Rewrite parseName to be consistent with freetype2.
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Steven Edwards
parent
b96c7d6be0
commit
ae9e4ed6b9
1 changed files with 119 additions and 46 deletions
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@ -20,11 +20,8 @@ package truetype // import "github.com/golang/freetype/truetype"
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"golang.org/x/image/math/fixed"
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"golang.org/x/text/encoding/unicode"
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"golang.org/x/text/transform"
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)
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// An Index is a Font's index of a rune.
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@ -93,9 +90,9 @@ type cm struct {
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start, end, delta, offset uint32
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}
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// An nr holds a font's name, style
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type nr struct {
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fontInfo [2]string
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// nnameInfo holds a font's name and style.
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type nameInfo struct {
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name, style string
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}
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// A Font represents a Truetype font.
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@ -114,8 +111,8 @@ type Font struct {
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bounds fixed.Rectangle26_6
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// Values from the maxp section.
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maxTwilightPoints, maxStorage, maxFunctionDefs, maxStackElements uint16
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// First value from head table
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nameRecord *nr
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// First value from head table.
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nameRecord nameInfo
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}
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func (f *Font) parseCmap() error {
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@ -312,62 +309,138 @@ func (f *Font) parseMaxp() error {
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}
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func (f *Font) parseName() error {
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if len(f.name) < 18 {
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return FormatError("name data too short")
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if len(f.name) < 18 { // The name table is three uint16s + at least one Name Record. Name Records are six uint16s.
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return FormatError("name table too short")
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}
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if u16(f.name, 0) != 0 {
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if u16(f.name, 0) != 0 { // The first uint16 in the name table should be set to 0, per the spec.
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return FormatError(fmt.Sprintf("invalid format specifier: %d", u16(f.name, 0)))
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}
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numNames := int(u16(f.name, 2))
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stringOffset := u16(f.name, 4)
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font := &nr{}
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numNames := int(u16(f.name, 2)) // The number of Name Records is the second uint16 in the name table.
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stringOffset := u16(f.name, 4) // And the offset marking the beginning of the character data is the third int16.
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if len(f.name) < int(stringOffset) {
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return FormatError("string offset is larger than the name table")
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}
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const ( // The platform IDs in the name table.
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PLATFORM_UNICODE = 0
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PLATFORM_MACINTOSH = 1
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PLATFORM_MICROSOFT = 3
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)
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const ( // Encoding IDs for the Microsoft platform.
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MICROSOFT_SYMBOL_CS = 1
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MICROSOFT_UNICODE_CS = 2
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MICROSOFT_UCS_4 = 10
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)
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// Keep track of which records contain the name and style information.
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var foundUnicode, foundAppleEnglish, foundAppleRoman, foundMicrosoft, foundApple [2]int
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foundMicrosoftEnglish := false
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for offset, i := 6, 0; i < numNames; i, offset = i+1, offset+12 {
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nameID := u16(f.name, offset+6)
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platformID, encodingID, languageID, nameID := u16(f.name, offset), u16(f.name, offset+2), u16(f.name, offset+4), u16(f.name, offset+6)
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switch nameID {
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case 1, 2:
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/* Keeping these here in case they're requested later.
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platformSpecificID, languageID,platformID := u16(f.name, offset+2), u16(f.name, offset+4),u16(f.name, offset)
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*/
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length, nameOffset := u16(f.name, offset+8), u16(f.name, offset+10)
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// Assume a non-UTF-16 value
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value := f.name[stringOffset+nameOffset : stringOffset+nameOffset+length]
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// but just in case... if the first byte is 0, as in luxi's 13th nameRecord,
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// assume UTF-16, try to parse it if its length is even
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if value[0] == 0 && length&1 == 0 {
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var err error
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enc := unicode.UTF16(unicode.BigEndian, unicode.IgnoreBOM)
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value, err = ioutil.ReadAll(transform.NewReader(bytes.NewReader(value), enc.NewDecoder()))
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if err != nil {
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return err
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if u16(f.name, offset+8) == 0 { // Offset + 8 is the location of the string length. If zero, skip it.
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break
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}
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switch platformID {
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case PLATFORM_UNICODE:
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foundUnicode[nameID-1] = offset
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case PLATFORM_MACINTOSH:
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if languageID == 0 { // The language ID for English is zero.
