forked from joejulian/gio
Elias Naur
3784ece6dd
Package ui is now only about units except for the Config.Now method. Remove Now and rename Config to Converter. Add layout.Config to replace the old ui.Config. Signed-off-by: Elias Naur <mail@eliasnaur.com>
55 lines
1.3 KiB
Go
55 lines
1.3 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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// Package widget implements common widgets.
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package widget
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import (
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"image"
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"gioui.org/f32"
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"gioui.org/layout"
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"gioui.org/op/paint"
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"gioui.org/unit"
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)
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// Image is a widget that displays an image.
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type Image struct {
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// Src is the image to display.
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Src image.Image
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// Rect is the source rectangle.
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Rect image.Rectangle
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// Scale is the ratio of image pixels to
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// device pixels. If zero, a scale that
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// makes the image appear at approximately
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// 72 DPI is used.
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Scale float32
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}
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func (im Image) Layout(gtx *layout.Context) {
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size := im.Src.Bounds()
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wf, hf := float32(size.Dx()), float32(size.Dy())
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var w, h int
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if im.Scale == 0 {
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const dpPrPx = 160 / 72
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w, h = gtx.Px(unit.Dp(wf*dpPrPx)), gtx.Px(unit.Dp(hf*dpPrPx))
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} else {
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w, h = int(wf*im.Scale+.5), int(hf*im.Scale+.5)
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}
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cs := gtx.Constraints
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d := image.Point{X: cs.Width.Constrain(w), Y: cs.Height.Constrain(h)}
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aspect := float32(w) / float32(h)
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dw, dh := float32(d.X), float32(d.Y)
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dAspect := dw / dh
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if aspect < dAspect {
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d.X = int(dh*aspect + 0.5)
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} else {
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d.Y = int(dw/aspect + 0.5)
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}
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dr := f32.Rectangle{
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Max: f32.Point{X: float32(d.X), Y: float32(d.Y)},
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}
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paint.ImageOp{Src: im.Src, Rect: im.Rect}.Add(gtx.Ops)
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paint.PaintOp{Rect: dr}.Add(gtx.Ops)
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gtx.Dimensions = layout.Dimensions{Size: d, Baseline: d.Y}
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}
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