Add more xdg stuff

The code has also been reorganized and cleaned up a bit, with more
comments added.

backends/x/encoding.go

@@ -1,8 +1,5 @@
 package x
 
-// TODO: rename this file? lol
-
-// import "fmt"
 import "unicode"
 import "github.com/jezek/xgb/xproto"
 import "github.com/jezek/xgbutil/keybind"
@@ -112,6 +109,10 @@ var keypadCodeTable = map[xproto.Keysym] stone.Button {
 	0xffb9: stone.Button('9'),
 }
 
+// keycodeToButton converts an X keycode to a stone button code. It implements
+// a more fleshed out version of some of the logic found in
+// xgbutil/keybind/encoding.go to get a full keycode to keysym conversion, but
+// eliminates redundant work by going straight to a button code.
 func (backend *Backend) keycodeToButton (
 	keycode xproto.Keycode,
 	state   uint16,
@@ -119,19 +120,6 @@ func (backend *Backend) keycodeToButton (
 	button    stone.Button,
 	numberPad bool,
 ) {
-	shift :=
-		state & xproto.ModMaskShift             > 0 ||
-		state & backend.modifierMasks.shiftLock > 0
-	capsLock := state & backend.modifierMasks.capsLock  > 0
-	numLock  := state & backend.modifierMasks.numLock   > 0
-
-	symbol1 := keybind.KeysymGet(backend.connection, keycode, 0)
-	symbol2 := keybind.KeysymGet(backend.connection, keycode, 1)
-	symbol3 := keybind.KeysymGet(backend.connection, keycode, 2)
-	symbol4 := keybind.KeysymGet(backend.connection, keycode, 3)
-
-	cased := false
-
 	// PARAGRAPH 3
 	//
 	// A list of KeySyms is associated with each KeyCode. The list is
@@ -145,6 +133,10 @@ func (backend *Backend) keycodeToButton (
 	// treated as if it were the list ``K1 K2 K3 NoSymbol''. When an
 	// explicit ``void'' element is desired in the list, the value
 	// VoidSymbol can be used.
+	symbol1 := keybind.KeysymGet(backend.connection, keycode, 0)
+	symbol2 := keybind.KeysymGet(backend.connection, keycode, 1)
+	symbol3 := keybind.KeysymGet(backend.connection, keycode, 2)
+	symbol4 := keybind.KeysymGet(backend.connection, keycode, 3)
 	switch {
 	case symbol2 == 0 && symbol3 == 0 && symbol4 == 0:
 		symbol3 = symbol1
@@ -154,15 +146,11 @@ func (backend *Backend) keycodeToButton (
 	case symbol4 == 0:
 		symbol4 = 0
 	}
-
 	symbol1Rune := keysymToRune(symbol1)
 	symbol2Rune := keysymToRune(symbol2)
 	symbol3Rune := keysymToRune(symbol3)
 	symbol4Rune := keysymToRune(symbol4)
 
-	// FIXME: we ignore mode switch stuff
-	_ = symbol4Rune
-
 	// PARAGRAPH 4
 	//
 	// The first four elements of the list are split into two groups of
@@ -175,6 +163,7 @@ func (backend *Backend) keycodeToButton (
 	// group should be treated as if the first element were the lowercase
 	// form of ``K'' and the second element were the uppercase form of
 	// ``K.''
+	cased := false
 	if symbol2 == 0 {
 		upper := unicode.IsUpper(symbol1Rune)
 		lower := unicode.IsLower(symbol1Rune)
@@ -200,15 +189,59 @@ func (backend *Backend) keycodeToButton (
 		}
 	}
 
