mirror of
https://github.com/Luzifer/go-latestver.git
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41 lines
1 KiB
Go
41 lines
1 KiB
Go
package badge
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// Some of this code (namely the code for computing the
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// width of a string in a given font) was copied from
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// code.google.com/p/freetype-go/freetype/ which includes
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// the following copyright notice:
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// Copyright 2010 The Freetype-Go Authors. All rights reserved.
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import (
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"github.com/golang/freetype/truetype"
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"github.com/pkg/errors"
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"golang.org/x/image/math/fixed"
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)
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const (
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fontSize = 11
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)
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func calculateTextWidth(text string) (int, error) {
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binFont, _ := assets.ReadFile("DejaVuSans.ttf")
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font, err := truetype.Parse(binFont)
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if err != nil {
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return 0, errors.Wrap(err, "parsing truetype font")
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}
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scale := fontSize / float64(font.FUnitsPerEm())
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width := 0
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prev, hasPrev := truetype.Index(0), false
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for _, rune := range text {
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fUnitsPerEm := fixed.Int26_6(font.FUnitsPerEm())
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index := font.Index(rune)
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if hasPrev {
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width += int(font.Kern(fUnitsPerEm, prev, index))
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}
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width += int(font.HMetric(fUnitsPerEm, index).AdvanceWidth)
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prev, hasPrev = index, true
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}
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return int(float64(width) * scale), nil
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}
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