ed91dc314e
This lets us load a glyph at e.g. 12 pixels per em. Change-Id: I048b3db89af8670782953a8361afe0e6373df9b0 Reviewed-on: https://go-review.googlesource.com/37175 Reviewed-by: David Crawshaw <crawshaw@golang.org>
126 lines
3.1 KiB
Go
126 lines
3.1 KiB
Go
// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package sfnt_test
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import (
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"image"
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"image/draw"
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"log"
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"os"
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"golang.org/x/image/font/gofont/goregular"
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"golang.org/x/image/font/sfnt"
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"golang.org/x/image/math/fixed"
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"golang.org/x/image/vector"
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)
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func ExampleRasterizeGlyph() {
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const (
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ppem = 32
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width = 24
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height = 32
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originX = 0
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originY = 28
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)
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f, err := sfnt.Parse(goregular.TTF)
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if err != nil {
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log.Fatalf("Parse: %v", err)
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}
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var b sfnt.Buffer
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x, err := f.GlyphIndex(&b, 'G')
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if err != nil {
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log.Fatalf("GlyphIndex: %v", err)
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}
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if x == 0 {
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log.Fatalf("GlyphIndex: no glyph index found for the rune 'G'")
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}
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segments, err := f.LoadGlyph(&b, x, fixed.I(ppem), nil)
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r := vector.NewRasterizer(width, height)
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r.DrawOp = draw.Src
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for _, seg := range segments {
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// The divisions by 64 below is because the seg.Args values have type
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// fixed.Int26_6, a 26.6 fixed point number, and 1<<6 == 64.
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switch seg.Op {
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case sfnt.SegmentOpMoveTo:
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r.MoveTo(
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originX+float32(seg.Args[0])/64,
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originY-float32(seg.Args[1])/64,
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)
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case sfnt.SegmentOpLineTo:
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r.LineTo(
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originX+float32(seg.Args[0])/64,
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originY-float32(seg.Args[1])/64,
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)
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case sfnt.SegmentOpQuadTo:
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r.QuadTo(
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originX+float32(seg.Args[0])/64,
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originY-float32(seg.Args[1])/64,
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originX+float32(seg.Args[2])/64,
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originY-float32(seg.Args[3])/64,
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)
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case sfnt.SegmentOpCubeTo:
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r.CubeTo(
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originX+float32(seg.Args[0])/64,
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originY-float32(seg.Args[1])/64,
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originX+float32(seg.Args[2])/64,
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originY-float32(seg.Args[3])/64,
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originX+float32(seg.Args[4])/64,
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originY-float32(seg.Args[5])/64,
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)
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}
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}
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// TODO: call ClosePath? Once overall or once per contour (i.e. MoveTo)?
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dst := image.NewAlpha(image.Rect(0, 0, width, height))
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r.Draw(dst, dst.Bounds(), image.Opaque, image.Point{})
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const asciiArt = ".++8"
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buf := make([]byte, 0, height*(width+1))
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for y := 0; y < height; y++ {
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for x := 0; x < width; x++ {
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a := dst.AlphaAt(x, y).A
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buf = append(buf, asciiArt[a>>6])
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}
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buf = append(buf, '\n')
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}
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os.Stdout.Write(buf)
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// Output:
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// ........................
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// ........................
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// ........................
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// ........................
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// ..........+++++++++.....
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// .......+8888888888888+..
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// ......8888888888888888..
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// ....+8888+........++88..
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// ....8888................
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// ...8888.................
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// ..+888+.................
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// ..+888..................
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// ..888+..................
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// .+888+..................
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// .+888...................
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// .+888...................
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// .+888...................
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// .+888..........+++++++..
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// .+888..........8888888..
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// .+888+.........+++8888..
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// ..888+............+888..
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// ..8888............+888..
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// ..+888+...........+888..
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// ...8888+..........+888..
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// ...+8888+.........+888..
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// ....+88888+.......+888..
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// .....+8888888888888888..
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// .......+888888888888++..
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// ..........++++++++......
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// ........................
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// ........................
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// ........................
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}
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