mirror of
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>
111 lines
2.5 KiB
Go
111 lines
2.5 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/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) SliderStyle {
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return SliderStyle{
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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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Axis layout.Axis
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Color color.NRGBA
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Float *widget.Float
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FingerSize unit.Dp
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}
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func (s SliderStyle) Layout(gtx layout.Context) layout.Dimensions {
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const thumbRadius unit.Dp = 6
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tr := gtx.Dp(thumbRadius)
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trackWidth := gtx.Dp(2)
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axis := s.Axis
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// Keep a minimum length so that the track is always visible.
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minLength := tr + 3*tr + tr
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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.Dp(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*tr, touchSizePx)
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size := axis.Convert(image.Pt(sizeMain, sizeCross))
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o := axis.Convert(image.Pt(tr, 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*tr, sizeCross))
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dims := s.Float.Layout(gtx, axis, thumbRadius)
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gtx.Constraints.Min = gtx.Constraints.Min.Add(axis.Convert(image.Pt(0, sizeCross)))
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thumbPos := tr + int(s.Float.Value*float32(axis.Convert(dims.Size).X))
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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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rect := func(minx, miny, maxx, maxy int) image.Rectangle {
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r := image.Rect(minx, miny, maxx, maxy)
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if axis == layout.Vertical {
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r.Max.X, r.Min.X = sizeMain-r.Min.X, sizeMain-r.Max.X
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}
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r.Min = axis.Convert(r.Min)
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r.Max = axis.Convert(r.Max)
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return r
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}
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// Draw track before thumb.
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track := rect(
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tr, sizeCross/2-trackWidth/2,
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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 = rect(
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thumbPos, axis.Convert(track.Min).Y,
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sizeMain-tr, 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 := image.Pt(thumbPos, sizeCross/2)
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thumb := rect(
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pt.X-tr, pt.Y-tr,
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pt.X+tr, pt.Y+tr,
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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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