forked from joejulian/gio
Chris Waldon
6faed7e724
Commit 94d242d broke the widget.Image's Scale field so
that it no longer had any effect on the actual size of
the displayed image. This commit fixes that, as well as
adding tests to confirm that the widget.Image type
scales appropriately with DPI changes and its own Scale
field.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
47 lines
1.1 KiB
Go
47 lines
1.1 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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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"
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"gioui.org/op/clip"
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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 paint.ImageOp
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// Scale is the ratio of image pixels to
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// dps. If Scale is zero Image falls back to
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// a scale that match a standard 72 DPI.
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Scale float32
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}
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const defaultScale = float32(160.0 / 72.0)
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func (im Image) Layout(gtx layout.Context) layout.Dimensions {
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scale := im.Scale
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if scale == 0 {
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scale = defaultScale
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}
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size := im.Src.Size()
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wf, hf := float32(size.X), float32(size.Y)
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w, h := gtx.Px(unit.Dp(wf*scale)), gtx.Px(unit.Dp(hf*scale))
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cs := gtx.Constraints
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d := cs.Constrain(image.Pt(w, h))
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stack := op.Save(gtx.Ops)
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pixelScale := scale * gtx.Metric.PxPerDp
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op.Affine(f32.Affine2D{}.Scale(f32.Point{}, f32.Pt(pixelScale, pixelScale))).Add(gtx.Ops)
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clip.Rect(image.Rectangle{Max: d}).Add(gtx.Ops)
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im.Src.Add(gtx.Ops)
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paint.PaintOp{}.Add(gtx.Ops)
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stack.Load()
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return layout.Dimensions{Size: d}
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}
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