Files
gio-patched/widget/material/image.go
T
Elias Naur e2d0b3cfca layout: invert baseline to measure positive distance from bottom
With an inverted baseline, the zero value results in the widget
baseline aligned to its bottom.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2019-10-16 00:49:52 +02:00

51 lines
1.1 KiB
Go

// SPDX-License-Identifier: Unlicense OR MIT
package material
import (
"image"
"gioui.org/f32"
"gioui.org/layout"
"gioui.org/op/paint"
"gioui.org/unit"
)
// Image is a widget that displays an image.
type Image struct {
// Src is the image to display.
Src paint.ImageOp
// Scale is the ratio of image pixels to
// dps.
Scale float32
}
func (t *Theme) Image(img paint.ImageOp) Image {
return Image{
Src: img,
Scale: 160 / 72, // About 72 DPI.
}
}
func (im Image) Layout(gtx *layout.Context) {
size := im.Src.Size()
wf, hf := float32(size.X), float32(size.Y)
w, h := gtx.Px(unit.Dp(wf*im.Scale)), gtx.Px(unit.Dp(hf*im.Scale))
cs := gtx.Constraints
d := image.Point{X: cs.Width.Constrain(w), Y: cs.Height.Constrain(h)}
aspect := float32(w) / float32(h)
dw, dh := float32(d.X), float32(d.Y)
dAspect := dw / dh
if aspect < dAspect {
d.X = int(dh*aspect + 0.5)
} else {
d.Y = int(dw/aspect + 0.5)
}
dr := f32.Rectangle{
Max: f32.Point{X: float32(d.X), Y: float32(d.Y)},
}
im.Src.Add(gtx.Ops)
paint.PaintOp{Rect: dr}.Add(gtx.Ops)
gtx.Dimensions = layout.Dimensions{Size: d}
}