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https://git.sr.ht/~eliasnaur/gio
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Elias Naur
ad4215a7eb
The dp and sp units are approximate and mostly used for layout dimensions that operate in whole pixels. This change alters the Config methods to return pixels in ints instead of floats, which results in smoother use for layout and emphasize the inexactness of the device independent units. Clients can still access to raw PxPrDp and PxPrSp factors from Config. Signed-off-by: Elias Naur <mail@eliasnaur.com>
52 lines
1.2 KiB
Go
52 lines
1.2 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/ui"
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"gioui.org/ui/draw"
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"gioui.org/ui/f32"
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"gioui.org/ui/layout"
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)
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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(c *ui.Config, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
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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 = c.Dp(wf*dpPrPx), c.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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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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draw.ImageOp{Img: im.Src, Rect: im.Rect}.Add(ops)
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draw.DrawOp{Rect: dr}.Add(ops)
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return layout.Dimens{Size: d, Baseline: d.Y}
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}
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