-	var selectedKeysym xproto.Keysym
-	var selectedRune   rune
+	// PARAGRAPH 5
+	//
+	// The standard rules for obtaining a KeySym from a KeyPress event make
+	// use of only the Group 1 and Group 2 KeySyms; no interpretation of/
+	// other KeySyms in the list is given. Which group to use is determined
+	// by the modifier state. Switching between groups is controlled by the
+	// KeySym named MODE SWITCH, by attaching that KeySym to some KeyCode
+	// and attaching that KeyCode to any one of the modifiers Mod1 through
+	// Mod5. This modifier is called the group modifier. For any KeyCode,
+	// Group 1 is used when the group modifier is off, and Group 2 is used
+	// when the group modifier is on.
+	modeSwitch := state & backend.modifierMasks.modeSwitch > 0
+	if modeSwitch {
+		symbol1     = symbol3
+		symbol1Rune = symbol3Rune
+		symbol2     = symbol4
+		symbol2Rune = symbol4Rune
+		
+	}
 	
-	_, symbol2IsNumPad := keypadCodeTable[symbol2]
+	// PARAGRAPH 6
+	// 
+	// The Lock modifier is interpreted as CapsLock when the KeySym named
+	// XK_Caps_Lock is attached to some KeyCode and that KeyCode is attached
+	// to the Lock modifier. The Lock modifier is interpreted as ShiftLock
+	// when the KeySym named XK_Shift_Lock is attached to some KeyCode and
+	// that KeyCode is attached to the Lock modifier. If the Lock modifier
+	// could be interpreted as both CapsLock and ShiftLock, the CapsLock
+	// interpretation is used.
+	shift :=
+		state & xproto.ModMaskShift                > 0 ||
+		state & backend.modifierMasks.shiftLock    > 0
+	capsLock := state & backend.modifierMasks.capsLock > 0
 
-	// "PARAGRAPH" 5
+	// PARAGRAPH 7
+	//
+	// The operation of keypad keys is controlled by the KeySym named
+	// XK_Num_Lock, by attaching that KeySym to some KeyCode and attaching
+	// that KeyCode to any one of the modifiers Mod1 through Mod5 . This
+	// modifier is called the numlock modifier. The standard KeySyms with
+	// the prefix ``XK_KP_'' in their name are called keypad KeySyms; these
+	// are KeySyms with numeric value in the hexadecimal range 0xFF80 to
+	// 0xFFBD inclusive. In addition, vendor-specific KeySyms in the
+	// hexadecimal range 0x11000000 to 0x1100FFFF are also keypad KeySyms.
+	numLock  := state & backend.modifierMasks.numLock  > 0
+	
+	// PARAGRAPH 8
 	//
 	// Within a group, the choice of KeySym is determined by applying the
 	// first rule that is satisfied from the following list:
+	var selectedKeysym xproto.Keysym
+	var selectedRune   rune
+	_, symbol2IsNumPad := keypadCodeTable[symbol2]
 	switch {
 	case numLock && symbol2IsNumPad:
 		// The numlock modifier is on and the second KeySym is a keypad
@@ -261,6 +294,10 @@ func (backend *Backend) keycodeToButton (
 		selectedRune   = symbol2Rune
 	}
 
+	/////////////////////////////////////////////////////////////////
+	// all of the below stuff is specific to stone's button codes. //
+	/////////////////////////////////////////////////////////////////
+
 	// look up in control code table
 	var isControl bool
 	button, isControl = buttonCodeTable[selectedKeysym]
@@ -276,6 +313,9 @@ func (backend *Backend) keycodeToButton (
 	return
 }
 
+// keysymToRune takes in an X keysym and outputs a utf32 code point. This
+// function does not and should not handle keypad keys, as those are handled
+// by Backend.keycodeToButton.
 func keysymToRune (keysym xproto.Keysym) (character rune) {
 	// X keysyms like 0xFF.. or 0xFE.. are non-character keys. these cannot
 	// be converted so we return a zero.

