The beginnings of a layout system

This commit is contained in:
Sasha Koshka 2023-01-10 16:39:37 -05:00
parent b1fd021120
commit 6eed70e79e
4 changed files with 244 additions and 123 deletions

136
elements/basic/container.go Normal file
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@ -0,0 +1,136 @@
package basic
import "git.tebibyte.media/sashakoshka/tomo"
import "git.tebibyte.media/sashakoshka/tomo/theme"
import "git.tebibyte.media/sashakoshka/tomo/artist"
import "git.tebibyte.media/sashakoshka/tomo/elements/core"
type Container struct {
*core.Core
core core.CoreControl
layout tomo.Layout
children []tomo.LayoutEntry
selectable bool
}
func NewContainer (layout tomo.Layout) (element *Container) {
element = &Container { }
element.Core, element.core = core.NewCore(element)
element.SetLayout(layout)
return
}
func (element *Container) SetLayout (layout tomo.Layout) {
element.layout = layout
element.recalculate()
}
func (element *Container) Adopt (child tomo.Element, expand bool) {
child.SetParentHooks (tomo.ParentHooks {
MinimumSizeChange:
func (int, int) { element.updateMinimumSize() },
SelectabilityChange:
func (bool) { element.updateSelectable() },
})
element.children = append (element.children, tomo.LayoutEntry {
Element: child,
})
element.updateMinimumSize()
element.updateSelectable()
element.recalculate()
if element.core.HasImage() { element.draw() }
}
// Disown removes the given child from the container if it is contained within
// it.
func (element *Container) Disown (child tomo.Element) {
for index, entry := range element.children {
if entry.Element == child {
entry.SetParentHooks(tomo.ParentHooks { })
element.children = append (
element.children[:index],
element.children[index + 1:]...)
break
}
}
element.updateMinimumSize()
element.updateSelectable()
element.recalculate()
if element.core.HasImage() { element.draw() }
}
// Children returns a slice containing this element's children.
func (element *Container) Children () (children []tomo.Element) {
children = make([]tomo.Element, len(element.children))
for index, entry := range element.children {
children[index] = entry.Element
}
return
}
// CountChildren returns the amount of children contained within this element.
func (element *Container) CountChildren () (count int) {
return len(element.children)
}
// Child returns the child at the specified index. If the index is out of
// bounds, this method will return nil.
func (element *Container) Child (index int) (child tomo.Element) {
if index < 0 || index > len(element.children) { return }
return element.children[index].Element
}
func (element *Container) Handle (event tomo.Event) {
switch event.(type) {
case tomo.EventResize:
resizeEvent := event.(tomo.EventResize)
element.core.AllocateCanvas (
resizeEvent.Width,
resizeEvent.Height)
element.recalculate()
element.draw()
// TODO:
}
return
}
func (element *Container) AdvanceSelection (direction int) (ok bool) {
// TODO:
return
}
func (element *Container) updateSelectable () {
selectable := false
for _, entry := range element.children {
if entry.Selectable() { selectable = true }
}
element.core.SetSelectable(selectable)
}
func (element *Container) updateMinimumSize () {
element.core.SetMinimumSize(element.layout.MinimumSize(element.children))
}
func (element *Container) recalculate () {
bounds := element.Bounds()
element.layout.Arrange(element.children, bounds.Dx(), bounds.Dy())
}
func (element *Container) draw () {
bounds := element.core.Bounds()
artist.Rectangle (
element.core,
theme.BackgroundImage(),
nil, 0,
bounds)
// TODO
for _, entry := range element.children {
artist.Paste(element.core, entry, entry.Position)
}
}

