Files
gio/widget/material/slider.go
T
Elias Naur d331dd2de8 op: rename StackOp/Push/Pop to StateOp/Save/Load
The semantics were relaxed in a previous commit; this change renames
to operations accordingly.

API change. Use gofmt to adjust your code accordingly:

gofmt -r 'op.Push(a).Pop() -> op.Save(a).Load()'
gofmt -r 'op.Push(a) -> op.Save(a)'
gofmt -r 'v.Pop() -> v.Load()'
gofmt -r 'op.StackOp -> op.StateOp'

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2021-01-12 21:28:59 +01:00

123 lines
2.7 KiB
Go

// SPDX-License-Identifier: Unlicense OR MIT
package material
import (
"image"
"image/color"
"gioui.org/f32"
"gioui.org/internal/f32color"
"gioui.org/layout"
"gioui.org/op"
"gioui.org/op/clip"
"gioui.org/op/paint"
"gioui.org/unit"
"gioui.org/widget"
)
// Slider is for selecting a value in a range.
func Slider(th *Theme, float *widget.Float, min, max float32) SliderStyle {
return SliderStyle{
Min: min,
Max: max,
Color: th.Palette.ContrastBg,
Float: float,
FingerSize: th.FingerSize,
}
}
type SliderStyle struct {
Min, Max float32
Color color.NRGBA
Float *widget.Float
FingerSize unit.Value
}
func (s SliderStyle) Layout(gtx layout.Context) layout.Dimensions {
thumbRadiusInt := gtx.Px(unit.Dp(6))
trackWidth := float32(gtx.Px(unit.Dp(2)))
thumbRadius := float32(thumbRadiusInt)
size := gtx.Constraints.Min
// Keep a minimum length so that the track is always visible.
minLength := thumbRadiusInt + 3*thumbRadiusInt + thumbRadiusInt
if size.X < minLength {
size.X = minLength
}
size.Y = 2 * thumbRadiusInt
// Try to expand to finger size, but only if the constraints
// allow for it.
touchSizePx := gtx.Px(s.FingerSize)
if touchSizePx > gtx.Constraints.Max.Y {
touchSizePx = gtx.Constraints.Max.Y
}
if size.Y < touchSizePx {
size.Y = 2 * (touchSizePx / 2)
}
st := op.Save(gtx.Ops)
op.Offset(f32.Pt(thumbRadius, 0)).Add(gtx.Ops)
gtx.Constraints.Min = image.Pt(size.X-2*thumbRadiusInt, size.Y)
s.Float.Layout(gtx, thumbRadiusInt, s.Min, s.Max)
gtx.Constraints.Min.Y = size.Y
thumbPos := thumbRadius + s.Float.Pos()
st.Load()
color := s.Color
if gtx.Queue == nil {
color = f32color.Disabled(color)
}
// Draw track before thumb.
st = op.Save(gtx.Ops)
track := f32.Rectangle{
Min: f32.Point{
X: thumbRadius,
Y: float32(size.Y/2) - trackWidth/2,
},
Max: f32.Point{
X: thumbPos,
Y: float32(size.Y/2) + trackWidth/2,
},
}
clip.RRect{Rect: track}.Add(gtx.Ops)
paint.ColorOp{Color: color}.Add(gtx.Ops)
paint.PaintOp{}.Add(gtx.Ops)
st.Load()
// Draw track after thumb.
st = op.Save(gtx.Ops)
track.Min.X = thumbPos
track.Max.X = float32(size.X) - thumbRadius
clip.RRect{Rect: track}.Add(gtx.Ops)
paint.ColorOp{Color: f32color.MulAlpha(color, 96)}.Add(gtx.Ops)
paint.PaintOp{}.Add(gtx.Ops)
st.Load()
// Draw thumb.
st = op.Save(gtx.Ops)
thumb := f32.Rectangle{
Min: f32.Point{
X: thumbPos - thumbRadius,
Y: float32(size.Y/2) - thumbRadius,
},
Max: f32.Point{
X: thumbPos + thumbRadius,
Y: float32(size.Y/2) + thumbRadius,
},
}
rr := thumbRadius
clip.RRect{
Rect: thumb,
NE: rr, NW: rr, SE: rr, SW: rr,
}.Add(gtx.Ops)
paint.ColorOp{Color: color}.Add(gtx.Ops)
paint.PaintOp{}.Add(gtx.Ops)
st.Load()
return layout.Dimensions{Size: size}
}