buffer.go

@@ -192,9 +192,13 @@ func (buffer *DamageBuffer) Write (bytes []byte) (bytesWritten int, err error) {
 	bytesWritten = len(bytes)
 	
 	for _, character := range text {
-		buffer.setRune(buffer.dot.x, buffer.dot.y, character)
-		buffer.dot.x ++
-		if buffer.dot.x > buffer.width { break }
+		if character == '\n' {
+			buffer.dot.x = 0
+			buffer.dot.y ++
+		} else {
+			buffer.setRune(buffer.dot.x, buffer.dot.y, character)
+			buffer.dot.x ++
+		}
 	}
 	
 	return

config.go

@@ -1,15 +1,13 @@
 package stone
 
-import "os"
-import "bufio"
-import "strings"
-import "strconv"
 import "image/color"
-import "path/filepath"
 
-// Config stores configuration parameters. Backends only should honor parameters
-// that they can support.
+import "git.tebibyte.media/sashakoshka/stone/config"
+
+// Config stores global, read-only configuration parameters that apply to all
+// applications. Backends only should honor parameters that they can support.
 type Config struct {
+	private  config.Config
 	colors   [8]color.Color
 	padding  int
 	center   bool
@@ -18,154 +16,94 @@ type Config struct {
 }
 
 // Color returns the color value at the specified index.
-func (config *Config) Color (index Color) (value color.Color) {
-	value = config.colors[index]
+func (public *Config) Color (index Color) (value color.Color) {
+	value = public.colors[index]
 	return
 }
 
 // Padding specifies how many cell's worth of padding should be on all sides of
 // the buffer.
-func (config *Config) Padding () (padding int) {
-	padding = config.padding
+func (public *Config) Padding () (padding int) {
+	padding = public.padding
 	return
 }
 
 // Center returns whether the buffer should be displayed in the center of the
 // window like in kitty, or aligned to one corner like in gnome-terminal.
-func (config *Config) Center () (center bool) {
-	center = config.center
+func (public *Config) Center () (center bool) {
+	center = public.center
 	return
 }
 
 // FontSize specifies how big the font should be.
-func (config *Config) FontSize () (fontSize int) {
-	fontSize = config.fontSize
+func (public *Config) FontSize () (fontSize int) {
+	fontSize = public.fontSize
 	return
 }
 
 // FontName specifies the name of the font to use.
-func (config *Config) FontName () (fontName string) {
-	fontName = config.fontName
+func (public *Config) FontName () (fontName string) {
+	fontName = public.fontName
 	return
 }
 
-func (config *Config) load () {
-	config.colors = [8]color.Color {
-		// background
-		color.RGBA { R: 0, G: 0, B: 0, A: 0 },
-		// foreground
-		color.RGBA { R: 0xFF, G: 0xFF, B: 0xFF, A: 0xFF },
-		// dim
-		color.RGBA { R: 0x80, G: 0x80, B: 0x80, A: 0xFF },
-		// red
-		color.RGBA { R: 0xFF, G: 0x00, B: 0x00, A: 0xFF },
-		// yellow
-		color.RGBA { R: 0xFF, G: 0xFF, B: 0x00, A: 0xFF },
-		// green
-		color.RGBA { R: 0x00, G: 0xFF, B: 0x00, A: 0xFF },
-		// blue
-		color.RGBA { R: 0x00, G: 0x80, B: 0xFF, A: 0xFF },
-		// purple
-		color.RGBA { R: 0x80, G: 0x40, B: 0xFF, A: 0xFF },
+func (public *Config) load () {
+	public.private = config.Config {
+		LegalParameters: map[string] config.Type {
+			"fontNormal":      config.TypeString,
+			"fontSize":        config.TypeInteger,
+			"padding":         config.TypeInteger,
+			"center":          config.TypeBoolean,
+			"colorBackground": config.TypeColor,
+			"colorForeground": config.TypeColor,
+			"colorDim":        config.TypeColor,
+			"colorRed":        config.TypeColor,
+			"colorYellow":     config.TypeColor,
+			"colorGreen":      config.TypeColor,
+			"colorBlue":       config.TypeColor,
+			"colorPurple":     config.TypeColor,
+		},
+		
+		Parameters: map[string] any {
+			"fontNormal": "",
+			"fontSize":   11,
+			"padding":    2,
+			"center":     false,
+			"colorBackground":
+				color.RGBA { R: 0, G: 0, B: 0, A: 0 },
+			"colorForeground":
+				color.RGBA { R: 0xFF, G: 0xFF, B: 0xFF, A: 0xFF },
+			"colorDim":
+				color.RGBA { R: 0x80, G: 0x80, B: 0x80, A: 0xFF },
+			"colorRed":
+				color.RGBA { R: 0xFF, G: 0x00, B: 0x00, A: 0xFF },
+			"colorYellow":
+				color.RGBA { R: 0xFF, G: 0xFF, B: 0x00, A: 0xFF },
+			"colorGreen":
+				color.RGBA { R: 0x00, G: 0xFF, B: 0x00, A: 0xFF },
+			"colorBlue":
+				color.RGBA { R: 0x00, G: 0x80, B: 0xFF, A: 0xFF },
+			"colorPurple":
+				color.RGBA { R: 0x80, G: 0x40, B: 0xFF, A: 0xFF },
+		},
 	}
-	config.fontName = ""
-	config.fontSize = 11
-	config.padding = 2
 
