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https://git.sr.ht/~eliasnaur/gio
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Egon Elbre
21ef492cc9
color.RGBA has two problems with regards to using it. First the color values need to be premultiplied, whereas most APIs have non-premultiplied values. This is mainly to preserve color components with low alpha values. Second there are two ways to premultiply with sRGB. One is to premultiply after sRGB conversion, the other is before. This makes using the API more confusing. Using color.NRGBA in sRGB makes it align with CSS.e Signed-off-by: Egon Elbre <egonelbre@gmail.com>
62 lines
1.3 KiB
Go
62 lines
1.3 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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"image/color"
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"image/draw"
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"gioui.org/internal/f32color"
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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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"golang.org/x/exp/shiny/iconvg"
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)
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type Icon struct {
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Color color.NRGBA
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src []byte
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// Cached values.
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op paint.ImageOp
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imgSize int
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imgColor color.NRGBA
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}
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// NewIcon returns a new Icon from IconVG data.
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func NewIcon(data []byte) (*Icon, error) {
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_, err := iconvg.DecodeMetadata(data)
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if err != nil {
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return nil, err
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}
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return &Icon{src: data, Color: color.NRGBA{A: 0xff}}, nil
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}
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func (ic *Icon) Layout(gtx layout.Context, sz unit.Value) layout.Dimensions {
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ico := ic.image(gtx.Px(sz))
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ico.Add(gtx.Ops)
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paint.PaintOp{}.Add(gtx.Ops)
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return layout.Dimensions{
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Size: ico.Size(),
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}
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}
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func (ic *Icon) image(sz int) paint.ImageOp {
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if sz == ic.imgSize && ic.Color == ic.imgColor {
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return ic.op
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}
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m, _ := iconvg.DecodeMetadata(ic.src)
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dx, dy := m.ViewBox.AspectRatio()
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img := image.NewRGBA(image.Rectangle{Max: image.Point{X: sz, Y: int(float32(sz) * dy / dx)}})
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var ico iconvg.Rasterizer
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ico.SetDstImage(img, img.Bounds(), draw.Src)
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m.Palette[0] = f32color.NRGBAToRGBA(ic.Color)
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iconvg.Decode(&ico, ic.src, &iconvg.DecodeOptions{
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Palette: &m.Palette,
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})
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ic.op = paint.NewImageOp(img)
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ic.imgSize = sz
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ic.imgColor = ic.Color
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return ic.op
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}
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