53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
package render
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import (
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"bytes"
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"image"
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"image/color"
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"image/draw"
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_ "image/jpeg" // load image formats for users of the API
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_ "image/png"
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"github.com/go-text/typesetting/font"
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"github.com/go-text/typesetting/shaping"
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scale "golang.org/x/image/draw"
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_ "golang.org/x/image/tiff" // load image formats for users of the API
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)
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func (r *Renderer) drawBitmap(g shaping.Glyph, bitmap font.GlyphBitmap, img draw.Image, x, y float32) error {
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// scaled glyph rect content
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top := y - fixed266ToFloat(g.YBearing)*r.PixScale
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bottom := top - fixed266ToFloat(g.Height)*r.PixScale
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right := x + fixed266ToFloat(g.Width)*r.PixScale
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switch bitmap.Format {
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case font.BlackAndWhite:
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rec := image.Rect(0, 0, bitmap.Width, bitmap.Height)
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sub := image.NewPaletted(rec, color.Palette{color.Transparent, r.Color})
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for i := range sub.Pix {
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sub.Pix[i] = bitAt(bitmap.Data, i)
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}
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rect := image.Rect(int(x), int(top), int(right), int(bottom))
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scale.NearestNeighbor.Scale(img, rect, sub, sub.Bounds(), draw.Over, nil)
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case font.JPG, font.PNG, font.TIFF:
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pix, _, err := image.Decode(bytes.NewReader(bitmap.Data))
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if err != nil {
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return err
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}
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rect := image.Rect(int(x), int(top), int(right), int(bottom))
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scale.BiLinear.Scale(img, rect, pix, pix.Bounds(), draw.Over, nil)
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}
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if bitmap.Outline != nil {
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r.drawOutline(g, *bitmap.Outline, r.filler, r.fillerScale, x, y)
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}
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return nil
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}
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// bitAt returns the bit at the given index in the byte slice.
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func bitAt(b []byte, i int) byte {
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return (b[i/8] >> (7 - i%8)) & 1
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}
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