-	config.loadFile("/etc/stone/stone.conf")
-	homeDirectory, err := os.UserHomeDir()
-	if err != nil { return }
-	config.loadFile(filepath.Join(homeDirectory, "/.config/stone/stone.conf"))
+	public.private.Load("stone")
+	params := public.private.Parameters
+
+	public.fontName = params["fontNormal"].(string)
+	public.fontSize = params["fontSize"].(int)
+	public.padding  = params["padding"].(int)
+	public.center   = params["center"].(bool)
+	
+	public.colors[ColorBackground] = params["colorBackground"].(color.RGBA)
+	public.colors[ColorForeground] = params["colorForeground"].(color.RGBA)
+	public.colors[ColorDim]        = params["colorDim"       ].(color.RGBA)
+	public.colors[ColorRed]        = params["colorRed"       ].(color.RGBA)
+	public.colors[ColorYellow]     = params["colorYellow"    ].(color.RGBA)
+	public.colors[ColorGreen]      = params["colorGreen"     ].(color.RGBA)
+	public.colors[ColorBlue]       = params["colorBlue"      ].(color.RGBA)
+	public.colors[ColorPurple]     = params["colorPurple"    ].(color.RGBA)
 	
 	return
 }
-
-func (config *Config) loadFile (path string) {
-	file, err := os.Open(path)
-	if err != nil { return }
-
-	scanner := bufio.NewScanner(file)
-	for scanner.Scan() {
-		line := strings.TrimSpace(scanner.Text())
-		
-		if len(line) == 0 {
-			continue
-		}
-
-		if line[0] == '#' {
-			continue
-		}
-	
-		key, value, found := strings.Cut(scanner.Text(), ":")
-		if !found {
-			println (
-				"config: error in file", path +
-				": key-value separator missing")
-			println(scanner.Text())
-			continue
-		}
-		key   = strings.TrimSpace(key)
-		value = strings.TrimSpace(value)
-
-		var valueInt int
-		var valueColor color.Color
-		var valueBoolean bool
-		
-		if value == "true" {
-			valueBoolean = true
-		}
-
-		if value[0] == '#' {
-			if len(value) != 7  {
-				println (
-					"config: error in file", path +
-					": malformed color literal")
-				continue
-			}
-
-			colorInt, err := strconv.ParseUint(value[1:7], 16, 24)
-			if err != nil  {
-				println (
-					"config: error in file", path +
-					": malformed color literal")
-				continue
-			}
-
-			valueColor = color.RGBA {
-				R: uint8(colorInt >> 16),
-				G: uint8(colorInt >> 8),
-				B: uint8(colorInt),
-				A: 0xFF,
-			}
-		} else {
-			valueInt, _ = strconv.Atoi(value)
-		}
-
-		switch key {
-		case "fontNormal":
-			config.fontName = value
-		case "fontSize":
-			config.fontSize = valueInt
-		case "padding":
-			config.padding = valueInt
-		case "center":
-			config.center = valueBoolean
-		case "colorBackground":
-			config.colors[ColorBackground] = valueColor
-		case "colorForeground":
-			config.colors[ColorForeground] = valueColor
-		case "colorDim":
-			config.colors[ColorDim] = valueColor
-		case "colorRed":
-			config.colors[ColorRed] = valueColor
-		case "colorYellow":
-			config.colors[ColorYellow] = valueColor
-		case "colorGreen":
-			config.colors[ColorGreen] = valueColor
-		case "colorBlue":
-			config.colors[ColorBlue] = valueColor
-		case "colorPurple":
-			config.colors[ColorPurple] = valueColor
-		}
-	}
-}

