forked from joejulian/gio
vsariola
a8a48bb809
The order of subtraction when calculating f.pos from value was wrong, so setting a minimum value for a Float never really worked, although min = 0 worked as intended which is why this probably went unnoticed. Signed-off-by: vsariola <5684185+vsariola@users.noreply.github.com>
101 lines
2.1 KiB
Go
101 lines
2.1 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"
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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 float32
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Axis layout.Axis
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drag gesture.Drag
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pos float32 // position normalized to [0, 1]
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length float32
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changed bool
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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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// Layout updates the value according to drag events along the f's main axis.
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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) Layout(gtx layout.Context, pointerMargin int, min, max float32) layout.Dimensions {
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size := gtx.Constraints.Min
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f.length = float32(f.Axis.Convert(size).X)
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var de *pointer.Event
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for _, e := range f.drag.Events(gtx.Metric, gtx, gesture.Axis(f.Axis)) {
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if e.Type == pointer.Press || e.Type == pointer.Drag {
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de = &e
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}
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}
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value := f.Value
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if de != nil {
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xy := de.Position.X
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if f.Axis == layout.Vertical {
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xy = de.Position.Y
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}
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f.pos = xy / f.length
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value = min + (max-min)*f.pos
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} else if min != max {
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f.pos = (value - min) / (max - min)
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}
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// Unconditionally call setValue in case min, max, or value changed.
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f.setValue(value, min, max)
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if f.pos < 0 {
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f.pos = 0
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} else if f.pos > 1 {
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f.pos = 1
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}
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defer op.Save(gtx.Ops).Load()
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margin := f.Axis.Convert(image.Pt(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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pointer.Rect(rect).Add(gtx.Ops)
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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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func (f *Float) setValue(value, min, max float32) {
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if min > max {
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min, max = max, min
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}
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if value < min {
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value = min
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} else if value > max {
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value = max
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}
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if f.Value != value {
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f.Value = value
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f.changed = true
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}
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}
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// Pos reports the selected position.
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func (f *Float) Pos() float32 {
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return f.pos * f.length
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}
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// Changed reports whether the value has changed since
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// the last call to Changed.
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func (f *Float) Changed() bool {
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changed := f.changed
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f.changed = false
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return changed
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}
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