		if child0, ok := child.Element.(elements.Themeable); ok {
+			child0.SetTheme(element.theme.Theme)
+		}
+	}
+	element.updateMinimumSize()
+	element.redoAll()
+}
+
+// SetConfig sets the element's configuration.
+func (element *Container) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	for _, child := range element.children {
+		if child0, ok := child.Element.(elements.Configurable); ok {
+			child0.SetConfig(element.config)
+		}
+	}
+	element.updateMinimumSize()
+	element.redoAll()
+}
+
 func (element *Container) HandleMouseDown (x, y int, button input.Button) {
 	child, handlesMouse := element.ChildAt(image.Pt(x, y)).(elements.MouseTarget)
 	if !handlesMouse { return }
@@ -266,7 +302,7 @@ func (element *Container) HandleKeyUp (key input.Key, modifiers input.Modifiers)
 func (element *Container) FlexibleHeightFor (width int) (height int) {
 	return element.layout.FlexibleHeightFor (
 		element.children,
-		theme.Margin(), width)
+		element.config.Margin(), width)
 }
 
 func (element *Container) OnFlexibleHeightChange (callback func ()) {
@@ -469,15 +505,15 @@ func (element *Container) childFocusRequestCallback (
 
 func (element *Container) updateMinimumSize () {
 	width, height := element.layout.MinimumSize (
-		element.children, theme.Margin())
+		element.children, element.config.Margin())
 	if element.flexible {
 		height = element.layout.FlexibleHeightFor (
-			element.children, theme.Margin(), width)
+			element.children, element.config.Margin(), width)
 	}
 	element.core.SetMinimumSize(width, height)
 }
 
 func (element *Container) recalculate () {
 	element.layout.Arrange (
-		element.children, theme.Margin(), element.Bounds())
+		element.children, element.config.Margin(), element.Bounds())
 }

elements/basic/label.go

@@ -1,11 +1,10 @@
 package basicElements
 
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var labelCase = theme.C("basic", "label")
-
 // Label is a simple text box.
 type Label struct {
 	*core.Core
@@ -15,21 +14,38 @@ type Label struct {
 	text   string
 	drawer artist.TextDrawer
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onFlexibleHeightChange func ()
 }
 
 // NewLabel creates a new label. If wrap is set to true, the text inside will be
 // wrapped.
 func NewLabel (text string, wrap bool) (element *Label) {
-	element = &Label {  }
+	element = &Label { }
+	element.theme.Case = theme.C("basic", "label")
 	element.Core, element.core = core.NewCore(element.handleResize)
-	face := theme.FontFaceRegular()
-	element.drawer.SetFace(face)
 	element.SetWrap(wrap)
 	element.SetText(text)
 	return
 }
 
+func (element *Label) redo () {
+	face := element.theme.FontFace (
+		theme.FontStyleRegular,
+		theme.FontSizeNormal)
+	element.drawer.SetFace(face)
+	element.updateMinimumSize()
+	bounds := element.Bounds()
+	if element.wrap {
+		element.drawer.SetMaxWidth(bounds.Dx())
+		element.drawer.SetMaxHeight(bounds.Dy())
+	}
+	element.draw()
+	element.core.DamageAll()
+}
+
 func (element *Label) handleResize () {
 	bounds := element.Bounds()
 	if element.wrap {
@@ -90,10 +106,37 @@ func (element *Label) SetWrap (wrap bool) {
 	}
 }
 
+// SetTheme sets the element's theme.
+func (element *Label) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.drawer.SetFace (element.theme.FontFace (
+		theme.FontStyleRegular,
+		theme.FontSizeNormal))
+	element.updateMinimumSize()
+	
+	if element.core.HasImage () {
+		element.draw()
+		element.core.DamageAll()
+	}
+}
+
+// SetConfig sets the element's configuration.
+func (element *Label) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.updateMinimumSize()
+	
+	if element.core.HasImage () {
+		element.draw()
+		element.core.DamageAll()
+	}
+}
+
 func (element *Label) updateMinimumSize () {
 	if element.wrap {
 		em := element.drawer.Em().Round()
-		if em < 1 { em = theme.Padding() }
+		if em < 1 { em = element.config.Padding() }
 		element.core.SetMinimumSize (
 			em, element.drawer.LineHeight().Round())
 		if element.onFlexibleHeightChange != nil {
@@ -108,15 +151,15 @@ func (element *Label) updateMinimumSize () {
 func (element *Label) draw () {
 	bounds := element.Bounds()
 
-	pattern, _ := theme.BackgroundPattern(theme.PatternState {
+	pattern := element.theme.Pattern (
-		Case: labelCase,
+		theme.PatternBackground,
-	})
+		theme.PatternState { })
 	artist.FillRectangle(element, pattern, bounds)
 
 	textBounds := element.drawer.LayoutBounds()
 
-	foreground, _ := theme.ForegroundPattern (theme.PatternState {
+	foreground :=  element.theme.Pattern (
-		Case: labelCase,
+		theme.PatternForeground,
-	})
+		theme.PatternState { })
-	element.drawer.Draw (element, foreground, bounds.Min.Sub(textBounds.Min))
+	element.drawer.Draw(element, foreground, bounds.Min.Sub(textBounds.Min))
 }

elements/basic/list.go

@@ -4,12 +4,11 @@ import "fmt"
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var listCase = theme.C("basic", "list")
-
 // List is an element that contains several objects that a user can select.
 type List struct {
 	*core.Core
@@ -27,6 +26,9 @@ type List struct {
 	scroll int
 	entries []ListEntry
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onScrollBoundsChange func ()
 	onNoEntrySelected func ()
 }
@@ -34,6 +36,7 @@ type List struct {
 // NewList creates a new list element with the specified entries.
 func NewList (entries ...ListEntry) (element *List) {
 	element = &List { selectedEntry: -1 }
+	element.theme.Case = theme.C("basic", "list")
 	element.Core, element.core = core.NewCore(element.handleResize)
 	element.FocusableCore,
 	element.focusableControl = core.NewFocusableCore (func () {
@@ -63,6 +66,44 @@ func (element *List) handleResize () {
 	}
 }
 
+// SetTheme sets the element's theme.
+func (element *List) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	for index, entry := range element.entries {
+		entry.SetTheme(element.theme.Theme)
+		element.entries[index] = entry
+	}
+	element.updateMinimumSize()
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *List) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	for index, entry := range element.entries {
+		entry.SetConfig(element.config)
+		element.entries[index] = entry
+	}
+	element.updateMinimumSize()
+	element.redo()
+}
+
+func (element *List) redo () {
+	for index, entry := range element.entries {
+		element.entries[index] = element.resizeEntryToFit(entry)
+	}
+
+	if element.core.HasImage() {
+		element.draw()
+		element.core.DamageAll()
+	}
+	if element.onScrollBoundsChange != nil {
+		element.onScrollBoundsChange()
+	}
+}
+
 // Collapse forces a minimum width and height upon the list. If a zero value is
 // given for a dimension, its minimum will be determined by the list's content.
 // If the list's height goes beyond the forced size, it will need to be accessed
@@ -164,9 +205,7 @@ func (element *List) ScrollAxes () (horizontal, vertical bool) {
 }
 
 func (element *List) scrollViewportHeight () (height int) {
-	_, inset := theme.ListPattern(theme.PatternState {
+	inset := element.theme.Inset(theme.PatternSunken)
-		Case: listCase,
-	})
 	return element.Bounds().Dy() - inset[0] - inset[2]
 }
 
@@ -198,6 +237,8 @@ func (element *List) CountEntries () (count int) {
 func (element *List) Append (entry ListEntry) {
 	// append
 	entry.Collapse(element.forcedMinimumWidth)
+	entry.SetTheme(element.theme.Theme)
+	entry.SetConfig(element.config)
 	element.entries = append(element.entries, entry)
 
 	// recalculate, redraw, notify
@@ -290,7 +331,7 @@ func (element *List) Replace (index int, entry ListEntry) {
 }
 
 func (element *List) selectUnderMouse (x, y int) (updated bool) {
-	_, inset := theme.ListPattern(theme.PatternState { })
+	inset := element.theme.Inset(theme.PatternSunken)
 	bounds := inset.Apply(element.Bounds())
 	mousePoint := image.Pt(x, y)
 	dot := image.Pt (
@@ -332,9 +373,7 @@ func (element *List) changeSelectionBy (delta int) (updated bool) {
 }
 
 func (element *List) resizeEntryToFit (entry ListEntry) (resized ListEntry) {
-	_, inset := theme.ListPattern(theme.PatternState {
+	inset := element.theme.Inset(theme.PatternSunken)
-		Case: listCase,
-	})
 	entry.Collapse(element.forcedMinimumWidth - inset[3] - inset[1])
 	return entry
 }
@@ -361,9 +400,7 @@ func (element *List) updateMinimumSize () {
 		minimumHeight = element.contentHeight
 	}
 
-	_, inset := theme.ListPattern(theme.PatternState {
+	inset := element.theme.Inset(theme.PatternSunken)
-		Case: listCase,
-	})
 	minimumHeight += inset[0] + inset[2]
 
 	element.core.SetMinimumSize(minimumWidth, minimumHeight)
@@ -372,8 +409,8 @@ func (element *List) updateMinimumSize () {
 func (element *List) draw () {
 	bounds := element.Bounds()
 
-	pattern, inset := theme.ListPattern(theme.PatternState {
+	inset := element.theme.Inset(theme.PatternSunken)
-		Case: listCase,
+	pattern := element.theme.Pattern (theme.PatternSunken, theme.PatternState {
 		Disabled: !element.Enabled(),
 		Focused: element.Focused(),
 	})

elements/basic/listentry.go

@@ -2,11 +2,10 @@ package basicElements
 
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 
-var listEntryCase = theme.C("basic", "listEntry")
-
 // ListEntry is an item that can be added to a list.
 type ListEntry struct {
 	drawer artist.TextDrawer
@@ -14,6 +13,10 @@ type ListEntry struct {
 	textPoint image.Point
 	text string
 	forcedMinimumWidth int
+	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onSelect func ()
 }
 
@@ -22,8 +25,8 @@ func NewListEntry (text string, onSelect func ()) (entry ListEntry) {
 		text:     text,
 		onSelect: onSelect,
 	}
+	entry.theme.Case = theme.C("basic", "listEntry")
 	entry.drawer.SetText([]rune(text))
-	entry.drawer.SetFace(theme.FontFaceRegular())
 	entry.updateBounds()
 	return
 }
@@ -34,6 +37,20 @@ func (entry *ListEntry) Collapse (width int) {
 	entry.updateBounds()
 }
 
+func (entry *ListEntry) SetTheme (new theme.Theme) {
+	if new == entry.theme.Theme { return }
+	entry.theme.Theme = new
+	entry.drawer.SetFace (entry.theme.FontFace (
+		theme.FontStyleRegular,
+		theme.FontSizeNormal))
+	entry.updateBounds()
+}
+
+func (entry *ListEntry) SetConfig (new config.Config) {
+	if new == entry.config.Config { return }
+	entry.config.Config = new
+}
+
 func (entry *ListEntry) updateBounds () {
 	entry.bounds = image.Rectangle { }
 	entry.bounds.Max.Y = entry.drawer.LineHeight().Round()
@@ -43,8 +60,7 @@ func (entry *ListEntry) updateBounds () {
 		entry.bounds.Max.X = entry.drawer.LayoutBounds().Dx()
 	}
 	