config/config.go

@@ -0,0 +1,324 @@
+package config
+
+import "io"
+import "os"
+import "fmt"
+import "sort"
+import "bufio"
+import "strings"
+import "strconv"
+import "image/color"
+import "path/filepath"
+
+// when making changes to this file, look at
+// https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
+
+// Error represents an error that can be returned by functions or methods in
+// this module.
+type Error int
+
+const (
+	// ErrorIllegalName is thrown when an application name contains illegal
+	// characters such as a slash.
+	ErrorIllegalName Error = iota
+
+	// ErrorNoSeparator is thrown when a configuration file has an
+	// incorrectly formatted key-value pair.
+	ErrorNoSeparator
+
+	// ErrorUnknownParameter is thrown when an unknown key is encountered in
+	// a configuration file.
+	ErrorUnknownParameter
+
+	// ErrorWrongColorLength is thrown when a configuration file has a color
+	// literal with a total length unequal to 7.
+	ErrorWrongColorLength
+
+	// ErrorMalformedColorLiteral is thrown when a configuration file has an
+	// improperly formatted color literal, or a color literal was expected
+	// and something else was encountered.
+	ErrorMalformedColorLiteral
+	
+	// ErrorMalformedIntegerLiteral is thrown when a configuration file has
+	// an improperly formatted integer literal, or an integer literal was
+	// expected and something else was encountered.
+	ErrorMalformedIntegerLiteral
+	
+	// ErrorMalformedFloatLiteral is thrown when a configuration file has
+	// an improperly formatted float literal, or a float literal was
+	// expected and something else was encountered.
+	ErrorMalformedFloatLiteral
+)
+
+// Error returns a description of the error.
+func (err Error) Error () (description string) {
+	switch err {
+	case ErrorIllegalName:
+		description = "name contains illegal characters"
+	case ErrorNoSeparator:
+		description = "key:value pair has no separator"
+	case ErrorUnknownParameter:
+		description = "unknown parameter"
+	case ErrorWrongColorLength:
+		description = "color literal has the wrong length"
+	case ErrorMalformedColorLiteral:
+		description = "malformed color literal"
+	case ErrorMalformedIntegerLiteral:
+		description = "malformed integer literal"
+	case ErrorMalformedFloatLiteral:
+		description = "malformed float literal"
+	}
+
+	return
+}
+
+// Type represents the data type of a configuration parameter.
+type Type int
+
+const (
+	// string
+	// It is just a basic string with inner whitespace preserved. No quotes
+	// should be used in the file.
+	TypeString Type = iota
+
+	// Type: image/color.RGBA
+	// Represented as a 24 bit hexadecimal number (case insensitive)
+	// preceded with a # sign where the first two digits represent the red
+	// channel, the middle two digits represent the green channel, and the
+	// last two digits represent the blue channel.
+	TypeColor
+
+	// Type: int
+	// An integer literal, like 123456789
