blob: f1e8b87fded3b61fcd4f8ddcc256e6275cdce604 [file] [log] [blame]
// Copyright 2014 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 linux darwin
package font
import (
"bytes"
"fmt"
"testing"
)
func looksLikeATTF(b []byte) error {
if len(b) < 256 {
return fmt.Errorf("not a TTF: not enough data")
}
b = b[:256]
// Look for the 4-byte magic header. See
// http://www.microsoft.com/typography/otspec/otff.htm
switch string(b[:4]) {
case "\x00\x01\x00\x00", "ttcf":
// No-op.
default:
return fmt.Errorf("not a TTF: missing magic header")
}
// Look for a glyf table.
if i := bytes.Index(b, []byte("glyf")); i < 0 {
return fmt.Errorf(`not a TTF: missing "glyf" table`)
} else if i%0x10 != 0x0c {
return fmt.Errorf(`not a TTF: invalid "glyf" offset 0x%02x`, i)
}
return nil
}
func TestLoadFonts(t *testing.T) {
if err := looksLikeATTF(Default()); err != nil {
t.Errorf("default font: %v", err)
}
if err := looksLikeATTF(Monospace()); err != nil {
t.Errorf("monospace font: %v", err)
}
}