golang-image/example/font/main.go

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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build example
//
// This build tag means that "go install golang.org/x/image/..." doesn't
// install this example program. Use "go run main.go" to run it or "go install
// -tags=example" to install it.
// Font is a basic example of using fonts.
package main
import (
"flag"
"image"
"image/color"
"image/draw"
"image/png"
"io/ioutil"
"log"
"os"
"path/filepath"
"strings"
"golang.org/x/image/font"
"golang.org/x/image/font/plan9font"
"golang.org/x/image/math/fixed"
)
var (
fontFlag = flag.String("font", "",
`filename of the Plan 9 font or subfont file, such as "lucsans/unicode.8.font" or "lucsans/lsr.14"`)
firstRuneFlag = flag.Int("firstrune", 0, "the Unicode code point of the first rune in the subfont file")
)
func pt(p fixed.Point26_6) image.Point {
return image.Point{
X: int(p.X+32) >> 6,
Y: int(p.Y+32) >> 6,
}
}
func main() {
flag.Parse()
// TODO: mmap the files.
if *fontFlag == "" {
flag.Usage()
log.Fatal("no font specified")
}
var face font.Face
if strings.HasSuffix(*fontFlag, ".font") {
fontData, err := ioutil.ReadFile(*fontFlag)
if err != nil {
log.Fatal(err)
}
dir := filepath.Dir(*fontFlag)
face, err = plan9font.ParseFont(fontData, func(name string) ([]byte, error) {
return ioutil.ReadFile(filepath.Join(dir, filepath.FromSlash(name)))
})
if err != nil {
log.Fatal(err)
}
} else {
fontData, err := ioutil.ReadFile(*fontFlag)
if err != nil {
log.Fatal(err)
}
face, err = plan9font.ParseSubfont(fontData, rune(*firstRuneFlag))
if err != nil {
log.Fatal(err)
}
}
dst := image.NewRGBA(image.Rect(0, 0, 800, 300))
draw.Draw(dst, dst.Bounds(), image.Black, image.Point{}, draw.Src)
d := &font.Drawer{
Dst: dst,
Src: image.White,
Face: face,
}
ss := []string{
"The quick brown fox jumps over the lazy dog.",
"Hello, 世界.",
"U+FFFD is \ufffd.",
}
for i, s := range ss {
d.Dot = fixed.P(20, 100*i+80)
dot0 := pt(d.Dot)
d.DrawString(s)
dot1 := pt(d.Dot)
dst.SetRGBA(dot0.X, dot0.Y, color.RGBA{0xff, 0x00, 0x00, 0xff})
dst.SetRGBA(dot1.X, dot1.Y, color.RGBA{0x00, 0x00, 0xff, 0xff})
}
out, err := os.Create("out.png")
if err != nil {
log.Fatal(err)
}
defer out.Close()
if err := png.Encode(out, dst); err != nil {
log.Fatal(err)
}
}