-	_, inset := theme.ItemPattern(theme.PatternState {
+	inset := entry.theme.Inset(theme.PatternRaised)
-	})
 	entry.bounds.Max.Y += inset[0] + inset[2]
 	
 	entry.textPoint =
@@ -60,20 +76,16 @@ func (entry *ListEntry) Draw (
 ) (
 	updatedRegion image.Rectangle,
 ) {
-	pattern, _ := theme.ItemPattern(theme.PatternState {
+	state := theme.PatternState {
-		Case: listEntryCase,
 		Focused: focused,
 		On: on,
-	})
+	}
+	pattern := entry.theme.Pattern (theme.PatternRaised, state)
 	artist.FillRectangle (
 		destination,
 		pattern,
 		entry.Bounds().Add(offset))
-	foreground, _ := theme.ForegroundPattern (theme.PatternState {
+	foreground := entry.theme.Pattern (theme.PatternForeground, state)
-		Case: listEntryCase,
-		Focused: focused,
-		On: on,
-	})
 	return entry.drawer.Draw (
 		destination,
 		foreground,

elements/basic/progressbar.go

@@ -2,6 +2,7 @@ package basicElements
 
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
@@ -10,14 +11,17 @@ type ProgressBar struct {
 	*core.Core
 	core core.CoreControl
 	progress float64
+	
+	config config.Wrapped
+	theme  theme.Wrapped
 }
 
 // NewProgressBar creates a new progress bar displaying the given progress
 // level.
 func NewProgressBar (progress float64) (element *ProgressBar) {
 	element = &ProgressBar { progress: progress }
+	element.theme.Case = theme.C("basic", "progressBar")
 	element.Core, element.core = core.NewCore(element.draw)
-	element.core.SetMinimumSize(theme.Padding() * 2, theme.Padding() * 2)
 	return
 }
 
@@ -31,16 +35,50 @@ func (element *ProgressBar) SetProgress (progress float64) {
 	}
 }
 
+// SetTheme sets the element's theme.
+func (element *ProgressBar) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.updateMinimumSize()
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *ProgressBar) SetConfig (new config.Config) {
+	if new == nil || new == element.config.Config { return }
+	element.config.Config = new
+	element.updateMinimumSize()
+	element.redo()
+}
+
+func (element (ProgressBar)) updateMinimumSize() {
+	element.core.SetMinimumSize (
+		element.config.Padding() * 2,
+		element.config.Padding() * 2)
+}
+
+func (element *ProgressBar) redo () {
+	if element.core.HasImage() {
+		element.draw()
+		element.core.DamageAll()
+	}
+}
+
 func (element *ProgressBar) draw () {
 	bounds := element.Bounds()
 
-	pattern, inset := theme.SunkenPattern(theme.PatternState { })
+	pattern := element.theme.Pattern (
+		theme.PatternSunken,
+		theme.PatternState { })
+	inset := element.theme.Inset(theme.PatternSunken)
 	artist.FillRectangle(element, pattern, bounds)
 	bounds = inset.Apply(bounds)
 	meterBounds := image.Rect (
 		bounds.Min.X, bounds.Min.Y,
 		bounds.Min.X + int(float64(bounds.Dx()) * element.progress),
 		bounds.Max.Y)
-	accent, _ := theme.AccentPattern(theme.PatternState { })
+	accent := element.theme.Pattern (
+		theme.PatternAccent,
+		theme.PatternState { })
 	artist.FillRectangle(element, accent, meterBounds)
 }

elements/basic/scrollcontainer.go

@@ -3,15 +3,12 @@ package basicElements
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var scrollContainerCase     = theme.C("basic", "scrollContainer")
-var scrollBarHorizontalCase = theme.C("basic", "scrollBarHorizontal")
-var scrollBarVerticalCase   = theme.C("basic", "scrollBarVertical")
-
 // ScrollContainer is a container that is capable of holding a scrollable
 // element.
 type ScrollContainer struct {
@@ -23,6 +20,7 @@ type ScrollContainer struct {
 	childWidth, childHeight int
 	
 	horizontal struct {
+		theme theme.Wrapped
 		exists bool
 		enabled bool
 		dragging bool
@@ -33,6 +31,7 @@ type ScrollContainer struct {
 	}
 
 	vertical struct {
+		theme theme.Wrapped
 		exists bool
 		enabled bool
 		dragging bool
@@ -42,6 +41,9 @@ type ScrollContainer struct {
 		bar image.Rectangle
 	}
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+
 	onFocusRequest func () (granted bool)
 	onFocusMotionRequest func (input.KeynavDirection) (granted bool)
 }
@@ -50,8 +52,11 @@ type ScrollContainer struct {
 // bars.
 func NewScrollContainer (horizontal, vertical bool) (element *ScrollContainer) {
 	element = &ScrollContainer { }
+	element.theme.Case = theme.C("basic", "scrollContainer")
+	element.horizontal.theme.Case = theme.C("basic", "scrollBarHorizontal")
+	element.vertical.theme.Case   = theme.C("basic", "scrollBarVertical")
+	
 	element.Core, element.core = core.NewCore(element.handleResize)
-	element.updateMinimumSize()
 	element.horizontal.exists = horizontal
 	element.vertical.exists   = vertical
 	return
@@ -75,6 +80,12 @@ func (element *ScrollContainer) Adopt (child elements.Scrollable) {
 	// adopt new child
 	element.child = child
 	if child != nil {
+		if child0, ok := child.(elements.Themeable); ok {
+			child0.SetTheme(element.theme.Theme)
+		}
+		if child0, ok := child.(elements.Configurable); ok {
+			child0.SetConfig(element.config.Config)
+		}
 		child.OnDamage(element.childDamageCallback)
 		child.OnMinimumSizeChange(element.updateMinimumSize)
 		child.OnScrollBoundsChange(element.childScrollBoundsChangeCallback)
@@ -85,8 +96,6 @@ func (element *ScrollContainer) Adopt (child elements.Scrollable) {
 				element.childFocusMotionRequestCallback)
 		}
 
-		// TODO: somehow inform the core that we do not in fact want to
-		// redraw the element.
 		element.updateMinimumSize()
 		
 		element.horizontal.enabled,
@@ -98,6 +107,34 @@ func (element *ScrollContainer) Adopt (child elements.Scrollable) {
 	}
 }
 
+// SetTheme sets the element's theme.
+func (element *ScrollContainer) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	if child, ok := element.child.(elements.Themeable); ok {
+		child.SetTheme(element.theme.Theme)
+	}
+	if element.core.HasImage() {
+		element.recalculate()
+		element.resizeChildToFit()
+		element.draw()
+	}
+}
+
+// SetConfig sets the element's configuration.
+func (element *ScrollContainer) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	if child, ok := element.child.(elements.Configurable); ok {
+		child.SetConfig(element.config.Config)
+	}
+	if element.core.HasImage() {
+		element.recalculate()
+		element.resizeChildToFit()
+		element.draw()
+	}
+}
+
 func (element *ScrollContainer) HandleKeyDown (key input.Key, modifiers input.Modifiers) {
 	if child, ok := element.child.(elements.KeyboardTarget); ok {
 		child.HandleKeyDown(key, modifiers)
@@ -111,6 +148,7 @@ func (element *ScrollContainer) HandleKeyUp (key input.Key, modifiers input.Modi
 }
 
 func (element *ScrollContainer) HandleMouseDown (x, y int, button input.Button) {
+	velocity := element.config.ScrollVelocity()
 	point := image.Pt(x, y)
 	if point.In(element.horizontal.bar) {
 		element.horizontal.dragging = true
@@ -123,9 +161,9 @@ func (element *ScrollContainer) HandleMouseDown (x, y int, button input.Button)
 		// FIXME: x backend and scroll container should pull these
 		// values from the same place
 		if x > element.horizontal.bar.Min.X {
-			element.scrollChildBy(16, 0)
+			element.scrollChildBy(velocity, 0)
 		} else {
-			element.scrollChildBy(-16, 0)
+			element.scrollChildBy(-velocity, 0)
 		}
 		
 	} else if point.In(element.vertical.bar) {
@@ -137,9 +175,9 @@ func (element *ScrollContainer) HandleMouseDown (x, y int, button input.Button)
 		
 	} else if point.In(element.vertical.gutter) {
 		if y > element.vertical.bar.Min.Y {
-			element.scrollChildBy(0, 16)
+			element.scrollChildBy(0, velocity)
 		} else {
-			element.scrollChildBy(0, -16)
+			element.scrollChildBy(0, -velocity)
 		}
 		
 	} else if child, ok := element.child.(elements.MouseTarget); ok {
@@ -281,22 +319,19 @@ func (element *ScrollContainer) resizeChildToFit () {
 }
 
 func (element *ScrollContainer) recalculate () {
-	_, gutterInsetHorizontal := theme.GutterPattern(theme.PatternState {
-		Case: scrollBarHorizontalCase,
-	})
-	_, gutterInsetVertical := theme.GutterPattern(theme.PatternState {
-		Case: scrollBarHorizontalCase,
-	})
-
 	horizontal := &element.horizontal
 	vertical   := &element.vertical
+	
+	gutterInsetHorizontal := horizontal.theme.Inset(theme.PatternGutter)
+	gutterInsetVertical   := vertical.theme.Inset(theme.PatternGutter)
+
 	bounds     := element.Bounds()
 	thicknessHorizontal :=
-		theme.HandleWidth() +
+		element.config.HandleWidth() +
 		gutterInsetHorizontal[3] +
 		gutterInsetHorizontal[1]
 	thicknessVertical :=
-		theme.HandleWidth() +
+		element.config.HandleWidth() +
 		gutterInsetVertical[3] +
 		gutterInsetVertical[1]
 
@@ -373,9 +408,8 @@ func (element *ScrollContainer) recalculate () {
 
 func (element *ScrollContainer) draw () {
 	artist.Paste(element, element.child, image.Point { })
-	deadPattern, _ := theme.DeadPattern(theme.PatternState {
+	deadPattern := element.theme.Pattern (
-		Case: scrollContainerCase,
+		theme.PatternDead, theme.PatternState { })
-	})
 	artist.FillRectangle (
 		element, deadPattern,
 		image.Rect (
@@ -388,32 +422,26 @@ func (element *ScrollContainer) draw () {
 }
 
 func (element *ScrollContainer) drawHorizontalBar () {
-	gutterPattern, _ := theme.GutterPattern (theme.PatternState {
+	state := theme.PatternState {
-		Case: scrollBarHorizontalCase,
-		Disabled: !element.horizontal.enabled,
-	})
-	artist.FillRectangle(element, gutterPattern, element.horizontal.gutter)
-	
-	handlePattern, _ := theme.HandlePattern (theme.PatternState {
-		Case: scrollBarHorizontalCase,
 		Disabled: !element.horizontal.enabled,
 		Pressed:  element.horizontal.dragging,
-	})
+	}
+	gutterPattern := element.horizontal.theme.Pattern(theme.PatternGutter, state)
+	artist.FillRectangle(element, gutterPattern, element.horizontal.gutter)
+	
+	handlePattern := element.horizontal.theme.Pattern(theme.PatternHandle, state)
 	artist.FillRectangle(element, handlePattern, element.horizontal.bar)
 }
 
 func (element *ScrollContainer) drawVerticalBar () {
-	gutterPattern, _ := theme.GutterPattern (theme.PatternState {
+	state := theme.PatternState {
-		Case: scrollBarVerticalCase,
-		Disabled: !element.vertical.enabled,
-	})
-	artist.FillRectangle(element, gutterPattern, element.vertical.gutter)
-	
-	handlePattern, _ := theme.HandlePattern (theme.PatternState {
-		Case: scrollBarVerticalCase,
 		Disabled: !element.vertical.enabled,
 		Pressed:  element.vertical.dragging,
-	})
+	}
+	gutterPattern := element.vertical.theme.Pattern(theme.PatternGutter, state)
+	artist.FillRectangle(element, gutterPattern, element.vertical.gutter)
+	
+	handlePattern := element.vertical.theme.Pattern(theme.PatternHandle, state)
 	artist.FillRectangle(element, handlePattern, element.vertical.bar)
 }
 