+	TypeInteger
+
+	// Type: float64
+	// A floating point literal, like 1234.56789
+	TypeFloat
+
+	// Type: bool
+	// Values true, yes, on, and 1 are all truthy (case insensitive) and
+	// anything else is falsy.
+	TypeBoolean
+)
+
+// Config holds a list of configuration parameters.
+type Config struct {
+	// LegalParameters holds the names and types of all parameters that can
+	// be parsed. If the parser runs into a parameter that is not listed
+	// here, it will print out an error message and keep on parsing.
+	LegalParameters map[string] Type
+
+	// Parameters holds the names and values of all parsed parameters. If a
+	// value is non-nil, it can be safely type asserted into whatever type
+	// was requested.
+	Parameters map[string] any
+}
+
+// Load loads and parses the files /etc/xdg/<name>/<name>.conf and
+// <home>/.config/<name>/<name>.conf, unless the corresponding XDG environment
+// variables are set - then it uses those.
+func (config *Config) Load (name string) (err error) {
+	if nameIsIllegal(name) {
+		err = ErrorIllegalName
+		return
+	}
+
+	for _, directory := range configDirs {
+		path := filepath.Join(directory, name, name + ".conf")
+		
+		file, fileErr := os.Open(path)
+		if fileErr != nil { continue }
+		parseErr := config.LoadFrom(file)
+		defer file.Close()
+		
+		if parseErr != nil {
+			println (
+				"config: error in file", path +
+				":", parseErr.Error())
+		}
+	}
+
+	return
+}
+
+// LoadFrom parses a configuration file from an io.Reader. Configuration files
+// are divided into lines where each line may be blank, a comment, or a
+// key-value pair. If the line is blank or begins with a # character, it is
+// ignored. Else, the line must have a key and a value separated by a colon.
+// Before they are processed, leading and trailing whitespace is trimmed from
+// the key and the value. Keys are case sensitive.
+func (config *Config) LoadFrom (reader io.Reader) (err error) {
+	if config.LegalParameters == nil {
+		config.LegalParameters = make(map[string] Type)
+	}
+	
+	if config.Parameters == nil {
+		config.Parameters = make(map[string] any)
+	}
+	
+	scanner := bufio.NewScanner(reader)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		
+		if len(line) == 0 {
+			continue
+		}
+
+		if line[0] == '#' {
+			continue
+		}
+	
+		key, value, found := strings.Cut(scanner.Text(), ":")
+		if !found {
+			err = ErrorNoSeparator
+			return
+		}
+		key   = strings.TrimSpace(key)
+		value = strings.TrimSpace(value)
+
+		what, isKnown := config.LegalParameters[key]
+		if !isKnown {
+			err = ErrorUnknownParameter
+			return
+		}
+
+		switch what {
+		case TypeString:
+			config.Parameters[key] = value
+			
+		case TypeColor:
+			var valueColor color.Color
+			valueColor, err = parseColor(value)
+			if err != nil { return }
+			config.Parameters[key] = valueColor
+		
+		case TypeInteger:
+			var valueInt int
