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// 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.
//go: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 TestLoadDefault(t *testing.T) {
def, err := buildDefault()
if err != nil {
t.Skip("default font not found")
}
if err := looksLikeATTF(def); err != nil {
t.Errorf("default font: %v", err)
}
}
func TestLoadMonospace(t *testing.T) {
mono, err := buildMonospace()
if err != nil {
t.Skip("mono font not found")
}
if err := looksLikeATTF(mono); err != nil {
t.Errorf("monospace font: %v", err)
}
}
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