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https://git.sr.ht/~eliasnaur/gio
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Elias Naur
3d37491342
The unit.Value is a struct and thus more inconvenient to use than its
underlying float32 type. In addition, most uses don't need a general
value, but rather a specific unit given by the context. This change
replaces unit.Value with two float32 units, Dp and Sp. It also changes
variables and parameters of unit.Value to a specific unit type matching
the context. That is, unit.Dp everywhere except for text sizes which are
in Sp.
Switching to typed float32s has multiple advantages
- They can be constants:
const touchSlop = unit.Dp(16)
- Casting untyped constants is no longer necessary:
insets := layout.UniformInset(16)
- Calculation with values is natural:
func (s ScrollbarStyle) Width() unit.Dp {
return s.Indicator.MinorWidth + s.Track.MinorPadding + s.Track.MinorPadding
}
The main API change is that calls to gtx.Px must be replaced with either
gtx.Dp or gtx.Sp depending on the unit.
Idea by Christophe Meessen.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
102 lines
2.6 KiB
Go
102 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/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.Dp
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}
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func (s SliderStyle) Layout(gtx layout.Context) layout.Dimensions {
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thumbRadius := gtx.Dp(6)
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trackWidth := gtx.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.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*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 := image.Rectangle{
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Min: image.Pt(pt.X-thumbRadius, pt.Y-thumbRadius),
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Max: image.Pt(pt.X+thumbRadius, 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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