// SPDX-License-Identifier: Unlicense OR MIT
package material
import (
"image"
"image/color"
"math"
"gioui.org/f32"
"gioui.org/internal/f32color"
"gioui.org/io/pointer"
"gioui.org/layout"
"gioui.org/op/clip"
"gioui.org/op/paint"
"gioui.org/text"
"gioui.org/unit"
"gioui.org/widget"
)
type checkable struct {
Label string
Color color.NRGBA
Font text.Font
TextSize unit.Value
IconColor color.NRGBA
Size unit.Value
shaper text.Shaper
checkedStateIcon *widget.Icon
uncheckedStateIcon *widget.Icon
}
func (c *checkable) layout(gtx layout.Context, checked, hovered bool) layout.Dimensions {
var icon *widget.Icon
if checked {
icon = c.checkedStateIcon
} else {
icon = c.uncheckedStateIcon
}
min := gtx.Constraints.Min
dims := layout.Flex{Alignment: layout.Middle}.Layout(gtx,
layout.Rigid(func(gtx layout.Context) layout.Dimensions {
return layout.Stack{Alignment: layout.Center}.Layout(gtx,
layout.Stacked(func(gtx layout.Context) layout.Dimensions {
size := gtx.Px(c.Size) * 4 / 3
dims := layout.Dimensions{
Size: image.Point{X: size, Y: size},
}
if !hovered {
return dims
}
background := f32color.MulAlpha(c.IconColor, 70)
var p clip.Path
p.Begin(gtx.Ops)
addCircle(&p, float32(size)/2)
paint.FillShape(gtx.Ops, background, clip.Outline{Path: p.End()}.Op())
return dims
}),
layout.Stacked(func(gtx layout.Context) layout.Dimensions {
return layout.UniformInset(unit.Dp(2)).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
size := gtx.Px(c.Size)
icon.Color = c.IconColor
if gtx.Queue == nil {
icon.Color = f32color.Disabled(icon.Color)
}
icon.Layout(gtx, unit.Px(float32(size)))
return layout.Dimensions{
Size: image.Point{X: size, Y: size},
}
})
}),
)
}),
layout.Rigid(func(gtx layout.Context) layout.Dimensions {
gtx.Constraints.Min = min
return layout.W.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
return layout.UniformInset(unit.Dp(2)).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
paint.ColorOp{Color: c.Color}.Add(gtx.Ops)
return widget.Label{}.Layout(gtx, c.shaper, c.Font, c.TextSize, c.Label)
})
})
}),
)
pointer.Rect(image.Rectangle{Max: dims.Size}).Add(gtx.Ops)
return dims
}
// addCircle adds the outline of a circle to a path.
func addCircle(p *clip.Path, r float32) {
// https://pomax.github.io/bezierinfo/#circles_cubic.
const c = 4 * (math.Sqrt2 - 1) / 3 // 4*(sqrt(2)-1)/3
p.Move(f32.Point{X: 2 * r, Y: 2*r - r})
p.Cube(f32.Point{X: 0, Y: r * c}, f32.Point{X: -r + r*c, Y: r}, f32.Point{X: -r, Y: r})
p.Cube(f32.Point{X: -r * c, Y: 0}, f32.Point{X: -r, Y: -r + r*c}, f32.Point{X: -r, Y: -r})
p.Cube(f32.Point{X: 0, Y: -r * c}, f32.Point{X: r - r*c, Y: -r}, f32.Point{X: r, Y: -r})
p.Cube(f32.Point{X: r * c, Y: 0}, f32.Point{X: r, Y: r - r*c}, f32.Point{X: r, Y: r})
}