gen.go

Documentation: golang.org/x/image/font/basicfont

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build ignore
     6  
     7  // This program generates data.go.
     8  package main
     9  
    10  import (
    11  	"bytes"
    12  	"fmt"
    13  	"go/format"
    14  	"image"
    15  	"image/draw"
    16  	"io/ioutil"
    17  	"log"
    18  	"path"
    19  	"path/filepath"
    20  
    21  	"golang.org/x/image/font"
    22  	"golang.org/x/image/font/plan9font"
    23  	"golang.org/x/image/math/fixed"
    24  )
    25  
    26  func main() {
    27  	// nGlyphs is the number of glyphs to generate: 95 characters in the range
    28  	// [0x20, 0x7e], plus the replacement character.
    29  	const nGlyphs = 95 + 1
    30  	// The particular font (unicode.7x13.font) leaves the right-most column
    31  	// empty in its ASCII glyphs. We don't have to include that column in the
    32  	// generated glyphs, so we subtract one off the effective width.
    33  	const width, height, ascent = 7 - 1, 13, 11
    34  
    35  	readFile := func(name string) ([]byte, error) {
    36  		return ioutil.ReadFile(filepath.FromSlash(path.Join("../testdata/fixed", name)))
    37  	}
    38  	fontData, err := readFile("unicode.7x13.font")
    39  	if err != nil {
    40  		log.Fatalf("readFile: %v", err)
    41  	}
    42  	face, err := plan9font.ParseFont(fontData, readFile)
    43  	if err != nil {
    44  		log.Fatalf("plan9font.ParseFont: %v", err)
    45  	}
    46  
    47  	dst := image.NewRGBA(image.Rect(0, 0, width, nGlyphs*height))
    48  	draw.Draw(dst, dst.Bounds(), image.Black, image.Point{}, draw.Src)
    49  	d := &font.Drawer{
    50  		Dst:  dst,
    51  		Src:  image.White,
    52  		Face: face,
    53  	}
    54  	for i := 0; i < nGlyphs; i++ {
    55  		r := '\ufffd'
    56  		if i < nGlyphs-1 {
    57  			r = 0x20 + rune(i)
    58  		}
    59  		d.Dot = fixed.P(0, height*i+ascent)
    60  		d.DrawString(string(r))
    61  	}
    62  
    63  	w := bytes.NewBuffer(nil)
    64  	w.WriteString(preamble)
    65  	fmt.Fprintf(w, "// mask7x13 contains %d %d×%d glyphs in %d Pix bytes.\n", nGlyphs, width, height, nGlyphs*width*height)
    66  	fmt.Fprintf(w, "var mask7x13 = &image.Alpha{\n")
    67  	fmt.Fprintf(w, "  Stride: %d,\n", width)
    68  	fmt.Fprintf(w, "  Rect: image.Rectangle{Max: image.Point{%d, %d*%d}},\n", width, nGlyphs, height)
    69  	fmt.Fprintf(w, "  Pix: []byte{\n")
    70  	b := dst.Bounds()
    71  	for y := b.Min.Y; y < b.Max.Y; y++ {
    72  		if y%height == 0 {
    73  			if y != 0 {
    74  				w.WriteByte('\n')
    75  			}
    76  			i := y / height
    77  			if i < nGlyphs-1 {
    78  				i += 0x20
    79  				fmt.Fprintf(w, "// %#2x %q\n", i, rune(i))
    80  			} else {
    81  				fmt.Fprintf(w, "// U+FFFD REPLACEMENT CHARACTER\n")
    82  			}
    83  		}
    84  
    85  		for x := b.Min.X; x < b.Max.X; x++ {
    86  			if dst.RGBAAt(x, y).R > 0 {
    87  				w.WriteString("0xff,")
    88  			} else {
    89  				w.WriteString("0x00,")
    90  			}
    91  		}
    92  		w.WriteByte('\n')
    93  	}
    94  	w.WriteString("},\n}\n")
    95  
    96  	fmted, err := format.Source(w.Bytes())
    97  	if err != nil {
    98  		log.Fatalf("format.Source: %v", err)
    99  	}
   100  	if err := ioutil.WriteFile("data.go", fmted, 0644); err != nil {
   101  		log.Fatalf("ioutil.WriteFile: %v", err)
   102  	}
   103  }
   104  
   105  const preamble = `// generated by go generate; DO NOT EDIT.
   106  
   107  package basicfont
   108  
   109  // This data is derived from files in the font/fixed directory of the Plan 9
   110  // Port source code (https://github.com/9fans/plan9port) which were originally
   111  // based on the public domain X11 misc-fixed font files.
   112  
   113  import "image"
   114  
   115  `
   116
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