Files
gio-patched/ui/widget/image.go
T
Elias Naur 84fb7279eb ui/draw: rename ImageOp.Img to Src
To match widget.Image.Src field name.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2019-07-18 15:58:11 +02:00

52 lines
1.2 KiB
Go

// SPDX-License-Identifier: Unlicense OR MIT
package widget
import (
"image"
"gioui.org/ui"
"gioui.org/ui/draw"
"gioui.org/ui/f32"
"gioui.org/ui/layout"
)
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(c ui.Config, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
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 = c.Px(ui.Dp(wf*dpPrPx)), c.Px(ui.Dp(hf*dpPrPx))
} else {
w, h = int(wf*im.Scale+.5), int(hf*im.Scale+.5)
}
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)},
}
draw.ImageOp{Src: im.Src, Rect: im.Rect}.Add(ops)
draw.DrawOp{Rect: dr}.Add(ops)
return layout.Dimens{Size: d, Baseline: d.Y}
}