forked from joejulian/gio
Elias Naur
a63e0cb44a
op.Offset is a convenience function most often used by layouts. Layouts usually operate in integer coordinates, and the float32 version of op.Offset needlessly force conversions from int to float32. This change makes op.Offset take integer coordinates, to better match its intended use. Signed-off-by: Elias Naur <mail@eliasnaur.com>
103 lines
2.6 KiB
Go
103 lines
2.6 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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package material
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import (
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"image"
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"image/color"
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"gioui.org/f32"
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"gioui.org/internal/f32color"
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"gioui.org/layout"
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"gioui.org/op"
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"gioui.org/op/clip"
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"gioui.org/op/paint"
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"gioui.org/unit"
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"gioui.org/widget"
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)
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// Slider is for selecting a value in a range.
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func Slider(th *Theme, float *widget.Float, min, max float32) SliderStyle {
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return SliderStyle{
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Min: min,
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Max: max,
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Color: th.Palette.ContrastBg,
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Float: float,
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FingerSize: th.FingerSize,
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}
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}
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type SliderStyle struct {
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Min, Max float32
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Color color.NRGBA
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Float *widget.Float
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FingerSize unit.Value
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}
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func (s SliderStyle) Layout(gtx layout.Context) layout.Dimensions {
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thumbRadius := gtx.Px(unit.Dp(6))
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trackWidth := gtx.Px(unit.Dp(2))
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axis := s.Float.Axis
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// Keep a minimum length so that the track is always visible.
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minLength := thumbRadius + 3*thumbRadius + thumbRadius
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// Try to expand to finger size, but only if the constraints
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// allow for it.
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touchSizePx := min(gtx.Px(s.FingerSize), axis.Convert(gtx.Constraints.Max).Y)
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sizeMain := max(axis.Convert(gtx.Constraints.Min).X, minLength)
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sizeCross := max(2*thumbRadius, touchSizePx)
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size := axis.Convert(image.Pt(sizeMain, sizeCross))
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o := axis.Convert(image.Pt(thumbRadius, 0))
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trans := op.Offset(o).Push(gtx.Ops)
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gtx.Constraints.Min = axis.Convert(image.Pt(sizeMain-2*thumbRadius, sizeCross))
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s.Float.Layout(gtx, thumbRadius, s.Min, s.Max)
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gtx.Constraints.Min = gtx.Constraints.Min.Add(axis.Convert(image.Pt(0, sizeCross)))
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thumbPos := thumbRadius + int(s.Float.Pos())
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trans.Pop()
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color := s.Color
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if gtx.Queue == nil {
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color = f32color.Disabled(color)
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}
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// Draw track before thumb.
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track := image.Rectangle{
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Min: axis.Convert(image.Pt(thumbRadius, sizeCross/2-trackWidth/2)),
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Max: axis.Convert(image.Pt(thumbPos, sizeCross/2+trackWidth/2)),
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}
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paint.FillShape(gtx.Ops, color, clip.Rect(track).Op())
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// Draw track after thumb.
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track = image.Rectangle{
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Min: axis.Convert(image.Pt(thumbPos, axis.Convert(track.Min).Y)),
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Max: axis.Convert(image.Pt(sizeMain-thumbRadius, axis.Convert(track.Max).Y)),
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}
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paint.FillShape(gtx.Ops, f32color.MulAlpha(color, 96), clip.Rect(track).Op())
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// Draw thumb.
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pt := axis.Convert(image.Pt(thumbPos, sizeCross/2))
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thumb := f32.Rectangle{
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Min: f32.Pt(float32(pt.X-thumbRadius), float32(pt.Y-thumbRadius)),
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Max: f32.Pt(float32(pt.X+thumbRadius), float32(pt.Y+thumbRadius)),
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}
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paint.FillShape(gtx.Ops, color, clip.Ellipse(thumb).Op(gtx.Ops))
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return layout.Dimensions{Size: size}
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}
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func max(a, b int) int {
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if a > b {
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return a
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}
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return b
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}
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func min(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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