Files
gio-patched/widget/material/button.go
T
Elias Naur 060cff257f material: make theme constructors stand-alone functions
The multitude of widget methods on Theme is unnecessary coupling in that all
possible widgets either have to be included in package material, or be
different than 3rd party widgets:

	var th *Theme

	// Core widget, calling a method on Theme.
	th.Button(...).Layout(...)

	// 3rd party widget, calling a function taking a Theme.
	datepicker.New(th, ...).Layout(...)

Another reason for the Theme methods was to enable a poor man's
theme replacement, so that you could use the same code for
compatible themes. For example,

	mat.Button(...).Layout(...)

would not need to change if the type of mat changed, as long as
the new type had a compatible method Button.

However, that point misses the fact that the mat variable had to
be declared somewhere, naming the theme package:

	var mat *material.Theme (or, say, *cocoa.Theme)

A better and complete way to replace a theme is to use import renaming.
For example, to replace the material theme with a hypothetical Windows
theme, replace

	import theme "gioui.org/widget/material"

with

	import theme "github.com/somebody/windows

This change moves all Theme widget methods to be standalone functions,
and renames the widget style types accordingly.

For example, instead of the method

	func (t *Theme) Button(...) Button

there is now a function

	func Button(t *Theme, ...) ButtonStyle

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2020-05-03 13:03:04 +02:00

192 lines
4.7 KiB
Go

// SPDX-License-Identifier: Unlicense OR MIT
package material
import (
"image"
"image/color"
"gioui.org/f32"
"gioui.org/io/pointer"
"gioui.org/layout"
"gioui.org/op"
"gioui.org/op/clip"
"gioui.org/op/paint"
"gioui.org/text"
"gioui.org/unit"
"gioui.org/widget"
)
type ButtonStyle struct {
Text string
// Color is the text color.
Color color.RGBA
Font text.Font
TextSize unit.Value
Background color.RGBA
CornerRadius unit.Value
Inset layout.Inset
shaper text.Shaper
}
type ButtonLayoutStyle struct {
Background color.RGBA
Color color.RGBA
CornerRadius unit.Value
Inset layout.Inset
}
type IconButtonStyle struct {
Background color.RGBA
Color color.RGBA
Icon *widget.Icon
Size unit.Value
Padding unit.Value
Inset layout.Inset
}
func Button(th *Theme, txt string) ButtonStyle {
return ButtonStyle{
Text: txt,
Color: rgb(0xffffff),
CornerRadius: unit.Dp(4),
Background: th.Color.Primary,
TextSize: th.TextSize.Scale(14.0 / 16.0),
Inset: layout.Inset{
Top: unit.Dp(10), Bottom: unit.Dp(10),
Left: unit.Dp(12), Right: unit.Dp(12),
},
shaper: th.Shaper,
}
}
func ButtonLayout(th *Theme) ButtonLayoutStyle {
return ButtonLayoutStyle{
Background: th.Color.Primary,
Color: th.Color.InvText,
CornerRadius: unit.Dp(4),
Inset: layout.UniformInset(unit.Dp(12)),
}
}
func IconButton(th *Theme, icon *widget.Icon) IconButtonStyle {
return IconButtonStyle{
Background: th.Color.Primary,
Color: th.Color.InvText,
Icon: icon,
Size: unit.Dp(56),
Padding: unit.Dp(16),
}
}
func (b ButtonStyle) Layout(gtx *layout.Context, button *widget.Button) {
ButtonLayoutStyle{
Background: b.Background,
CornerRadius: b.CornerRadius,
Color: b.Color,
Inset: b.Inset,
}.Layout(gtx, button, func() {
widget.Label{Alignment: text.Middle}.Layout(gtx, b.shaper, b.Font, b.TextSize, b.Text)
})
}
func (b ButtonLayoutStyle) Layout(gtx *layout.Context, button *widget.Button, w layout.Widget) {
hmin := gtx.Constraints.Width.Min
vmin := gtx.Constraints.Height.Min
layout.Stack{Alignment: layout.Center}.Layout(gtx,
layout.Expanded(func() {
rr := float32(gtx.Px(b.CornerRadius))
clip.Rect{
Rect: f32.Rectangle{Max: f32.Point{
X: float32(gtx.Constraints.Width.Min),
Y: float32(gtx.Constraints.Height.Min),
}},
NE: rr, NW: rr, SE: rr, SW: rr,
}.Op(gtx.Ops).Add(gtx.Ops)
fill(gtx, b.Background)
for _, c := range button.History() {
drawInk(gtx, c)
}
}),
layout.Stacked(func() {
gtx.Constraints.Width.Min = hmin
gtx.Constraints.Height.Min = vmin
layout.Center.Layout(gtx, func() {
b.Inset.Layout(gtx, func() {
paint.ColorOp{Color: b.Color}.Add(gtx.Ops)
w()
})
})
pointer.Rect(image.Rectangle{Max: gtx.Dimensions.Size}).Add(gtx.Ops)
button.Layout(gtx)
}),
)
}
func (b IconButtonStyle) Layout(gtx *layout.Context, button *widget.Button) {
layout.Stack{Alignment: layout.Center}.Layout(gtx,
layout.Expanded(func() {
size := gtx.Constraints.Width.Min
sizef := float32(size)
rr := sizef * .5
clip.Rect{
Rect: f32.Rectangle{Max: f32.Point{X: sizef, Y: sizef}},
NE: rr, NW: rr, SE: rr, SW: rr,
}.Op(gtx.Ops).Add(gtx.Ops)
fill(gtx, b.Background)
for _, c := range button.History() {
drawInk(gtx, c)
}
}),
layout.Stacked(func() {
layout.UniformInset(b.Padding).Layout(gtx, func() {
size := gtx.Px(b.Size) - 2*gtx.Px(b.Padding)
if b.Icon != nil {
b.Icon.Color = b.Color
b.Icon.Layout(gtx, unit.Px(float32(size)))
}
gtx.Dimensions = layout.Dimensions{
Size: image.Point{X: size, Y: size},
}
})
pointer.Ellipse(image.Rectangle{Max: gtx.Dimensions.Size}).Add(gtx.Ops)
button.Layout(gtx)
}),
)
}
func toPointF(p image.Point) f32.Point {
return f32.Point{X: float32(p.X), Y: float32(p.Y)}
}
func drawInk(gtx *layout.Context, c widget.Click) {
d := gtx.Now().Sub(c.Time)
t := float32(d.Seconds())
const duration = 0.5
if t > duration {
return
}
t = t / duration
var stack op.StackOp
stack.Push(gtx.Ops)
size := float32(gtx.Px(unit.Dp(700))) * t
rr := size * .5
col := byte(0xaa * (1 - t*t))
ink := paint.ColorOp{Color: color.RGBA{A: col, R: col, G: col, B: col}}
ink.Add(gtx.Ops)
op.TransformOp{}.Offset(c.Position).Offset(f32.Point{
X: -rr,
Y: -rr,
}).Add(gtx.Ops)
clip.Rect{
Rect: f32.Rectangle{Max: f32.Point{
X: float32(size),
Y: float32(size),
}},
NE: rr, NW: rr, SE: rr, SW: rr,
}.Op(gtx.Ops).Add(gtx.Ops)
paint.PaintOp{Rect: f32.Rectangle{Max: f32.Point{X: float32(size), Y: float32(size)}}}.Add(gtx.Ops)
stack.Pop()
op.InvalidateOp{}.Add(gtx.Ops)
}