@@ -436,19 +464,15 @@ func (element *ScrollContainer) dragVerticalBar (mousePosition image.Point) {
 }
 
 func (element *ScrollContainer) updateMinimumSize () {
-	_, gutterInsetHorizontal := theme.GutterPattern(theme.PatternState {
+	gutterInsetHorizontal := element.horizontal.theme.Inset(theme.PatternGutter)
-		Case: scrollBarHorizontalCase,
+	gutterInsetVertical   := element.vertical.theme.Inset(theme.PatternGutter)
-	})
-	_, gutterInsetVertical := theme.GutterPattern(theme.PatternState {
-		Case: scrollBarHorizontalCase,
-	})
 
 	thicknessHorizontal :=
-		theme.HandleWidth() +
+		element.config.HandleWidth() +
 		gutterInsetHorizontal[3] +
 		gutterInsetHorizontal[1]
 	thicknessVertical :=
-		theme.HandleWidth() +
+		element.config.HandleWidth() +
 		gutterInsetVertical[3] +
 		gutterInsetVertical[1]
 	

elements/basic/spacer.go

@@ -1,16 +1,18 @@
 package basicElements
 
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var spacerCase = theme.C("basic", "spacer")
-
 // Spacer can be used to put space between two elements..
 type Spacer struct {
 	*core.Core
 	core core.CoreControl
 	line bool
+	
+	config config.Wrapped
+	theme  theme.Wrapped
 }
 
 // NewSpacer creates a new spacer. If line is set to true, the spacer will be
@@ -18,6 +20,7 @@ type Spacer struct {
 // will appear as a line.
 func NewSpacer (line bool) (element *Spacer) {
 	element = &Spacer { line: line }
+	element.theme.Case = theme.C("basic", "spacer")
 	element.Core, element.core = core.NewCore(element.draw)
 	element.core.SetMinimumSize(1, 1)
 	return
@@ -33,20 +36,39 @@ func (element *Spacer) SetLine (line bool) {
 	}
 }
 
+// SetTheme sets the element's theme.
+func (element *Spacer) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *Spacer) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.redo()
+}
+
+func (element *Spacer) redo () {
+	if !element.core.HasImage() {
+		element.draw()
+		element.core.DamageAll()
+	}
+}
+
 func (element *Spacer) draw () {
 	bounds := element.Bounds()
 
 	if element.line {
-		pattern, _ := theme.ForegroundPattern(theme.PatternState {
+		pattern := element.theme.Pattern (
-			Case: spacerCase,
+			theme.PatternForeground,
-			Disabled: true,
+			theme.PatternState { })
-		})
 		artist.FillRectangle(element, pattern, bounds)
 	} else {
-		pattern, _ := theme.BackgroundPattern(theme.PatternState {
+		pattern := element.theme.Pattern (
-			Case: spacerCase,
+			theme.PatternBackground,
-			Disabled: true,
+			theme.PatternState { })
-		})
 		artist.FillRectangle(element, pattern, bounds)
 	}
 }

elements/basic/switch.go

@@ -3,11 +3,10 @@ package basicElements
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var switchCase = theme.C("basic", "switch")
-
 // Switch is a toggle-able on/off switch with an optional label. It is
 // functionally identical to Checkbox, but plays a different semantic role.
 type Switch struct {
@@ -21,23 +20,24 @@ type Switch struct {
 	checked bool
 	text    string
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onToggle func ()
 }
 
 // NewSwitch creates a new switch with the specified label text.
 func NewSwitch (text string, on bool) (element *Switch) {
-	element = &Switch { checked: on, text: text }
+	element = &Switch {
+		checked: on,
+		text: text,
+	}
+	element.theme.Case = theme.C("basic", "switch")
 	element.Core, element.core = core.NewCore(element.draw)
 	element.FocusableCore,
-	element.focusableControl = core.NewFocusableCore (func () {
+	element.focusableControl = core.NewFocusableCore(element.redo)
-		if element.core.HasImage () {
-			element.draw()
-			element.core.DamageAll()
-		}
-	})
-	element.drawer.SetFace(theme.FontFaceRegular())
 	element.drawer.SetText([]rune(text))
-	element.calculateMinimumSize()
+	element.updateMinimumSize()
 	return
 }
 
@@ -45,10 +45,7 @@ func (element *Switch) HandleMouseDown (x, y int, button input.Button) {
 	if !element.Enabled() { return }
 	element.Focus()
 	element.pressed = true
-	if element.core.HasImage() {
+	element.redo()
-		element.draw()
-		element.core.DamageAll()
-	}
 }
 
 func (element *Switch) HandleMouseUp (x, y int, button input.Button) {
@@ -76,10 +73,7 @@ func (element *Switch) HandleMouseScroll (x, y int, deltaX, deltaY float64) { }
 func (element *Switch) HandleKeyDown (key input.Key, modifiers input.Modifiers) {
 	if key == input.KeyEnter {
 		element.pressed = true
-		if element.core.HasImage() {
+		element.redo()
-			element.draw()
-			element.core.DamageAll()
-		}
 	}
 }
 
@@ -87,10 +81,7 @@ func (element *Switch) HandleKeyUp (key input.Key, modifiers input.Modifiers) {
 	if key == input.KeyEnter && element.pressed {
 		element.pressed = false
 		element.checked = !element.checked
-		if element.core.HasImage() {
+		element.redo()
-			element.draw()
-			element.core.DamageAll()
-		}
 		if element.onToggle != nil {
 			element.onToggle()
 		}
@@ -118,15 +109,37 @@ func (element *Switch) SetText (text string) {
 
 	element.text = text
 	element.drawer.SetText([]rune(text))
-	element.calculateMinimumSize()
+	element.updateMinimumSize()
+	element.redo()
+}
 
+// SetTheme sets the element's theme.
+func (element *Switch) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.drawer.SetFace (element.theme.FontFace (
+		theme.FontStyleRegular,
+		theme.FontSizeNormal))
+	element.updateMinimumSize()
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *Switch) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.updateMinimumSize()
+	element.redo()
+}
+
+func (element *Switch) redo () {
 	if element.core.HasImage () {
 		element.draw()
 		element.core.DamageAll()
 	}
 }
 
-func (element *Switch) calculateMinimumSize () {
+func (element *Switch) updateMinimumSize () {
 	textBounds := element.drawer.LayoutBounds()
 	lineHeight := element.drawer.LineHeight().Round()
 	
@@ -134,7 +147,9 @@ func (element *Switch) calculateMinimumSize () {
 		element.core.SetMinimumSize(lineHeight * 2, lineHeight)
 	} else {
 		element.core.SetMinimumSize (
-			lineHeight * 2 + theme.Padding() + textBounds.Dx(),
+			lineHeight * 2 +
+			element.config.Padding() +
+			textBounds.Dx(),
 			lineHeight)
 	}
 }
@@ -143,9 +158,14 @@ func (element *Switch) draw () {
 	bounds := element.Bounds()
 	handleBounds := image.Rect(0, 0, bounds.Dy(), bounds.Dy()).Add(bounds.Min)
 	gutterBounds := image.Rect(0, 0, bounds.Dy() * 2, bounds.Dy()).Add(bounds.Min)
-	backgroundPattern, _ := theme.BackgroundPattern(theme.PatternState {
+
-		Case: switchCase,
+	state := theme.PatternState {
-	})
+		Disabled: !element.Enabled(),
+		Focused:  element.Focused(),
+		Pressed:  element.pressed,
+	}
+	backgroundPattern := element.theme.Pattern (
+		theme.PatternBackground, state)
 	artist.FillRectangle (element, backgroundPattern, bounds)
 
 	if element.checked {
@@ -162,33 +182,23 @@ func (element *Switch) draw () {
 		}
 	}
 
-	gutterPattern, _ := theme.GutterPattern(theme.PatternState {
+	gutterPattern := element.theme.Pattern (
-		Case: switchCase,
+		theme.PatternGutter, state)
-		Disabled: !element.Enabled(),
-		Focused:  element.Focused(),
-		Pressed:  element.pressed,
-	})
 	artist.FillRectangle(element, gutterPattern, gutterBounds)
 	
-	handlePattern, _ := theme.HandlePattern(theme.PatternState {
+	handlePattern := element.theme.Pattern (
-		Case: switchCase,
+		theme.PatternHandle, state)
-		Disabled: !element.Enabled(),
-		Focused:  element.Focused(),
-		Pressed:  element.pressed,
-	})
 	artist.FillRectangle(element, handlePattern, handleBounds)
 
 	textBounds := element.drawer.LayoutBounds()
 	offset := bounds.Min.Add(image.Point {
-		X: bounds.Dy() * 2 + theme.Padding(),
+		X: bounds.Dy() * 2 + element.config.Padding(),
 	})
 
 	offset.Y -= textBounds.Min.Y
 	offset.X -= textBounds.Min.X
 
-	foreground, _ := theme.ForegroundPattern (theme.PatternState {
+	foreground := element.theme.Pattern (
-		Case: switchCase,
+		theme.PatternForeground, state)
-		Disabled: !element.Enabled(),
-	})
 	element.drawer.Draw(element, foreground, offset)
 }

elements/basic/textbox.go

@@ -3,12 +3,11 @@ package basicElements
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/textmanip"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var textBoxCase = theme.C("basic", "textBox")
-
 // TextBox is a single-line text input.
 type TextBox struct {
 	*core.Core
@@ -24,6 +23,9 @@ type TextBox struct {
 	placeholderDrawer artist.TextDrawer
 	valueDrawer       artist.TextDrawer
 	
+	config config.Wrapped
+	theme  theme.Wrapped
+	
 	onKeyDown func (key input.Key, modifiers input.Modifiers) (handled bool)
 	onChange  func ()
 	onScrollBoundsChange func ()
@@ -34,6 +36,7 @@ type TextBox struct {
 // text.
 func NewTextBox (placeholder, value string) (element *TextBox) {
 	element = &TextBox { }
+	element.theme.Case = theme.C("basic", "textBox")
 	element.Core, element.core = core.NewCore(element.handleResize)
 	element.FocusableCore,
 	element.focusableControl = core.NewFocusableCore (func () {
@@ -42,8 +45,6 @@ func NewTextBox (placeholder, value string) (element *TextBox) {
 			element.core.DamageAll()
 		}
 	})
-	element.placeholderDrawer.SetFace(theme.FontFaceRegular())
-	element.valueDrawer.SetFace(theme.FontFaceRegular())
 	element.placeholder = placeholder
 	element.placeholderDrawer.SetText([]rune(placeholder))
 	element.updateMinimumSize()
@@ -130,9 +131,8 @@ func (element *TextBox) HandleKeyDown(key input.Key, modifiers input.Modifiers)
 		element.onScrollBoundsChange()
 	}
 	
-	if altered && element.core.HasImage () {
+	if altered {
-		element.draw()
+		element.redo()
-		element.core.DamageAll()
 	}
 }
 
@@ -145,10 +145,7 @@ func (element *TextBox) SetPlaceholder (placeholder string) {
 	element.placeholderDrawer.SetText([]rune(placeholder))
 	
 	element.updateMinimumSize()
-	if element.core.HasImage () {
+	element.redo()
-		element.draw()
-		element.core.DamageAll()
-	}
 }
 
 func (element *TextBox) SetValue (text string) {
@@ -161,11 +158,7 @@ func (element *TextBox) SetValue (text string) {
 		element.cursor = element.valueDrawer.Length()
 	}
 	element.scrollToCursor()
-	
+	element.redo()
-	if element.core.HasImage () {
-		element.draw()
-		element.core.DamageAll()
-	}
 }
 
 func (element *TextBox) Value () (value string) {
@@ -203,7 +196,7 @@ func (element *TextBox) ScrollViewportBounds () (bounds image.Rectangle) {
 }
 
 func (element *TextBox) scrollViewportWidth () (width int) {
-	return element.Bounds().Inset(theme.Padding()).Dx()
+	return element.Bounds().Inset(element.config.Padding()).Dx()
 }
 
