gen.go

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

     1  // Copyright 2016 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  // +build ignore
     7  
     8  package main
     9  
    10  // This program generates the subdirectories of Go packages that contain []byte
    11  // versions of the TrueType font files under ./ttfs.
    12  //
    13  // Currently, "go run gen.go" needs to be run manually. This isn't done by the
    14  // usual "go generate" mechanism as there isn't any other Go code in this
    15  // directory (excluding sub-directories) to attach a "go:generate" line to.
    16  //
    17  // In any case, code generation should only need to happen when the underlying
    18  // TTF files change, which isn't expected to happen frequently.
    19  
    20  import (
    21  	"bytes"
    22  	"fmt"
    23  	"go/format"
    24  	"io/ioutil"
    25  	"log"
    26  	"os"
    27  	"path/filepath"
    28  	"strings"
    29  )
    30  
    31  const suffix = ".ttf"
    32  
    33  func main() {
    34  	ttfs, err := os.Open("ttfs")
    35  	if err != nil {
    36  		log.Fatal(err)
    37  	}
    38  	defer ttfs.Close()
    39  
    40  	infos, err := ttfs.Readdir(-1)
    41  	if err != nil {
    42  		log.Fatal(err)
    43  	}
    44  	for _, info := range infos {
    45  		ttfName := info.Name()
    46  		if !strings.HasSuffix(ttfName, suffix) {
    47  			continue
    48  		}
    49  		do(ttfName)
    50  	}
    51  }
    52  
    53  func do(ttfName string) {
    54  	fontName := fontName(ttfName)
    55  	pkgName := pkgName(ttfName)
    56  	if err := os.Mkdir(pkgName, 0777); err != nil && !os.IsExist(err) {
    57  		log.Fatal(err)
    58  	}
    59  	src, err := ioutil.ReadFile(filepath.Join("ttfs", ttfName))
    60  	if err != nil {
    61  		log.Fatal(err)
    62  	}
    63  
    64  	desc := "a proportional-width, sans-serif"
    65  	if strings.Contains(ttfName, "Mono") {
    66  		desc = "a fixed-width, slab-serif"
    67  	}
    68  
    69  	b := new(bytes.Buffer)
    70  	fmt.Fprintf(b, "// generated by go run gen.go; DO NOT EDIT\n\n")
    71  	fmt.Fprintf(b, "// Package %s provides the %q TrueType font\n", pkgName, fontName)
    72  	fmt.Fprintf(b, "// from the Go font family. It is %s font.\n", desc)
    73  	fmt.Fprintf(b, "//\n")
    74  	fmt.Fprintf(b, "// See https://blog.golang.org/go-fonts for details.\n")
    75  	fmt.Fprintf(b, "package %s\n\n", pkgName)
    76  	fmt.Fprintf(b, "// TTF is the data for the %q TrueType font.\n", fontName)
    77  	fmt.Fprintf(b, "var TTF = []byte{")
    78  	for i, x := range src {
    79  		if i&15 == 0 {
    80  			b.WriteByte('\n')
    81  		}
    82  		fmt.Fprintf(b, "%#02x,", x)
    83  	}
    84  	fmt.Fprintf(b, "\n}\n")
    85  
    86  	dst, err := format.Source(b.Bytes())
    87  	if err != nil {
    88  		log.Fatal(err)
    89  	}
    90  	if err := ioutil.WriteFile(filepath.Join(pkgName, "data.go"), dst, 0666); err != nil {
    91  		log.Fatal(err)
    92  	}
    93  }
    94  
    95  // fontName maps "Go-Regular.ttf" to "Go Regular".
    96  func fontName(ttfName string) string {
    97  	s := ttfName[:len(ttfName)-len(suffix)]
    98  	s = strings.Replace(s, "-", " ", -1)
    99  	return s
   100  }
   101  
   102  // pkgName maps "Go-Regular.ttf" to "goregular".
   103  func pkgName(ttfName string) string {
   104  	s := ttfName[:len(ttfName)-len(suffix)]
   105  	s = strings.Replace(s, "-", "", -1)
   106  	s = strings.ToLower(s)
   107  	return s
   108  }
   109
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