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@ -1,136 +1,90 @@
package layouts
import "image"
import "git.tebibyte.media/sashakoshka/tomo"
import "git.tebibyte.media/sashakoshka/tomo/theme"
// import "git.tebibyte.media/sashakoshka/tomo/artist"
import "git.tebibyte.media/sashakoshka/tomo/elements/core"
type verticalEntry struct {
y int
minHeight int
element tomo.Element
}
// Vertical lays its children out vertically. It can contain any number of
// children. When an child is added to the layout, it can either be set to
// contract to its minimum height or expand to fill the remaining space (space
// that is not taken up by other children or padding is divided equally among
// these). Child elements will all have the same width.
// Vertical arranges elements vertically. Elements at the start of the entry
// list will be positioned at the top, and elements at the end of the entry list
// will positioned at the bottom. All elements have the same width.
type Vertical struct {
*core.Core
core core.CoreControl
// If Gap is true, a gap will be placed between each element.
Gap bool
gap, pad bool
children []verticalEntry
selectable bool
// If Pad is true, there will be padding running along the inside of the
// layout's border.
Pad bool
}
// NewVertical creates a new vertical layout. If gap is set to true, a gap will
// be placed between each child element. If pad is set to true, padding will be
// be placed around the inside of this element's border. Usually, you will want
// these to be true.
func NewVertical (gap, pad bool) (element *Vertical) {
element = &Vertical { }
element.Core, element.core = core.NewCore(element)
element.gap = gap
element.pad = pad
element.recalculate()
return
}
// Arrange arranges a list of entries vertically.
func (layout Vertical) Arrange (entries []tomo.LayoutEntry, width, height int) {
if layout.Pad {
width -= theme.Padding() * 2
height -= theme.Padding() * 2
}
freeSpace := height
expandingElements := 0
// SetPad sets whether or not padding will be placed around the inside of this
// element's border.
func (element *Vertical) SetPad (pad bool) {
changed := element.pad != pad
element.pad = pad
if changed { element.recalculate() }
}
// SetGap sets whether or not a gap will be placed in between child elements.
func (element *Vertical) SetGap (gap bool) {
changed := element.gap != gap
element.gap = gap
if changed { element.recalculate() }
}
// Adopt adds a child element to the vertical layout. If expand is set to true,
// the element will be expanded to fill a portion of the remaining space in the
// layout.
func (element *Vertical) Adopt (child tomo.Element, expand bool) {
_, minHeight := child.MinimumSize()
child.SetParentHooks (tomo.ParentHooks {
// TODO
})
element.children = append (element.children, verticalEntry {
element: child,
minHeight: minHeight,
})
if child.Selectable() { element.core.SetSelectable(true) }
element.recalculate()
}
// Disown removes the given child from the layout if it is contained within it.
func (element *Vertical) Disown (child tomo.Element) {
for index, entry := range element.children {
if entry.element == child {
entry.element.SetParentHooks(tomo.ParentHooks { })
element.children = append (
element.children[:index],
element.children[index + 1:]...)
break
// count the number of expanding elements and the amount of free space
// for them to collectively occupy
for _, entry := range entries {
if entry.Expand {
expandingElements ++
} else {
_, entryMinHeight := entry.MinimumSize()
freeSpace -= entryMinHeight
}
}
selectable := false
for _, entry := range element.children {
if entry.element.Selectable() { selectable = true }
expandingElementHeight := 0
if expandingElements > 0 {
expandingElementHeight = freeSpace / expandingElements
}
element.core.SetSelectable(selectable)
}
// Children returns a slice containing this element's children.
func (element *Vertical) Children () (children []tomo.Element) {
children = make([]tomo.Element, len(element.children))
for index, entry := range element.children {
children[index] = entry.element
}
return
}
// CountChildren returns the amount of children contained within this element.
func (element *Vertical) CountChildren () (count int) {
return len(element.children)
}
// Child returns the child at the specified index. If the index is out of
// bounds, this method will return nil.
func (element *Vertical) Child (index int) (child tomo.Element) {
if index < 0 || index > len(element.children) { return }
return element.children[index].element
}
func (element *Vertical) Handle (event tomo.Event) {
switch event.(type) {
case tomo.EventResize:
element.recalculate()
// TODO:
// TODO:
}
return
}
func (element *Vertical) AdvanceSelection (direction int) (ok bool) {
// TODO:
return
}
func (element *Vertical) recalculate () {
var x, y int
if element.pad {
x, y := 0, 0
if layout.Pad {
x += theme.Padding()
y += theme.Padding()
}
// TODO
// set the size and position of each element
for index, entry := range entries {
if index > 0 && layout.Gap { y += theme.Padding() }
entries[index].Position = image.Pt(x, y)
entryHeight := 0
if entry.Expand {
entryHeight = expandingElementHeight
} else {
_, entryHeight = entry.MinimumSize()
}
y += entryHeight
entryBounds := entry.Bounds()
if entryBounds.Dx() != width || entryBounds.Dy() != entryHeight {
entry.Handle (tomo.EventResize {
Width: width,
Height: entryHeight,
})
}
}
}
// MinimumSize returns the minimum width and height will be needed to arrange
// the given list of entries.
func (layout Vertical) MinimumSize (entries []tomo.LayoutEntry) (width, height int) {
for index, entry := range entries {
entryWidth, entryHeight := entry.MinimumSize()
if entryWidth > width {
width = entryWidth
}
height += entryHeight
if layout.Gap && index > 0 {
height += theme.Padding()
}
}
if layout.Pad {
width += theme.Padding() * 2
height += theme.Padding() * 2
}
return
}

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@ -13,12 +13,21 @@ func run () {
window, _ := tomo.NewWindow(2, 2)
window.SetTitle("vertical stack")
layout := layouts.NewVertical(true, true)
window.Adopt(layout)
container := basic.NewContainer(layouts.Vertical { true, true })
window.Adopt(container)
layout.Adopt(basic.NewLabel("it is a label hehe"))
layout.Adopt(basic.NewButton("yeah"), false)
layout.Adopt(button := basic.NewButton("wow"), false)
label := basic.NewLabel("it is a label hehe")
button := basic.NewButton("press me")
button.OnClick (func () {
label.SetText (
"woah, this button changes the label text! since the " +
"size of this text box has changed, the window " +
"should expand (unless you resized it already).")
})
container.Adopt(label, true)
container.Adopt(basic.NewButton("yeah"), false)
container.Adopt(button, false)
window.OnClose(tomo.Stop)
window.Show()

22
tomo.go
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@ -150,6 +150,28 @@ type Window interface {
OnClose (func ())
}
// LayoutEntry associates an element with layout and positioning information so
// it can be arranged by a Layout.
type LayoutEntry struct {
Element
Position image.Point
Expand bool
}
// Layout is capable of arranging elements within a container. It is also able
// to determine the minimum amount of room it needs to do so.
type Layout interface {
// Arrange takes in a slice of entries and a bounding width and height,
// and changes the position of the entiries in the slice so that they
// are properly laid out. The given width and height should not be less
// than what is returned by MinimumSize.
Arrange (entries []LayoutEntry, width, height int)
// MinimumSize returns the minimum width and height that the layout
// needs to properly arrange the given slice of layout entries.
MinimumSize (entries []LayoutEntry) (width, height int)
}
var backend Backend
// Run initializes a backend, calls the callback function, and begins the event