 // ScrollTo scrolls the viewport to the specified point relative to
@@ -218,10 +211,7 @@ func (element *TextBox) ScrollTo (position image.Point) {
 	maxPosition   := contentBounds.Max.X - element.scrollViewportWidth()
 	if element.scroll > maxPosition { element.scroll = maxPosition }
 
-	if element.core.HasImage () {
+	element.redo()
-		element.draw()
-		element.core.DamageAll()
-	}
 	if element.onScrollBoundsChange != nil {
 		element.onScrollBoundsChange()
 	}
@@ -236,18 +226,6 @@ func (element *TextBox) OnScrollBoundsChange (callback func ()) {
 	element.onScrollBoundsChange = callback
 }
 
-func (element *TextBox) updateMinimumSize () {
-	textBounds := element.placeholderDrawer.LayoutBounds()
-	_, inset := theme.InputPattern(theme.PatternState {
-		Case: textBoxCase,
-	})
-	element.core.SetMinimumSize (
-		textBounds.Dx() +
-		theme.Padding() * 2 + inset[3] + inset[1],
-		element.placeholderDrawer.LineHeight().Round() +
-		theme.Padding() * 2 + inset[0] + inset[2])
-}
-
 func (element *TextBox) runOnChange () {
 	if element.onChange != nil {
 		element.onChange()
@@ -257,7 +235,7 @@ func (element *TextBox) runOnChange () {
 func (element *TextBox) scrollToCursor () {
 	if !element.core.HasImage() { return }
 
-	bounds := element.Bounds().Inset(theme.Padding())
+	bounds := element.Bounds().Inset(element.config.Padding())
 	bounds = bounds.Sub(bounds.Min)
 	bounds.Max.X -= element.valueDrawer.Em().Round()
 	cursorPosition := element.valueDrawer.PositionOf(element.cursor)
@@ -272,28 +250,64 @@ func (element *TextBox) scrollToCursor () {
 	}
 }
 
+// SetTheme sets the element's theme.
+func (element *TextBox) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	face := element.theme.FontFace (
+		theme.FontStyleRegular,
+		theme.FontSizeNormal)
+	element.placeholderDrawer.SetFace(face)
+	element.valueDrawer.SetFace(face)
+	element.updateMinimumSize()
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *TextBox) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.updateMinimumSize()
+	element.redo()
+}
+
+func (element *TextBox) updateMinimumSize () {
+	textBounds := element.placeholderDrawer.LayoutBounds()
+	element.core.SetMinimumSize (
+		textBounds.Dx() +
+		element.config.Padding() * 2,
+		element.placeholderDrawer.LineHeight().Round() +
+		element.config.Padding() * 2)
+}
+
+func (element *TextBox) redo () {
+	if element.core.HasImage () {
+		element.draw()
+		element.core.DamageAll()
+	}
+}
+
 func (element *TextBox) draw () {
 	bounds := element.Bounds()
 
 	// FIXME: take index into account
-	pattern, inset := theme.InputPattern(theme.PatternState {
+	state := theme.PatternState {
-		Case:     textBoxCase,
 		Disabled: !element.Enabled(),
 		Focused:  element.Focused(),
-	})
+	}
+	pattern := element.theme.Pattern(theme.PatternSunken, state)
 	artist.FillRectangle(element, pattern, bounds)
 
 	if len(element.text) == 0 && !element.Focused() {
 		// draw placeholder
 		textBounds := element.placeholderDrawer.LayoutBounds()
 		offset := bounds.Min.Add (image.Point {
-			X: theme.Padding() + inset[3],
+			X: element.config.Padding(),
-			Y: theme.Padding() + inset[0],
+			Y: element.config.Padding(),
-		})
-		foreground, _ := theme.ForegroundPattern(theme.PatternState {
-			Case: textBoxCase,
-			Disabled: true,
 		})
+		foreground := element.theme.Pattern (
+			theme.PatternForeground,
+			theme.PatternState { Disabled: true })
 		element.placeholderDrawer.Draw (
 			element,
 			foreground,
@@ -302,13 +316,11 @@ func (element *TextBox) draw () {
 		// draw input value
 		textBounds := element.valueDrawer.LayoutBounds()
 		offset := bounds.Min.Add (image.Point {
-			X: theme.Padding() + inset[3] - element.scroll,
+			X: element.config.Padding() - element.scroll,
-			Y: theme.Padding() + inset[0],
+			Y: element.config.Padding(),
-		})
-		foreground, _ := theme.ForegroundPattern(theme.PatternState {
-			Case: textBoxCase,
-			Disabled: !element.Enabled(),
 		})
+		foreground := element.theme.Pattern (
+			theme.PatternForeground,  state)
 		element.valueDrawer.Draw (
 			element,
 			foreground,
@@ -318,9 +330,6 @@ func (element *TextBox) draw () {
 			// cursor
 			cursorPosition := element.valueDrawer.PositionOf (
 				element.cursor)
-			foreground, _ := theme.ForegroundPattern(theme.PatternState {
-				Case: textBoxCase,
-			})
 			artist.Line (
 				element,
 				foreground, 1,

elements/core/core.go

@@ -14,14 +14,21 @@ type Core struct {
 		minimumHeight int
 	}
 
-	drawSizeChange func ()
+	drawSizeChange      func ()
 	onMinimumSizeChange func ()
 	onDamage func (region canvas.Canvas)
 }
 
 // NewCore creates a new element core and its corresponding control.
-func NewCore (drawSizeChange func ()) (core *Core, control CoreControl) {
+func NewCore (
-	core    = &Core { drawSizeChange: drawSizeChange }
+	drawSizeChange func (),
+) (
+	core *Core,
+	control CoreControl,
+) {
+	core = &Core {
+		drawSizeChange: drawSizeChange,
+	}
 	control = CoreControl { core: core }
 	return
 }

elements/element.go

@@ -2,7 +2,9 @@ package elements
 
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/input"
+import "git.tebibyte.media/sashakoshka/tomo/theme"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 
 // Element represents a basic on-screen object.
 type Element interface {
@@ -37,7 +39,8 @@ type Element interface {
 type Focusable interface {
 	Element
 
-	// Focused returns whether or not this element is currently focused.
+	// Focused returns whether or not this element or any of its children
+	// are currently focused.
 	Focused () (selected bool)
 
 	// Focus focuses this element, if its parent element grants the
@@ -157,3 +160,23 @@ type Scrollable interface {
 	// ScrollContentBounds, ScrollViewportBounds, or ScrollAxes are changed.
 	OnScrollBoundsChange (callback func ())
 }
+
+// Themeable represents an element that can modify its appearance to fit within
+// a theme.
+type Themeable interface {
+	Element
+	
+	// SetTheme sets the element's theme to something fulfilling the
+	// theme.Theme interface.
+	SetTheme (theme.Theme)
+}
+
+// Configurable represents an element that can modify its behavior to fit within
+// a set of configuration parameters.
+type Configurable interface {
+	Element
+	
+	// SetConfig sets the element's configuration to something fulfilling
+	// the config.Config interface.
+	SetConfig (config.Config)
+}

elements/fun/clock.go

@@ -4,21 +4,24 @@ import "time"
 import "math"
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
 
-var clockCase = theme.C("fun", "clock")
-
 // AnalogClock can display the time of day in an analog format.
 type AnalogClock struct {
 	*core.Core
 	core core.CoreControl
 	time time.Time
+	
+	config config.Wrapped
+	theme  theme.Wrapped
 }
 
 // NewAnalogClock creates a new analog clock that displays the specified time.
 func NewAnalogClock (newTime time.Time) (element *AnalogClock) {
 	element = &AnalogClock { }
+	element.theme.Case = theme.C("fun", "clock")
 	element.Core, element.core = core.NewCore(element.draw)
 	element.core.SetMinimumSize(64, 64)
 	return
@@ -28,6 +31,24 @@ func NewAnalogClock (newTime time.Time) (element *AnalogClock) {
 func (element *AnalogClock) SetTime (newTime time.Time) {
 	if newTime == element.time { return }
 	element.time = newTime
+	element.redo()
+}
+
+// SetTheme sets the element's theme.
+func (element *AnalogClock) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *AnalogClock) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.redo()
+}
+
+func (element *AnalogClock) redo () {
 	if element.core.HasImage() {
 		element.draw()
 		element.core.DamageAll()
@@ -37,19 +58,15 @@ func (element *AnalogClock) SetTime (newTime time.Time) {
 func (element *AnalogClock) draw () {
 	bounds := element.Bounds()
 
-	pattern, inset := theme.SunkenPattern(theme.PatternState {
+	state := theme.PatternState { }
-		Case: clockCase,
+	pattern := element.theme.Pattern(theme.PatternSunken, state)
-	})
+	inset   := element.theme.Inset(theme.PatternSunken)
 	artist.FillRectangle(element, pattern, bounds)
 
 	bounds = inset.Apply(bounds)
 
-	foreground, _ := theme.ForegroundPattern(theme.PatternState {
+	foreground := element.theme.Pattern(theme.PatternForeground, state)
-		Case: clockCase,
+	accent     := element.theme.Pattern(theme.PatternAccent, state)
-	})
-	accent, _ := theme.AccentPattern(theme.PatternState {
-		Case: clockCase,
-	})
 
 	for hour := 0; hour < 12; hour ++ {
 		element.radialLine (
@@ -71,7 +88,7 @@ func (element *AnalogClock) FlexibleHeightFor (width int) (height int) {
 	return width
 }
 
-// OnFlexibleHeightChange sets a function to be calle dwhen the parameters
+// OnFlexibleHeightChange sets a function to be called when the parameters
 // affecting the clock's flexible height change.
 func (element *AnalogClock) OnFlexibleHeightChange (func ()) { }
 