+			valueInt, err = strconv.Atoi(value)
+			if err != nil {
+				err = ErrorMalformedIntegerLiteral
+				return
+			}
+			config.Parameters[key] = valueInt
+			
+		case TypeFloat:
+			var valueFloat float64
+			valueFloat, err = strconv.ParseFloat(value, 64)
+			if err != nil {
+				err = ErrorMalformedFloatLiteral
+				return
+			}
+			config.Parameters[key] = valueFloat
+			
+		case TypeBoolean:
+			value = strings.ToLower(value)
+			truthy :=
+				value == "true" ||
+				value == "yes"  ||
+				value == "on"   ||
+				value == "1"
+			config.Parameters[key] = truthy
+		}
+	}
+
+	return
+}
+
+// Save overwrites the main user configuration file, which is located at
+// <home>/.config/<name>/<name>.conf unless $XDG_CONFIG_HOME has been set, in
+// which case the value of that variable is used instead.
+func (config *Config) Save (name string) (err error) {
+	if nameIsIllegal(name) {
+		err = ErrorIllegalName
+		return
+	}
+
+	err = os.MkdirAll(configHome, 0755)
+	if err != nil { return }
+	
+	file, err := os.OpenFile (
+		filepath.Join(configHome, name, name + ".conf"),
+		os.O_WRONLY | os.O_CREATE | os.O_TRUNC, 0744)
+	if err != nil { return }
+	defer file.Close()
+
+	err = config.SaveTo(file)
+	if err != nil { return }
+
+	return
+}
+
+// SaveTo writes the configuration data to the specified io.Writer. Keys are
+// alphabetically sorted.
+func (config *Config) SaveTo (writer io.Writer) (err error) {
+	keys := make([]string, len(config.Parameters))
+	index := 0
+	for key, _ := range config.Parameters {
+		keys[index] = key
+		index ++
+	}
+	sort.Strings(keys)
+
+	for _, key := range keys {
+		value := config.Parameters[key]
+		switch value.(type) {
+		case string:
+			fmt.Fprintf(writer,"%s: %s\n", key, value.(string))
+			
+		case color.RGBA:
+			colorValue := value.(color.RGBA)
+			colorInt := 
+				uint64(colorValue.R) << 16 |
+				uint64(colorValue.G) << 8  |
+				uint64(colorValue.B)
+			fmt.Fprintf(writer,"%s: #%06x\n", key, colorInt)
+			
+		case int:
+			fmt.Fprintf(writer,"%s: %d\n", key, value.(int))
+			
+		case float64:
+			fmt.Fprintf(writer,"%s: %f\n", key, value.(float64))
+			
+		case bool:
+			fmt.Fprintf(writer,"%s: %t\n", key, value.(bool))
+		default:
+			fmt.Fprintf(writer,"# %s: unknown type\n", key)
+		}
+	}
+
+	return
+}
+
+func parseColor (value string) (valueColor color.Color, err error) {
+	if value[0] == '#' {
+		if len(value) != 7  {
+			err = ErrorWrongColorLength
+			return
+		}
+
+		var colorInt uint64
+		colorInt, err = strconv.ParseUint(value[1:7], 16, 24)
+		if err != nil  {
+			err = ErrorMalformedColorLiteral
+			return
+		}
+
+		valueColor = color.RGBA {
+			R: uint8(colorInt >> 16),
+			G: uint8(colorInt >> 8),
+			B: uint8(colorInt),
+			A: 0xFF,
+		}
+	} else {
+		err = ErrorMalformedColorLiteral
+		return
+	}
+
+	return
+}
+
+func nameIsIllegal (name string) (legal bool) {
+	legal = strings.ContainsAny(name, "/\\|:.%")
+	return
+}

