forked from joejulian/gio
Elias Naur
55 lines
1.3 KiB
Go
55 lines
1.3 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
|
|
|
|
// Package widget implements common widgets.
|
|
package widget
|
|
|
|
import (
|
|
"image"
|
|
|
|
"gioui.org/f32"
|
|
"gioui.org/layout"
|
|
"gioui.org/op/paint"
|
|
"gioui.org/ui"
|
|
)
|
|
|
|
// Image is a widget that displays an image.
|
|
type Image struct {
|
|
// Src is the image to display.
|
|
Src image.Image
|
|
// Rect is the source rectangle.
|
|
Rect image.Rectangle
|
|
// Scale is the ratio of image pixels to
|
|
// device pixels. If zero, a scale that
|
|
// makes the image appear at approximately
|
|
// 72 DPI is used.
|
|
Scale float32
|
|
}
|
|
|
|
func (im Image) Layout(gtx *layout.Context) {
|
|
size := im.Src.Bounds()
|
|
wf, hf := float32(size.Dx()), float32(size.Dy())
|
|
var w, h int
|
|
if im.Scale == 0 {
|
|
const dpPrPx = 160 / 72
|
|
w, h = gtx.Px(ui.Dp(wf*dpPrPx)), gtx.Px(ui.Dp(hf*dpPrPx))
|
|
} else {
|
|
w, h = int(wf*im.Scale+.5), int(hf*im.Scale+.5)
|
|
}
|
|
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)},
|
|
}
|
|
paint.ImageOp{Src: im.Src, Rect: im.Rect}.Add(gtx.Ops)
|
|
paint.PaintOp{Rect: dr}.Add(gtx.Ops)
|
|
gtx.Dimensions = layout.Dimensions{Size: d, Baseline: d.Y}
|
|
}
|