elements/fun/piano.go

@@ -0,0 +1,244 @@
+package fun
+
+import "image"
+import "git.tebibyte.media/sashakoshka/tomo/input"
+import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
+import "git.tebibyte.media/sashakoshka/tomo/artist"
+import "git.tebibyte.media/sashakoshka/tomo/elements/core"
+
+// Octave represents a MIDI octave.
+type Octave int
+
+// Note returns the note at the specified scale degree in the chromatic scale.
+func (octave Octave) Note (degree int) Note {
+	return Note(int(octave + 1) * 12 + degree)
+}
+
+// Note represents a MIDI note.
+type Note int
+
+// Octave returns the octave of the note
+func (note Note) Octave () int {
+	return int(note / 12 - 1)
+}
+
+// Degree returns the scale degree of the note in the chromatic scale.
+func (note Note) Degree () int {
+	mod := note % 12
+	if mod < 0 { mod += 12 }
+	return int(mod)
+}
+
+// IsSharp returns whether or not the note is a sharp.
+func (note Note) IsSharp () bool {
+	degree := note.Degree()
+	return degree == 1 ||
+		degree == 3 ||
+		degree == 6 ||
+		degree == 8 ||
+		degree == 10
+}
+
+const pianoKeyWidth = 18
+
+type pianoKey struct {
+	image.Rectangle
+	Note
+}
+
+type Piano struct {
+	*core.Core
+	core core.CoreControl
+	low, high Octave
+	
+	config config.Wrapped
+	theme  theme.Wrapped
+
+	flatKeys  []pianoKey
+	sharpKeys []pianoKey
+
+	pressed *pianoKey
+
+	onPress   func (Note)
+	onRelease func (Note)
+}
+
+func NewPiano (low, high Octave) (element *Piano) {
+	element = &Piano {
+		low:  low,
+		high: high,
+	}
+	element.theme.Case = theme.C("fun", "piano")
+	element.Core, element.core = core.NewCore (func () {
+		element.recalculate()
+		element.draw()
+	})
+	element.updateMinimumSize()
+	return
+}
+
+// OnPress sets a function to be called when a key is pressed.
+func (element *Piano) OnPress (callback func (note Note)) {
+	element.onPress = callback
+}
+
+// OnRelease sets a function to be called when a key is released.
+func (element *Piano) OnRelease (callback func (note Note)) {
+	element.onRelease = callback
+}
+
+func (element *Piano) HandleMouseDown (x, y int, button input.Button) {
+	if button != input.ButtonLeft { return }
+	element.pressUnderMouseCursor(image.Pt(x, y))
+}
+
+func (element *Piano) HandleMouseUp (x, y int, button input.Button) {
+	if button != input.ButtonLeft { return }
+	if element.onRelease != nil {
+		element.onRelease((*element.pressed).Note)
+	}
+	element.pressed = nil
+	element.redo()
+}
+
+func (element *Piano) HandleMouseMove (x, y int) {
+	if element.pressed == nil { return }
+	element.pressUnderMouseCursor(image.Pt(x, y))
+}
+
+func (element *Piano) HandleMouseScroll (x, y int, deltaX, deltaY float64) { }
+
+func (element *Piano) pressUnderMouseCursor (point image.Point) {
+	// release previous note
+	if element.pressed != nil && element.onRelease != nil {
+		element.onRelease((*element.pressed).Note)
+	}
+
+	// find out which note is being pressed
+	newKey := (*pianoKey)(nil)
+	for index, key := range element.flatKeys {
+		if point.In(key.Rectangle) {
+			newKey = &element.flatKeys[index]
+			break
+		}
+	}
+	for index, key := range element.sharpKeys {
+		if point.In(key.Rectangle) {
+			newKey = &element.sharpKeys[index]
+			break
+		}
+	}
+	if newKey == nil { return }
+	
+	if newKey != element.pressed {
+		// press new note
+		element.pressed = newKey
+		if element.onPress != nil {
+			element.onPress((*element.pressed).Note)
+		}
+		element.redo()
+	}
+}
+
+// SetTheme sets the element's theme.
+func (element *Piano) SetTheme (new theme.Theme) {
+	if new == element.theme.Theme { return }
+	element.theme.Theme = new
+	element.updateMinimumSize()
+	element.recalculate()
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *Piano) SetConfig (new config.Config) {
+	if new == element.config.Config { return }
+	element.config.Config = new
+	element.updateMinimumSize()
+	element.recalculate()
+	element.redo()
+}
+
+func (element *Piano) updateMinimumSize () {
+	element.core.SetMinimumSize (
+		pianoKeyWidth * 7 * element.countOctaves(), 64)
+}
+
+func (element *Piano) countOctaves () int {
+	return int(element.high - element.low + 1)
+}
+
+func (element *Piano) countFlats () int {
+	return element.countOctaves() * 8
+}
+
+func (element *Piano) countSharps () int {
+	return element.countOctaves() * 5
+}
+
+func (element *Piano) redo () {
+	if element.core.HasImage() {
+		element.draw()
+		element.core.DamageAll()
+	}
+}
+
+func (element *Piano) recalculate () {
+	element.flatKeys  = make([]pianoKey, element.countFlats())
+	element.sharpKeys = make([]pianoKey, element.countSharps())
+
+	bounds := element.Bounds()
+	dot := bounds.Min
+	note := element.low.Note(0)
+	limit := element.high.Note(12)
+	flatIndex := 0
+	sharpIndex := 0
+	for note < limit {
+		if note.IsSharp() {
+			element.sharpKeys[sharpIndex].Rectangle = image.Rect (
+				-(pianoKeyWidth * 3) / 7, 0,
+				(pianoKeyWidth * 3) / 7,
+				bounds.Dy() / 2).Add(dot)
+			element.sharpKeys[sharpIndex].Note = note
+			sharpIndex ++
+		} else {
+			element.flatKeys[flatIndex].Rectangle = image.Rect (
+				0, 0, pianoKeyWidth, bounds.Dy()).Add(dot)
+			dot.X += pianoKeyWidth
+			element.flatKeys[flatIndex].Note = note
+			flatIndex ++
+		}
+		note ++
+	}
+}
+
+func (element *Piano) draw () {
+	for _, key := range element.flatKeys {
+		element.drawFlat (
+			key.Rectangle,
+			element.pressed != nil &&
+			(*element.pressed).Note == key.Note)
+	}
+	for _, key := range element.sharpKeys {
+		element.drawSharp (
+			key.Rectangle,
+			element.pressed != nil &&
+			(*element.pressed).Note == key.Note)
+	}
+}
+
+func (element *Piano) drawFlat (bounds image.Rectangle, pressed bool) {
+	state := theme.PatternState {
+		Pressed: pressed,
+	}
+	pattern := element.theme.Pattern(theme.PatternButton, state)
+	artist.FillRectangle(element, pattern, bounds)
+}
+
+func (element *Piano) drawSharp (bounds image.Rectangle, pressed bool) {
+	state := theme.PatternState {
+		Pressed: pressed,
+	}
+	pattern := element.theme.Pattern(theme.PatternButton, state)
+	artist.FillRectangle(element, pattern, bounds)
+}

elements/testing/artist.go

@@ -26,6 +26,8 @@ func NewArtist () (element *Artist) {
 
 func (element *Artist) draw () {
 	bounds := element.Bounds()
+	artist.FillRectangle(element, artist.NewUniform(hex(0)), bounds)
+	
 	element.cellBounds.Max.X = bounds.Min.X + bounds.Dx() / 5
 	element.cellBounds.Max.Y = bounds.Min.Y + (bounds.Dy() - 48) / 8
 

elements/testing/mouse.go

@@ -3,6 +3,7 @@ package testing
 import "image"
 import "image/color"
 import "git.tebibyte.media/sashakoshka/tomo/input"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/theme"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/elements/core"
@@ -15,20 +16,45 @@ type Mouse struct {
 	drawing      bool
 	color        artist.Pattern
 	lastMousePos image.Point
+	
+	config config.Config
+	theme  theme.Theme
+	c      theme.Case
 }
 
 // NewMouse creates a new mouse test element.
 func NewMouse () (element *Mouse) {
-	element = &Mouse { }
+	element = &Mouse { c: theme.C("testing", "mouse") }
 	element.Core, element.core = core.NewCore(element.draw)
 	element.core.SetMinimumSize(32, 32)
 	element.color = artist.NewUniform(color.Black)
 	return
 }
 
+// SetTheme sets the element's theme.
+func (element *Mouse) SetTheme (new theme.Theme) {
+	element.theme = new
+	element.redo()
+}
+
+// SetConfig sets the element's configuration.
+func (element *Mouse) SetConfig (new config.Config) {
+	element.config = new
+	element.redo()
+}
+
+func (element *Mouse) redo () {
+	if !element.core.HasImage() { return }
+	element.draw()
+	element.core.DamageAll()
+}
+
 func (element *Mouse) draw () {
 	bounds := element.Bounds()
-	pattern, _ := theme.AccentPattern(theme.PatternState { })
+	pattern := element.theme.Pattern (
+		theme.PatternAccent,
+		element.c,
+		theme.PatternState { })
 	artist.FillRectangle(element, pattern, bounds)
 	artist.StrokeRectangle (
 		element,

examples/goroutines/main.go

@@ -15,7 +15,7 @@ func main () {
 
 func run () {
 	window, _ := tomo.NewWindow(2, 2)
-	window.SetTitle("clock")
+	window.SetTitle("Clock")
 	container := basicElements.NewContainer(basicLayouts.Vertical { true, true })
 	window.Adopt(container)
 

examples/piano/main.go

@@ -0,0 +1,26 @@
+package main
+
+import "git.tebibyte.media/sashakoshka/tomo"
+import "git.tebibyte.media/sashakoshka/tomo/layouts/basic"
+import "git.tebibyte.media/sashakoshka/tomo/elements/fun"
+import "git.tebibyte.media/sashakoshka/tomo/elements/basic"
+import _ "git.tebibyte.media/sashakoshka/tomo/backends/x"
+
+func main () {
+	tomo.Run(run)
+}
+
+func run () {
+	window, _ := tomo.NewWindow(2, 2)
+	window.SetTitle("Piano")
+	container := basicElements.NewContainer(basicLayouts.Vertical { true, true })
+	window.Adopt(container)
+
+	label := basicElements.NewLabel("Play a song!", false)
+	container.Adopt(label, false)
+	piano := fun.NewPiano(3, 5)
+	container.Adopt(piano, true)
+	
+	window.OnClose(tomo.Stop)
+	window.Show()
+}

theme/button.go

@@ -1,48 +0,0 @@
-package theme
-
-import "git.tebibyte.media/sashakoshka/tomo/artist"
-
-var buttonPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xCCD5D2FF)),
-			artist.NewUniform(hex(0x4B5B59FF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
-var selectedButtonPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xCCD5D2FF)),
-			artist.NewUniform(hex(0x4B5B59FF)),
-		},
-	},
-	artist.Stroke { Weight: 1, Pattern: accentPattern },
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
-var pressedButtonPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0x4B5B59FF)),
-			artist.NewUniform(hex(0x8D9894FF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
-var pressedSelectedButtonPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0x4B5B59FF)),
-			artist.NewUniform(hex(0x8D9894FF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
-var disabledButtonPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
-	artist.Stroke { Pattern: backgroundPattern })

theme/default.go

@@ -0,0 +1,179 @@
+package theme
+
+import "image"
+import "golang.org/x/image/font"
+import "git.tebibyte.media/sashakoshka/tomo/artist"
+import "git.tebibyte.media/sashakoshka/tomo/defaultfont"
+
+// Default is the default theme.
+type Default struct { }
+
+// FontFace returns the default font face.
+func (Default) FontFace (style FontStyle, size FontSize, c Case) font.Face {
+	switch style {
+	case FontStyleBold:
+		return defaultfont.FaceBold
+	case FontStyleItalic:
+		return defaultfont.FaceItalic
+	case FontStyleBoldItalic:
+		return defaultfont.FaceBoldItalic
+	default:
+		return defaultfont.FaceRegular
+	}
+}
+
+// Icon returns an icon from the default set corresponding to the given name.
+func (Default) Icon (string, Case) artist.Pattern {
+	// TODO
+	return uhex(0)
+}
+
+// Pattern returns a pattern from the default theme corresponding to the given
+// pattern ID.
+func (Default) Pattern (
+	pattern Pattern,
+	c Case,
+	state PatternState,
+) artist.Pattern {
+	switch pattern {
+	case PatternAccent:
+		return accentPattern
+	case PatternBackground:
+		return backgroundPattern
+	case PatternForeground:
+		if state.Disabled || c == C("basic", "spacer") {
+			return weakForegroundPattern
+		} else {
+			return foregroundPattern
+		}
+	case PatternDead:
+		return deadPattern
+	case PatternRaised:
+		if c == C("basic", "listEntry") {
+			if state.Focused {
+				if state.On {
+					return focusedOnListEntryPattern
+				} else {
+					return focusedListEntryPattern
+				}
+			} else {
+				if state.On {
+					return onListEntryPattern
+				} else {
+					return listEntryPattern
+				}
+			}
+		} else {
+			if state.Focused {
+				return selectedRaisedPattern
+			} else {
+				return raisedPattern
+			}
+		}
+	case PatternSunken:
+		if c == C("basic", "list") {
+			if state.Focused {
+				return focusedListPattern
+			} else {
+				return listPattern
+			}
+		} else if c == C("basic", "textBox") {
+			if state.Disabled {
+				return disabledInputPattern
+			} else {
+				if state.Focused {
+					return selectedInputPattern
+				} else {
+					return inputPattern
+				}
+			}
+		} else {
+			return sunkenPattern
+		}
+	case PatternPinboard:
+		return texturedSunkenPattern
+	case PatternButton:
+		if state.Disabled {
+			return disabledButtonPattern
+		} else {
+			if state.Pressed || state.On && c == C("basic", "checkbox") {
+				if state.Focused {
+					return pressedSelectedButtonPattern
+				} else {
+					return pressedButtonPattern
+				}
+			} else {
+				if state.Focused {
+					return selectedButtonPattern
+				} else {
+					return buttonPattern
+				}
+			}
+		}
+	case PatternInput:
+		if state.Disabled {
+			return disabledInputPattern
+		} else {
+			if state.Focused {
+				return selectedInputPattern
+			} else {
+				return inputPattern
+			}
+		}
+	case PatternGutter:
+		if state.Disabled {
+			return disabledScrollGutterPattern
+		} else {
+			return scrollGutterPattern
+		}
+	case PatternHandle:
+		if state.Disabled {
+			return disabledScrollBarPattern
+		} else {
+			if state.Focused {
+				if state.Pressed {
+					return pressedSelectedScrollBarPattern
+				} else {
+					return selectedScrollBarPattern
+				}
+			} else {
+				if state.Pressed {
+					return pressedScrollBarPattern
+				} else {
+					return scrollBarPattern
+				}
+			}
+		}
+	default:
+		return uhex(0)
+	}
+}
+
+// Inset returns the default inset value for the given pattern.
+func (Default) Inset (pattern Pattern, c Case) Inset {
+	switch pattern {
+	case PatternRaised:
+		if c == C("basic", "listEntry") {
+			return Inset { 4, 6, 4, 6 }
+		} else {
+			return Inset { 1, 1, 1, 1 }
+		}
+	case PatternSunken:
+		if c == C("basic", "list") {
+			return Inset { 2, 1, 2, 1 }
+		} else if c == C("basic", "progressBar") {
+			return Inset { 2, 1, 1, 2 }
+		} else {
+			return Inset { 1, 1, 1, 1 }
+		}
+	
+	case PatternInput, PatternButton, PatternHandle, PatternPinboard:
+		return Inset { 1, 1, 1, 1}
+	default: return Inset { }
+	}
+}
+
+// Sink returns the default sink vector for the given pattern.
+func (Default) Sink (pattern Pattern, c Case) image.Point {
+	return image.Point { 1, 1 }
+}