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foundAppleEnglish[nameID-1] = offset
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} else if encodingID == 0 { // A zero encoding ID means Roman.
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foundAppleRoman[nameID-1] = offset
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}
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case PLATFORM_MICROSOFT:
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if foundMicrosoft[nameID-1] == 0 || (languageID&0x3FF) == 0x009 { // Prefer Microsoft fonts in English.
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if encodingID == MICROSOFT_SYMBOL_CS || encodingID == MICROSOFT_UNICODE_CS || encodingID == MICROSOFT_UCS_4 {
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foundMicrosoftEnglish = (languageID & 0x3FF) == 9
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foundMicrosoft[nameID-1] = offset
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}
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}
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}
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// TODO: find a fail-safe method for determine if a byte slice or string is
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// UTF-16 or not.
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font.fontInfo[nameID-1] = string(value)
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}
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if font.fontInfo[0] != "" && font.fontInfo[1] != "" {
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f.nameRecord = font
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return nil
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}
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}
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foundApple = foundAppleRoman
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if foundAppleEnglish[0] > 0 {
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foundApple = foundAppleEnglish
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}
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nameRecord := nameInfo{}
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// Should we decode UTF-16 strings?
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switch {
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case foundMicrosoft[0] > 0 && !(foundApple[0] > 0 && !foundMicrosoftEnglish):
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nameOffset, styleOffset := u16(f.name, foundMicrosoft[0]+10)+stringOffset, u16(f.name, foundMicrosoft[1]+10)+stringOffset
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nameLength, styleLength := u16(f.name, foundMicrosoft[0]+8), u16(f.name, foundMicrosoft[1]+8)
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nameRecord.name = f.nameEntryInASCII(f.name[nameOffset:nameOffset+nameLength], true)
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nameRecord.style = f.nameEntryInASCII(f.name[styleOffset:styleOffset+styleLength], true)
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case foundApple[0] > 0:
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nameOffset, styleOffset := u16(f.name, foundApple[0]+10)+stringOffset, u16(f.name, foundApple[1]+10)+stringOffset
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nameLength, styleLength := u16(f.name, foundApple[0]+8), u16(f.name, foundApple[1]+8)
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nameRecord.name = f.nameEntryInASCII(f.name[nameOffset:nameOffset+nameLength], false)
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nameRecord.style = f.nameEntryInASCII(f.name[styleOffset:styleOffset+styleLength], false)
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case foundUnicode[0] > 0:
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nameOffset, styleOffset := u16(f.name, foundUnicode[0]+10)+stringOffset, u16(f.name, foundUnicode[1]+10)+stringOffset
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nameLength, styleLength := u16(f.name, foundUnicode[0]+8), u16(f.name, foundUnicode[1]+8)
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nameRecord.name = f.nameEntryInASCII(f.name[nameOffset:nameOffset+nameLength], true)
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nameRecord.style = f.nameEntryInASCII(f.name[styleOffset:styleOffset+styleLength], true)
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}
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f.nameRecord = nameRecord
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return nil
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}
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// Name returns the TrueType font's name
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func (f *Font) Name() string {
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return f.nameRecord.fontInfo[0]
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func (f *Font) nameEntryInASCII(b []byte, utf16 bool) string {
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buf := &bytes.Buffer{}
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if utf16 { // Equivalent to tt_name_ascii_from_utf16.
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j := len(b)
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if j&1 == 1 {
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return ""
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}
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for i := 0; i < j; i += 2 {
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el := u16(b, i)
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if el == 0 {
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continue
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} else if el < 32 || el > 127 {
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buf.WriteByte('?')
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} else {
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buf.WriteByte(byte(el))
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}
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}
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} else { // Equivalent to tt_name_ascii_from_other.
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for _, el := range b {
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if el == 0 {
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continue
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} else if el < 32 || el > 127 {
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buf.WriteByte('?')
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} else {
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buf.WriteByte(el)
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}
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}
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}
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return buf.String()
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}
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// Style returns the TrueType font's style
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// Name returns the font's name.
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func (f *Font) Name() string {
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return f.nameRecord.name
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}
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// Style returns the font's style.
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func (f *Font) Style() string {
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return f.nameRecord.fontInfo[1]
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return f.nameRecord.style
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}
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// scale returns x divided by f.fUnitsPerEm, rounded to the nearest integer.
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