Files
gio/widget/border.go
T
Elias Naur 3d37491342 all: [API] replace unit.Value with separate unit.Dp, unit.Sp types
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>
2022-05-31 10:24:09 +02:00

44 lines
774 B
Go

// SPDX-License-Identifier: Unlicense OR MIT
package widget
import (
"image"
"image/color"
"gioui.org/layout"
"gioui.org/op/clip"
"gioui.org/op/paint"
"gioui.org/unit"
)
// Border lays out a widget and draws a border inside it.
type Border struct {
Color color.NRGBA
CornerRadius unit.Dp
Width unit.Dp
}
func (b Border) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions {
dims := w(gtx)
sz := dims.Size
rr := gtx.Dp(b.CornerRadius)
width := gtx.Dp(b.Width)
sz.X -= width
sz.Y -= width
r := image.Rectangle{Max: sz}
r = r.Add(image.Point{X: width / 2, Y: width / 2})
paint.FillShape(gtx.Ops,
b.Color,
clip.Stroke{
Path: clip.UniformRRect(r, rr).Path(gtx.Ops),
Width: float32(width),
}.Op(),
)
return dims
}