forked from joejulian/gio
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>
80 lines
1.6 KiB
Go
80 lines
1.6 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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"math"
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"time"
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"gioui.org/f32"
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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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)
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type LoaderStyle struct {
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Color color.NRGBA
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}
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func Loader(th *Theme) LoaderStyle {
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return LoaderStyle{
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Color: th.Palette.ContrastBg,
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}
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}
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func (l LoaderStyle) Layout(gtx layout.Context) layout.Dimensions {
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diam := gtx.Constraints.Min.X
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if minY := gtx.Constraints.Min.Y; minY > diam {
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diam = minY
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}
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if diam == 0 {
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diam = gtx.Dp(24)
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}
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sz := gtx.Constraints.Constrain(image.Pt(diam, diam))
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radius := sz.X / 2
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defer op.Offset(image.Pt(radius, radius)).Push(gtx.Ops).Pop()
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dt := float32((time.Duration(gtx.Now.UnixNano()) % (time.Second)).Seconds())
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startAngle := dt * math.Pi * 2
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endAngle := startAngle + math.Pi*1.5
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defer clipLoader(gtx.Ops, startAngle, endAngle, float32(radius)).Push(gtx.Ops).Pop()
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paint.ColorOp{
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Color: l.Color,
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}.Add(gtx.Ops)
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defer op.Offset(image.Pt(-radius, -radius)).Push(gtx.Ops).Pop()
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paint.PaintOp{}.Add(gtx.Ops)
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op.InvalidateOp{}.Add(gtx.Ops)
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return layout.Dimensions{
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Size: sz,
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}
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}
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func clipLoader(ops *op.Ops, startAngle, endAngle, radius float32) clip.Op {
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const thickness = .25
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var (
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width = radius * thickness
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delta = endAngle - startAngle
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vy, vx = math.Sincos(float64(startAngle))
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inner = radius * (1. - thickness*.5)
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pen = f32.Pt(float32(vx), float32(vy)).Mul(inner)
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center = f32.Pt(0, 0).Sub(pen)
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p clip.Path
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)
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p.Begin(ops)
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p.Move(pen)
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p.Arc(center, center, delta)
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return clip.Stroke{
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Path: p.End(),
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Width: width,
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}.Op()
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}
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