theme/defaultpatterns.go

@@ -0,0 +1,237 @@
+package theme
+
+import "image/color"
+import "git.tebibyte.media/sashakoshka/tomo/artist"
+
+var accentPattern         = artist.NewUniform(hex(0x408090FF))
+var backgroundPattern     = artist.NewUniform(color.Gray16 { 0xAAAA })
+var foregroundPattern     = artist.NewUniform(color.Gray16 { 0x0000 })
+var weakForegroundPattern = artist.NewUniform(color.Gray16 { 0x4444 })
+var strokePattern         = artist.NewUniform(color.Gray16 { 0x0000 })
+
+var sunkenPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0x3b534eFF)),
+			artist.NewUniform(hex(0x97a09cFF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x97a09cFF)) })
+
+var texturedSunkenPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0x3b534eFF)),
+			artist.NewUniform(hex(0x97a09cFF)),
+		},
+	},
+	// artist.Stroke { Pattern: artist.Striped {
+		// First: artist.Stroke {
+			// Weight: 2,
+			// Pattern: artist.NewUniform(hex(0x97a09cFF)),
+		// },
+		// Second: artist.Stroke {
+			// Weight: 1,
+			// Pattern: artist.NewUniform(hex(0x6e8079FF)),
+		// },
+	// }})
+	
+	artist.Stroke { Pattern: artist.Noisy {
+		Low:  artist.NewUniform(hex(0x97a09cFF)),
+		High: artist.NewUniform(hex(0x6e8079FF)),
+	}})
+
+var raisedPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xDBDBDBFF)),
+			artist.NewUniform(hex(0x383C3AFF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0xAAAAAAFF)) })
+
+var selectedRaisedPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xDBDBDBFF)),
+			artist.NewUniform(hex(0x383C3AFF)),
+		},
+	},
+	artist.Stroke { Weight: 1, Pattern: accentPattern },
+	artist.Stroke { Pattern: artist.NewUniform(hex(0xAAAAAAFF)) })
+
+var deadPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x97a09cFF)) })
+
+var buttonPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xCCD5D2FF)),
+			artist.NewUniform(hex(0x4B5B59FF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
+var selectedButtonPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xCCD5D2FF)),
+			artist.NewUniform(hex(0x4B5B59FF)),
+		},
+	},
+	artist.Stroke { Weight: 1, Pattern: accentPattern },
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
+
+var pressedButtonPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0x4B5B59FF)),
+			artist.NewUniform(hex(0x8D9894FF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
+var pressedSelectedButtonPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0x4B5B59FF)),
+			artist.NewUniform(hex(0x8D9894FF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
+var disabledButtonPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
+	artist.Stroke { Pattern: backgroundPattern })
+
+var inputPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0x89925AFF)),
+			artist.NewUniform(hex(0xD2CB9AFF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0xD2CB9AFF)) })
+var selectedInputPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke { Weight: 1, Pattern: accentPattern },
+	artist.Stroke { Pattern: artist.NewUniform(hex(0xD2CB9AFF)) })
+var disabledInputPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
+	artist.Stroke { Pattern: backgroundPattern })
+
+var listPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			uhex(0x383C3AFF),
+			uhex(0x999C99FF),
+		},
+	},
+	artist.Stroke { Pattern: uhex(0x999C99FF) })
+
+var focusedListPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke { Weight: 1, Pattern: accentPattern },
+	artist.Stroke { Pattern: uhex(0x999C99FF) })
+
+var listEntryPattern = artist.Padded {
+	Stroke: uhex(0x383C3AFF),
+	Fill:   uhex(0x999C99FF),
+	Sides:  []int { 0, 0, 0, 1 },
+}
+
+var onListEntryPattern = artist.Padded {
+	Stroke: uhex(0x383C3AFF),
+	Fill:   uhex(0x6e8079FF),
+	Sides:  []int { 0, 0, 0, 1 },
+}
+
+var focusedListEntryPattern = artist.Padded {
+	Stroke: accentPattern,
+	Fill:   uhex(0x999C99FF),
+	Sides:  []int { 0, 1, 0, 1 },
+}
+
+var focusedOnListEntryPattern = artist.Padded {
+	Stroke: accentPattern,
+	Fill:   uhex(0x6e8079FF),
+	Sides:  []int { 0, 1, 0, 1 },
+}
+
+var scrollGutterPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0x3b534eFF)),
+			artist.NewUniform(hex(0x6e8079FF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x6e8079FF)) })
+var disabledScrollGutterPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
+	artist.Stroke { Pattern: backgroundPattern })
+var scrollBarPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xCCD5D2FF)),
+			artist.NewUniform(hex(0x4B5B59FF)),
+		},
+	},
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
+var selectedScrollBarPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xCCD5D2FF)),
+			artist.NewUniform(hex(0x4B5B59FF)),
+		},
+	},
+	artist.Stroke { Weight: 1, Pattern: accentPattern },
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
+var pressedScrollBarPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xCCD5D2FF)),
+			artist.NewUniform(hex(0x4B5B59FF)),
+		},
+	},
+	artist.Stroke { Weight: 1, Pattern: artist.NewUniform(hex(0x8D9894FF)) },
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x7f8c89FF)) })
+var pressedSelectedScrollBarPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: strokePattern },
+	artist.Stroke {
+		Weight: 1,
+		Pattern: artist.Beveled {
+			artist.NewUniform(hex(0xCCD5D2FF)),
+			artist.NewUniform(hex(0x4B5B59FF)),
+		},
+	},
+	artist.Stroke { Weight: 1, Pattern: accentPattern },
+	artist.Stroke { Pattern: artist.NewUniform(hex(0x7f8c89FF)) })
+var disabledScrollBarPattern = artist.NewMultiBordered (
+	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
+	artist.Stroke { Pattern: backgroundPattern })

theme/input.go

@@ -1,21 +0,0 @@
-package theme
-
-import "git.tebibyte.media/sashakoshka/tomo/artist"
-
-var inputPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0x89925AFF)),
-			artist.NewUniform(hex(0xD2CB9AFF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0xD2CB9AFF)) })
-var selectedInputPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke { Weight: 1, Pattern: accentPattern },
-	artist.Stroke { Pattern: artist.NewUniform(hex(0xD2CB9AFF)) })
-var disabledInputPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
-	artist.Stroke { Pattern: backgroundPattern })

theme/inset.go

@@ -0,0 +1,42 @@
+package theme
+
+import "image"
+
+// Inset represents an inset amount for all four sides of a rectangle. The top
+// side is at index zero, the right at index one, the bottom at index two, and
+// the left at index three. These values may be negative.
+type Inset [4]int
+
+// Apply returns the given rectangle, shrunk on all four sides by the given
+// inset. If a measurment of the inset is negative, that side will instead be
+// expanded outward. If the rectangle's dimensions cannot be reduced any
+// further, an empty rectangle near its center will be returned.
+func (inset Inset) Apply (bigger image.Rectangle) (smaller image.Rectangle) {
+	smaller = bigger
+	if smaller.Dx() < inset[3] + inset[1] {
+		smaller.Min.X = (smaller.Min.X + smaller.Max.X) / 2
+		smaller.Max.X = smaller.Min.X
+	} else {
+		smaller.Min.X += inset[3]
+		smaller.Max.X -= inset[1]
+	}
+
+	if smaller.Dy() < inset[0] + inset[2] {
+		smaller.Min.Y = (smaller.Min.Y + smaller.Max.Y) / 2
+		smaller.Max.Y = smaller.Min.Y
+	} else {
+		smaller.Min.Y += inset[0]
+		smaller.Max.Y -= inset[2]
+	}
+	return
+}
+
+// Inverse returns a negated version of the inset.
+func (inset Inset) Inverse () (prime Inset) {
+	return Inset {
+		inset[0] * -1,
+		inset[1] * -1,
+		inset[2] * -1,
+		inset[3] * -1,
+	}
+}

theme/list.go

@@ -1,43 +0,0 @@
-package theme
-
-import "git.tebibyte.media/sashakoshka/tomo/artist"
-
-var listPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			uhex(0x383C3AFF),
-			uhex(0x999C99FF),
-		},
-	},
-	artist.Stroke { Pattern: uhex(0x999C99FF) })
-
-var focusedListPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke { Weight: 1, Pattern: accentPattern },
-	artist.Stroke { Pattern: uhex(0x999C99FF) })
-
-var listEntryPattern = artist.Padded {
-	Stroke: uhex(0x383C3AFF),
-	Fill:   uhex(0x999C99FF),
-	Sides:  []int { 0, 0, 0, 1 },
-}
-
-var onListEntryPattern = artist.Padded {
-	Stroke: uhex(0x383C3AFF),
-	Fill:   uhex(0x6e8079FF),
-	Sides:  []int { 0, 0, 0, 1 },
-}
-
-var focusedListEntryPattern = artist.Padded {
-	Stroke: accentPattern,
-	Fill:   uhex(0x999C99FF),
-	Sides:  []int { 0, 1, 0, 1 },
-}
-
-var focusedOnListEntryPattern = artist.Padded {
-	Stroke: accentPattern,
-	Fill:   uhex(0x6e8079FF),
-	Sides:  []int { 0, 1, 0, 1 },
-}

theme/parse.go

@@ -0,0 +1,9 @@
+package theme
+
+import "io"
+
+// Parse parses one or more theme files and returns them as a Theme.
+func Parse (sources ...io.Reader) (Theme) {
+	// TODO
+	return Default { }
+}

