forked from joejulian/gio
Thomas Bruyelle
ae8a377cda
The funcs replace stack.Push and macro.Record, which become private. This makes stack and macro faster to write, in particular for stacks where you can just write the following line to save and restore the state : defer op.Push(ops).Pop() This usage requires Push to return a pointer (since Pop has a pointer receiver), or else the code doesn't compile. For consistancy, I tried to do the same for op.Record, but this implied to turn all the MacroOp fields into pointers, and this caused some panics. As a result, op.Record doesn't return a pointer. An other side effect pointed by Larry Clapp: StackOp and MacroOp are not re-usable any more, you have to allocate a new one for each usage, using the described funcs above. Signed-off-by: Thomas Bruyelle <thomas.bruyelle@gmail.com>
107 lines
2.3 KiB
Go
107 lines
2.3 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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package widget
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import (
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"image"
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"time"
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"gioui.org/f32"
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"gioui.org/gesture"
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"gioui.org/io/key"
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"gioui.org/io/pointer"
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"gioui.org/layout"
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"gioui.org/op"
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)
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// Clickable represents a clickable area.
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type Clickable struct {
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click gesture.Click
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clicks []Click
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// prevClicks is the index into clicks that marks the clicks
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// from the most recent Layout call. prevClicks is used to keep
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// clicks bounded.
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prevClicks int
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history []Press
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}
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// Click represents a click.
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type Click struct {
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Modifiers key.Modifiers
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NumClicks int
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}
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// Press represents a past pointer press.
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type Press struct {
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Position f32.Point
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Time time.Time
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}
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// Clicked reports whether there are pending clicks as would be
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// reported by Clicks. If so, Clicked removes the earliest click.
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func (b *Clickable) Clicked() bool {
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if len(b.clicks) == 0 {
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return false
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}
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n := copy(b.clicks, b.clicks[1:])
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b.clicks = b.clicks[:n]
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if b.prevClicks > 0 {
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b.prevClicks--
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}
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return true
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}
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// Clicks returns and clear the clicks since the last call to Clicks.
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func (b *Clickable) Clicks() []Click {
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clicks := b.clicks
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b.clicks = nil
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b.prevClicks = 0
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return clicks
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}
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// History is the past pointer presses useful for drawing markers.
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// History is retained for a short duration (about a second).
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func (b *Clickable) History() []Press {
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return b.history
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}
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func (b *Clickable) Layout(gtx layout.Context) layout.Dimensions {
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b.update(gtx)
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stack := op.Push(gtx.Ops)
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pointer.Rect(image.Rectangle{Max: gtx.Constraints.Min}).Add(gtx.Ops)
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b.click.Add(gtx.Ops)
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stack.Pop()
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for len(b.history) > 0 {
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c := b.history[0]
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if gtx.Now().Sub(c.Time) < 1*time.Second {
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break
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}
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n := copy(b.history, b.history[1:])
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b.history = b.history[:n]
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}
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return layout.Dimensions{Size: gtx.Constraints.Min}
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}
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// update the button state by processing events.
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func (b *Clickable) update(gtx layout.Context) {
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// Flush clicks from before the last update.
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n := copy(b.clicks, b.clicks[b.prevClicks:])
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b.clicks = b.clicks[:n]
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b.prevClicks = n
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for _, e := range b.click.Events(gtx) {
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switch e.Type {
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case gesture.TypeClick:
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b.clicks = append(b.clicks, Click{
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Modifiers: e.Modifiers,
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NumClicks: e.NumClicks,
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})
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case gesture.TypePress:
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b.history = append(b.history, Press{
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Position: e.Position,
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Time: gtx.Now(),
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})
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}
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}
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}
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