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https://git.sr.ht/~eliasnaur/gio
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Elias Naur
d42dae73f0
This change allows users of Float to determine its state before Layout by calling Update. While here, remove the value transformation represented by the min, max, invert parameters; they're too many arguments for a computation that may as well be done by the user. Remove Float.Pos; it is better to compute its value from the dimensions returned by Float.Layout. Signed-off-by: Elias Naur <mail@eliasnaur.com>
68 lines
1.6 KiB
Go
68 lines
1.6 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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"gioui.org/gesture"
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"gioui.org/io/pointer"
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"gioui.org/layout"
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"gioui.org/op/clip"
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"gioui.org/unit"
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)
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// Float is for selecting a value in a range.
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type Float struct {
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// Value is the value of the Float, in the [0; 1] range.
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Value float32
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drag gesture.Drag
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axis layout.Axis
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length float32
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}
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// Dragging returns whether the value is being interacted with.
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func (f *Float) Dragging() bool { return f.drag.Dragging() }
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func (f *Float) Layout(gtx layout.Context, axis layout.Axis, pointerMargin unit.Dp) layout.Dimensions {
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f.Update(gtx)
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size := gtx.Constraints.Min
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f.length = float32(axis.Convert(size).X)
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f.axis = axis
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margin := axis.Convert(image.Pt(gtx.Dp(pointerMargin), 0))
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rect := image.Rectangle{
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Min: margin.Mul(-1),
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Max: size.Add(margin),
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}
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defer clip.Rect(rect).Push(gtx.Ops).Pop()
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f.drag.Add(gtx.Ops)
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return layout.Dimensions{Size: size}
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}
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// Update the Value according to drag events along the f's main axis.
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// The return value reports whether the value was changed.
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//
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// The range of f is set by the minimum constraints main axis value.
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func (f *Float) Update(gtx layout.Context) bool {
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changed := false
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for _, e := range f.drag.Events(gtx.Metric, gtx, gesture.Axis(f.axis)) {
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if f.length > 0 && (e.Kind == pointer.Press || e.Kind == pointer.Drag) {
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pos := e.Position.X
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if f.axis == layout.Vertical {
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pos = f.length - e.Position.Y
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}
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f.Value = pos / f.length
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if f.Value < 0 {
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f.Value = 0
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} else if f.Value > 1 {
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f.Value = 1
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}
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changed = true
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}
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}
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return changed
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}
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