theme/patterns.go

@@ -1,239 +0,0 @@
-package theme
-
-import "image"
-import "git.tebibyte.media/sashakoshka/tomo/artist"
-
-// Case sepecifies what kind of element is using a pattern. It contains a
-// namespace parameter and an element parameter. The element parameter does not
-// necissarily need to match an element name, but if it can, it should. Both
-// parameters should be written in camel case. Themes can change their styling
-// based on this parameter for fine-grained control over the look and feel of
-// specific elements.
-type Case struct { Namespace, Element string } 
- 
-// C can be used as shorthand to generate a case struct as used in PatternState.
-func C (namespace, element string) (c Case) {
-	return Case {
-		Namespace: namespace,
-		Element: element,
-	}
-}
-
-// PatternState lists parameters which can change the appearance of some
-// patterns. For example, passing a PatternState with Selected set to true may
-// result in a pattern that has a colored border within it.
-type PatternState struct {
-	Case
-
-	// On should be set to true if the element that is using this pattern is
-	// in some sort of "on" state, such as if a checkbox is checked or a
-	// switch is toggled on. This is only necessary if the element in
-	// question is capable of being toggled.
-	On bool
-
-	// Focused should be set to true if the element that is using this
-	// pattern is currently focused.
-	Focused bool
-
-	// Pressed should be set to true if the element that is using this
-	// pattern is being pressed down by the mouse. This is only necessary if
-	// the element in question processes mouse button events.
-	Pressed bool
-
-	// Disabled should be set to true if the element that is using this
-	// pattern is locked and cannot be interacted with. Disabled variations
-	// of patterns are typically flattened and greyed-out.
-	Disabled bool
-
-	// Invalid should be set to true if th element that is using this
-	// pattern wants to warn the user of an invalid interaction or data
-	// entry. Invalid variations typically have some sort of reddish tint
-	// or outline.
-	Invalid bool
-}
-
-// Inset represents an inset amount for all four sides of a rectangle. The top
-// side is at index zero, the right at index one, the bottom at index two, and
-// the left at index three. These values may be negative.
-type Inset [4]int
-
-// Apply returns the given rectangle, shrunk on all four sides by the given
-// inset. If a measurment of the inset is negative, that side will instead be
-// expanded outward. If the rectangle's dimensions cannot be reduced any
-// further, an empty rectangle near its center will be returned.
-func (inset Inset) Apply (bigger image.Rectangle) (smaller image.Rectangle) {
-	smaller = bigger
-	if smaller.Dx() < inset[3] + inset[1] {
-		smaller.Min.X = (smaller.Min.X + smaller.Max.X) / 2
-		smaller.Max.X = smaller.Min.X
-	} else {
-		smaller.Min.X += inset[3]
-		smaller.Max.X -= inset[1]
-	}
-
-	if smaller.Dy() < inset[0] + inset[2] {
-		smaller.Min.Y = (smaller.Min.Y + smaller.Max.Y) / 2
-		smaller.Max.Y = smaller.Min.Y
-	} else {
-		smaller.Min.Y += inset[0]
-		smaller.Max.Y -= inset[2]
-	}
-	return
-}
-
-// Inverse returns a negated version of the inset.
-func (inset Inset) Inverse () (prime Inset) {
-	return Inset {
-		inset[0] * -1,
-		inset[1] * -1,
-		inset[2] * -1,
-		inset[3] * -1,
-	}
-}
-
-// AccentPattern returns the accent pattern, which is usually just a solid
-// color.
-func AccentPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	return accentPattern, Inset { }
-}
-
-// BackgroundPattern returns the main background pattern.
-func BackgroundPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	return backgroundPattern, Inset { }
-}
-
-// DeadPattern returns a pattern that can be used to mark an area or gap that
-// serves no purpose, but still needs aesthetic structure.
-func DeadPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	return deadPattern, Inset { }
-}
-
-// ForegroundPattern returns the color text should be.
-func ForegroundPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Disabled {
-		return weakForegroundPattern, Inset { }
-	} else {
-		return foregroundPattern, Inset { }
-	}
-}
-
-// InputPattern returns a background pattern for any input field that can be
-// edited by typing with the keyboard.
-func InputPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Disabled {
-		return disabledInputPattern, Inset { 1, 1, 1, 1 }
-	} else {
-		if state.Focused {
-			return selectedInputPattern, Inset { 1, 1, 1, 1 }
-		} else {
-			return inputPattern, Inset { 1, 1, 1, 1 }
-		}
-	}
-}
-
-// ListPattern returns a background pattern for a list of things.
-func ListPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Focused {
-		pattern = focusedListPattern
-		inset = Inset { 2, 1, 2, 1 }
-	} else {
-		pattern = listPattern
-		inset = Inset { 2, 1, 1, 1 }
-	}
-	return
-}
-
-// ItemPattern returns a background pattern for a list item.
-func ItemPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Focused {
-		if state.On {
-			pattern = focusedOnListEntryPattern
-		} else {
-			pattern = focusedListEntryPattern
-		}
-	} else {
-		if state.On {
-			pattern = onListEntryPattern
-		} else {
-			pattern = listEntryPattern
-		}
-	}
-	inset = Inset { 4, 6, 4, 6 }
-	return
-}
-
-// ButtonPattern returns a pattern to be displayed on buttons.
-func ButtonPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Disabled {
-		return disabledButtonPattern, Inset { 1, 1, 1, 1 }
-	} else {
-		if state.Pressed {
-			if state.Focused {
-				return pressedSelectedButtonPattern, Inset {
-					2, 0, 0, 2 }
-			} else {
-				return pressedButtonPattern, Inset { 2, 0, 0, 2 }
-			}
-		} else {
-			if state.Focused {
-				return selectedButtonPattern, Inset { 1, 1, 1, 1 }
-			} else {
-				return buttonPattern, Inset { 1, 1, 1, 1 }
-			}
-		}
-	}
-}
-
-// GutterPattern returns a pattern to be used to mark a track along which
-// something slides.
-func GutterPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Disabled {
-		return disabledScrollGutterPattern, Inset { 0, 0, 0, 0 }
-	} else {
-		return scrollGutterPattern, Inset { 0, 0, 0, 0 }
-	}
-}
-
-// HandlePattern returns a pattern to be displayed on a grab handle that slides
-// along a gutter.
-func HandlePattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Disabled {
-		return disabledScrollBarPattern, Inset { 1, 1, 1, 1 }
-	} else {
-		if state.Focused {
-			if state.Pressed {
-				return pressedSelectedScrollBarPattern, Inset { 1, 1, 1, 1 }
-			} else {
-				return selectedScrollBarPattern, Inset { 1, 1, 1, 1 }
-			}
-		} else {
-			if state.Pressed {
-				return pressedScrollBarPattern, Inset { 1, 1, 1, 1 }
-			} else {
-				return scrollBarPattern, Inset { 1, 1, 1, 1 }
-			}
-		}
-	}
-}
-
-// SunkenPattern returns a general purpose pattern that is sunken/engraved into
-// the background.
-func SunkenPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	return sunkenPattern, Inset { 1, 1, 1, 1 }
-}
-
-// RaisedPattern returns a general purpose pattern that is raised up out of the
-// background.
-func RaisedPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	if state.Focused {
-		return selectedRaisedPattern, Inset { 1, 1, 1, 1 }
-	} else {
-		return raisedPattern, Inset { 1, 1, 1, 1 }
-	}
-}
-
-// PinboardPattern returns a textured backdrop pattern. Anything drawn within it
-// should have its own background pattern.
-func PinboardPattern (state PatternState) (pattern artist.Pattern, inset Inset) {
-	return texturedSunkenPattern, Inset { 1, 1, 1, 1 }
-}

theme/scroll.go

@@ -1,63 +0,0 @@
-package theme
-
-import "git.tebibyte.media/sashakoshka/tomo/artist"
-
-var scrollGutterPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0x3b534eFF)),
-			artist.NewUniform(hex(0x6e8079FF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x6e8079FF)) })
-var disabledScrollGutterPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
-	artist.Stroke { Pattern: backgroundPattern })
-var scrollBarPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xCCD5D2FF)),
-			artist.NewUniform(hex(0x4B5B59FF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
-var selectedScrollBarPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xCCD5D2FF)),
-			artist.NewUniform(hex(0x4B5B59FF)),
-		},
-	},
-	artist.Stroke { Weight: 1, Pattern: accentPattern },
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x8D9894FF)) })
-var pressedScrollBarPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xCCD5D2FF)),
-			artist.NewUniform(hex(0x4B5B59FF)),
-		},
-	},
-	artist.Stroke { Weight: 1, Pattern: artist.NewUniform(hex(0x8D9894FF)) },
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x7f8c89FF)) })
-var pressedSelectedScrollBarPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xCCD5D2FF)),
-			artist.NewUniform(hex(0x4B5B59FF)),
-		},
-	},
-	artist.Stroke { Weight: 1, Pattern: accentPattern },
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x7f8c89FF)) })
-var disabledScrollBarPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: weakForegroundPattern },
-	artist.Stroke { Pattern: backgroundPattern })

theme/state.go

@@ -0,0 +1,78 @@
+package theme
+
+// Case sepecifies what kind of element is using a pattern. It contains a
+// namespace parameter and an element parameter. The element parameter does not
+// necissarily need to match an element name, but if it can, it should. Both
+// parameters should be written in camel case. Themes can change their styling
+// based on this parameter for fine-grained control over the look and feel of
+// specific elements.
+type Case struct { Namespace, Element string } 
+ 
+// C can be used as shorthand to generate a case struct as used in PatternState.
+func C (namespace, element string) (c Case) {
+	return Case {
+		Namespace: namespace,
+		Element: element,
+	}
+}
+
+// PatternState lists parameters which can change the appearance of some
+// patterns. For example, passing a PatternState with Selected set to true may
+// result in a pattern that has a colored border within it.
+type PatternState struct {
+	// On should be set to true if the element that is using this pattern is
+	// in some sort of "on" state, such as if a checkbox is checked or a
+	// switch is toggled on. This is only necessary if the element in
+	// question is capable of being toggled.
+	On bool
+
+	// Focused should be set to true if the element that is using this
+	// pattern is currently focused.
+	Focused bool
+
+	// Pressed should be set to true if the element that is using this
+	// pattern is being pressed down by the mouse. This is only necessary if
+	// the element in question processes mouse button events.
+	Pressed bool
+
+	// Disabled should be set to true if the element that is using this
+	// pattern is locked and cannot be interacted with. Disabled variations
+	// of patterns are typically flattened and greyed-out.
+	Disabled bool
+
+	// Invalid should be set to true if th element that is using this
+	// pattern wants to warn the user of an invalid interaction or data
+	// entry. Invalid variations typically have some sort of reddish tint
+	// or outline.
+	Invalid bool
+}
+
+// FontStyle specifies stylistic alterations to a font face.
+type FontStyle int; const (
+	FontStyleRegular    FontStyle = 0
+	FontStyleBold       FontStyle = 1
+	FontStyleItalic     FontStyle = 2
+	FontStyleBoldItalic FontStyle = 1 | 2
+)
+
+// FontSize specifies the general size of a font face in a semantic way.
+type FontSize int; const (
+	// FontSizeNormal is the default font size that should be used for most
+	// things.
+	FontSizeNormal FontSize = iota
+
+	// FontSizeLarge is a larger font size suitable for things like section
+	// headings.
+	FontSizeLarge
+
+	// FontSizeHuge is a very large font size suitable for things like
+	// titles, wizard step names, digital clocks, etc.
+	FontSizeHuge
+
+	// FontSizeSmall is a smaller font size. Try not to use this unless it
+	// makes a lot of sense to do so, because it can negatively impact
+	// accessibility. It is useful for things like copyright notices at the
+	// bottom of some window that the average user doesn't actually care
+	// about.
+	FontSizeSmall
+)

theme/theme.go

@@ -1,113 +1,116 @@
 package theme
 
-import "image/color"
+import "image"
 import "golang.org/x/image/font"
 import "git.tebibyte.media/sashakoshka/tomo/artist"
-import "git.tebibyte.media/sashakoshka/tomo/defaultfont"
 