config/xdg.go

@@ -0,0 +1,54 @@
+package config
+
+import "os"
+import "strings"
+import "path/filepath"
+
+var homeDirectory string
+var configHome    string
+var configDirs    []string
+var dataHome      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)
+
+	configHome = os.Getenv("XDG_DATA_HOME")
+	if configHome == "" {
+		configHome = filepath.Join(homeDirectory, "/.local/share/")
+	}
+
+	cacheHome = os.Getenv("XDG_CACHE_HOME")
+	if cacheHome == "" {
+		configHome = filepath.Join(homeDirectory, "/.cache/")
+	}
+}
+
+// DataHome returns the path to the directory where user data should be stored.
+func DataHome (name string) (home string) {
+	home = filepath.Join(dataHome, name)
+	return
+}
+
+// CacheHome returns the path to the directory where cache files should be
+// stored.
+func CacheHome (name string) (home string) {
+	home = filepath.Join(cacheHome, name)
+	return
+}

examples/confview/confview.go

@@ -0,0 +1,106 @@
+package main
+
+import "os"
+import "image"
+import "image/color"
+import _ "image/png"
+import "git.tebibyte.media/sashakoshka/stone"
+import "git.tebibyte.media/sashakoshka/stone/config"
+import _ "git.tebibyte.media/sashakoshka/stone/backends/x"
+
+var application = &stone.Application { }
+var inputState struct {
+	x int
+	y int
+}
+var globalConfig config.Config
+
+func main () {
+	application.SetTitle("configuration viewer")
+	application.SetSize(32, 16)
+
+	iconFile16, err := os.Open("assets/scaffold16.png")
+	if err != nil { panic(err) }
+	icon16, _, err := image.Decode(iconFile16)
+	if err != nil { panic(err) }
+	iconFile16.Close()
+	iconFile32, err := os.Open("assets/scaffold32.png")
+	if err != nil { panic(err) }
+	icon32, _, err := image.Decode(iconFile32)
+	if err != nil { panic(err) }
+	iconFile16.Close()
+	
+	application.SetIcon([]image.Image { icon16, icon32 })
+	
+	application.OnPress(onPress)
+	application.OnRelease(onRelease)
+	application.OnMouseMove(onMouseMove)
+	application.OnStart(onStart)
+	application.OnResize(redraw)
+	
+	err = application.Run()
+	if err != nil { panic(err) }
+}
+
+func onStart () {
+	// this is just copy pasted from config.go
+	globalConfig = config.Config {
+		LegalParameters: map[string] config.Type {
+			"fontNormal":      config.TypeString,
+			"fontSize":        config.TypeInteger,
+			"padding":         config.TypeInteger,
+			"center":          config.TypeBoolean,
+			"colorBackground": config.TypeColor,
+			"colorForeground": config.TypeColor,
+			"colorDim":        config.TypeColor,
+			"colorRed":        config.TypeColor,
+			"colorYellow":     config.TypeColor,
+			"colorGreen":      config.TypeColor,
+			"colorBlue":       config.TypeColor,
+			"colorPurple":     config.TypeColor,
+		},
+		
+		Parameters: map[string] any {
+			"fontNormal": "",
+			"fontSize":   11,
+			"padding":    2,
+			"center":     false,
+			"colorBackground":
+				color.RGBA { R: 0, G: 0, B: 0, A: 0 },
+			"colorForeground":
+				color.RGBA { R: 0xFF, G: 0xFF, B: 0xFF, A: 0xFF },
+			"colorDim":
+				color.RGBA { R: 0x80, G: 0x80, B: 0x80, A: 0xFF },
+			"colorRed":
+				color.RGBA { R: 0xFF, G: 0x00, B: 0x00, A: 0xFF },
+			"colorYellow":
+				color.RGBA { R: 0xFF, G: 0xFF, B: 0x00, A: 0xFF },
+			"colorGreen":
+				color.RGBA { R: 0x00, G: 0xFF, B: 0x00, A: 0xFF },
+			"colorBlue":
+				color.RGBA { R: 0x00, G: 0x80, B: 0xFF, A: 0xFF },
+			"colorPurple":
+				color.RGBA { R: 0x80, G: 0x40, B: 0xFF, A: 0xFF },
+		},
+	}
+	globalConfig.Load("stone")
+	redraw()
+}
+
+func redraw () {
+	// i fucking love go interfaces
+	application.Clear()
+	application.SetDot(0, 0)
+	globalConfig.SaveTo(application)
+}
+
+func onPress (button stone.Button, modifiers stone.Modifiers) {
+}
+
+func onRelease (button stone.Button) {
+}
+
+func onMouseMove (x, y int) {
+	inputState.x = x
+	inputState.y = y
+}

examples/draw/main.go

@@ -50,7 +50,8 @@ func onRelease (button stone.Button) {
 	}
 }
 
-func onMouseMove (x, y int) {	if mousePressed {
+func onMouseMove (x, y int) {
+	if mousePressed {
 		application.SetRune(x, y, '#')
 		application.Draw()
 	}