-// none of these colors are final! TODO: generate these values from a theme
+// Pattern lists a number of cannonical pattern types, each with its own ID.
-// file at startup.
+// This allows custom elements to follow themes, even those that do not
+// explicitly support them.
+type Pattern int; const (
+	// PatternAccent is the accent color of the theme. It is safe to assume
+	// that this is, by default, a solid color.
+	PatternAccent Pattern = iota
 
-func hex (color uint32) (c color.RGBA) {
+	// PatternBackground is the background color of the theme. It is safe to
-	c.A = uint8(color)
+	// assume that this is, by default, a solid color.
-	c.B = uint8(color >>  8)
+	PatternBackground
-	c.G = uint8(color >> 16)
+
-	c.R = uint8(color >> 24)
+	// PatternForeground is the foreground text color of the theme. It is
+	// safe to assume that this is, by default, a solid color.
+	PatternForeground
+
+	// PatternDead is a pattern that is displayed on a "dead area" where no
+	// controls exist, but there still must be some indication of visual
+	// structure (such as in the corner between two scroll bars).
+	PatternDead
+
+	// PatternRaised is a generic raised pattern.
+	PatternRaised
+
+	// PatternSunken is a generic sunken pattern.
+	PatternSunken
+
+	// PatternPinboard is similar to PatternSunken, but it is textured.
+	PatternPinboard
+
+	// PatternButton is a button pattern.
+	PatternButton
+
+	// PatternInput is a pattern for input fields, editable text areas, etc.
+	PatternInput
+
+	// PatternGutter is a track for things to slide on.
+	PatternGutter
+
+	// PatternHandle is a handle that slides along a gutter.
+	PatternHandle
+)
+
+// Theme represents a visual style configuration,
+type Theme interface {
+	// FontFace returns the proper font for a given style, size, and case.
+	FontFace (FontStyle, FontSize, Case) font.Face
+
+	// Icon returns an appropriate icon given an icon name and case.
+	Icon (string, Case) artist.Pattern
+
+	// Pattern returns an appropriate pattern given a pattern name, case,
+	// and state.
+	Pattern (Pattern, Case, PatternState) artist.Pattern
+
+	// Inset returns the area on all sides of a given pattern that is not
+	// meant to be drawn on.
+	Inset (Pattern, Case) Inset
+
+	// Sink returns a vector that should be added to an element's inner
+	// content when it is pressed down (if applicable) to simulate a 3D
+	// sinking effect.
+	Sink (Pattern, Case) image.Point
+}
+
+// Wrapped wraps any theme and injects a case into it automatically so that it
+// doesn't need to be specified for each query. Additionally, if the underlying
+// theme is nil, it just uses the default theme instead.
+type Wrapped struct {
+	Theme
+	Case
+}
+
+// FontFace returns the proper font for a given style and size.
+func (wrapped Wrapped) FontFace (style FontStyle, size FontSize) font.Face {
+	real := wrapped.ensure()
+	return real.FontFace(style, size, wrapped.Case)
+}
+
+// Icon returns an appropriate icon given an icon name.
+func (wrapped Wrapped) Icon (name string) artist.Pattern {
+	real := wrapped.ensure()
+	return real.Icon(name, wrapped.Case)
+}
+
+// Pattern returns an appropriate pattern given a pattern name and state.
+func (wrapped Wrapped) Pattern (id Pattern, state PatternState) artist.Pattern {
+	real := wrapped.ensure()
+	return real.Pattern(id, wrapped.Case, state)
+}
+
+// Inset returns the area on all sides of a given pattern that is not meant to
+// be drawn on.
+func (wrapped Wrapped) Inset (id Pattern) Inset {
+	real := wrapped.ensure()
+	return real.Inset(id, wrapped.Case)
+}
+
+// Sink returns a vector that should be added to an element's inner content when
+// it is pressed down (if applicable) to simulate a 3D sinking effect.
+func (wrapped Wrapped) Sink (id Pattern) image.Point {
+	real := wrapped.ensure()
+	return real.Sink(id, wrapped.Case)
+}
+
+func (wrapped Wrapped) ensure () (real Theme) {
+	real = wrapped.Theme
+	if real == nil { real = Default { } }
 	return
 }
-
-func uhex (color uint32) (pattern artist.Pattern) {
-	return artist.NewUniform(hex(color))
-}
-
-var accentPattern         = artist.NewUniform(hex(0x408090FF))
-var backgroundPattern     = artist.NewUniform(color.Gray16 { 0xAAAA })
-var foregroundPattern     = artist.NewUniform(color.Gray16 { 0x0000 })
-var weakForegroundPattern = artist.NewUniform(color.Gray16 { 0x4444 })
-var strokePattern         = artist.NewUniform(color.Gray16 { 0x0000 })
-
-var sunkenPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0x3b534eFF)),
-			artist.NewUniform(hex(0x97a09cFF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x97a09cFF)) })
-
-var texturedSunkenPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0x3b534eFF)),
-			artist.NewUniform(hex(0x97a09cFF)),
-		},
-	},
-	// artist.Stroke { Pattern: artist.Striped {
-		// First: artist.Stroke {
-			// Weight: 2,
-			// Pattern: artist.NewUniform(hex(0x97a09cFF)),
-		// },
-		// Second: artist.Stroke {
-			// Weight: 1,
-			// Pattern: artist.NewUniform(hex(0x6e8079FF)),
-		// },
-	// }})
-	
-	artist.Stroke { Pattern: artist.Noisy {
-		Low:  artist.NewUniform(hex(0x97a09cFF)),
-		High: artist.NewUniform(hex(0x6e8079FF)),
-	}})
-
-var raisedPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xDBDBDBFF)),
-			artist.NewUniform(hex(0x383C3AFF)),
-		},
-	},
-	artist.Stroke { Pattern: artist.NewUniform(hex(0xAAAAAAFF)) })
-
-var selectedRaisedPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke {
-		Weight: 1,
-		Pattern: artist.Beveled {
-			artist.NewUniform(hex(0xDBDBDBFF)),
-			artist.NewUniform(hex(0x383C3AFF)),
-		},
-	},
-	artist.Stroke { Weight: 1, Pattern: accentPattern },
-	artist.Stroke { Pattern: artist.NewUniform(hex(0xAAAAAAFF)) })
-
-var deadPattern = artist.NewMultiBordered (
-	artist.Stroke { Weight: 1, Pattern: strokePattern },
-	artist.Stroke { Pattern: artist.NewUniform(hex(0x97a09cFF)) })
-
-// TODO: load fonts from an actual source instead of using defaultfont
-
-// FontFaceRegular returns the font face to be used for normal text.
-func FontFaceRegular () font.Face {
-	return defaultfont.FaceRegular
-}
-
-// FontFaceBold returns the font face to be used for bolded text.
-func FontFaceBold () font.Face {
-	return defaultfont.FaceBold
-}
-
-// FontFaceItalic returns the font face to be used for italicized text.
-func FontFaceItalic () font.Face {
-	return defaultfont.FaceItalic
-}
-
-// FontFaceBoldItalic returns the font face to be used for text that is both
-// bolded and italicized.
-func FontFaceBoldItalic () font.Face {
-	return defaultfont.FaceBoldItalic
-}

theme/util.go

@@ -0,0 +1,16 @@
+package theme
+
+import "image/color"
+import "git.tebibyte.media/sashakoshka/tomo/artist"
+
+func hex (color uint32) (c color.RGBA) {
+	c.A = uint8(color)
+	c.B = uint8(color >>  8)
+	c.G = uint8(color >> 16)
+	c.R = uint8(color >> 24)
+	return
+}
+
+func uhex (color uint32) (pattern artist.Pattern) {
+	return artist.NewUniform(hex(color))
+}

tomo.go

@@ -1,7 +1,12 @@
 package tomo
 
-import "errors"
+import "os"
+import "io"
+import "path/filepath"
+import "git.tebibyte.media/sashakoshka/tomo/dirs"
 import "git.tebibyte.media/sashakoshka/tomo/data"
+import "git.tebibyte.media/sashakoshka/tomo/theme"
+import "git.tebibyte.media/sashakoshka/tomo/config"
 import "git.tebibyte.media/sashakoshka/tomo/elements"
 
 var backend Backend
@@ -11,6 +16,9 @@ var backend Backend
 // the backend experiences a fatal error.
 func Run (callback func ()) (err error) {
 	backend, err = instantiateBackend()
+	config := parseConfig()
+	backend.SetConfig(config)
+	backend.SetTheme(parseTheme(config.ThemePath()))
 	if callback != nil { callback() }
 	err = backend.Run()
 	backend = nil
@@ -26,7 +34,7 @@ func Stop () {
 // Do executes the specified callback within the main thread as soon as
 // possible. This function can be safely called from other threads.
 func Do (callback func ()) {
-	if backend == nil { panic("no backend is running") }
+	assertBackend()
 	backend.Do(callback)
 }
 
@@ -35,22 +43,87 @@ func Do (callback func ()) {
 // why. If this function is called without a running backend, an error is
 // returned as well.
 func NewWindow (width, height int) (window elements.Window, err error) {
-	if backend == nil {
+	assertBackend()
-		err = errors.New("no backend is running.")
-		return
-	}
 	return backend.NewWindow(width, height)
 }
 
 // Copy puts data into the clipboard.
 func Copy (data data.Data) {
-	if backend == nil { panic("no backend is running") }
+	assertBackend()
 	backend.Copy(data)
 }
 
 // Paste returns the data currently in the clipboard. This method may
 // return nil.
 func Paste (accept []data.Mime) (data.Data) {
-	if backend == nil { panic("no backend is running") }
+	assertBackend()
 	return backend.Paste(accept)
 }
+
+// SetTheme sets the theme of all open windows.
+func SetTheme (theme theme.Theme) {
+	backend.SetTheme(theme)
+}
+
+// SetConfig sets the configuration of all open windows.
+func SetConfig (config config.Config) {
+	backend.SetConfig(config)
+}
+
+func parseConfig () (config.Config) {
+	return parseMany [config.Config] (
+		dirs.ConfigDirs("tomo/tomo.conf"),
+		config.Parse,
+		config.Default { })
+}
+
+func parseTheme (path string) (theme.Theme) {
+	if path == "" { return theme.Default { } }
+	path = filepath.Join(path, "tomo")
+	
+	// find all tomo pattern graph files in the directory
+	directory, err := os.Open(path)
+	if err != nil { return theme.Default { } }
+	names, _ := directory.Readdirnames(0)
+	paths := []string { }
+	for _, name := range names {
+		if filepath.Ext(name) == ".tpg" {
+			paths = append(paths, filepath.Join(path, name))
+		}
+	}
+
+	// parse them
+	return parseMany [theme.Theme] (
+		paths,
+		theme.Parse,
+		theme.Default { })
+}
+
+func parseMany [OBJECT any] (
+	paths []string,
+	parser func (...io.Reader) OBJECT,
+	fallback OBJECT,
+) (
+	object OBJECT,
+) {
+	// convert all paths into readers
+	sources := []io.Reader { }
+	for _, path := range paths {
+		file, err := os.Open(path)
+		if err != nil { continue }
+		sources = append(sources, file)
+		defer file.Close()
+	}
+	
+	if sources == nil {
+		// if there are no readers, return the fallback object
+		return fallback
+	} else {
+		// if there are readers, parse them
+		return parser(sources...)
+	}
+}
+
+func assertBackend () {
+	if backend == nil { panic("no backend is running") }
+}