From b81666dccc8cb139e4ddfad37d7a8686fd452549 Mon Sep 17 00:00:00 2001 From: Steven Edwards Date: Fri, 4 Sep 2015 15:34:45 -0400 Subject: [PATCH] Move parseName to Name, rewritten to be lazy. Move nameEntryInASCII into the global scope. --- truetype/truetype.go | 219 +++++++++++++++---------------------------- 1 file changed, 75 insertions(+), 144 deletions(-) diff --git a/truetype/truetype.go b/truetype/truetype.go index 75ea2c6..68a9dcd 100644 --- a/truetype/truetype.go +++ b/truetype/truetype.go @@ -110,6 +110,40 @@ func readTable(ttf []byte, offsetLength []byte) ([]byte, error) { return ttf[offset:end], nil } +// nameEntryInASCII converts b, which may be UTF-16 encoded, into an ACSII string. +func nameEntryInASCII(b []byte, utf16 bool) string { + var buf []byte + if utf16 { // Equivalent to tt_name_ascii_from_utf16. + j := len(b) + if j&1 == 1 { + return "" + } + + for i := 0; i < j; i += 2 { + el := u16(b, i) + if el == 0 { + continue + } else if el < 32 || el > 127 { + buf = append(buf, '?') + } else { + buf = append(buf, byte(el)) + } + } + } else { // Equivalent to tt_name_ascii_from_other. + for _, el := range b { + if el == 0 { + continue + } else if el < 32 || el > 127 { + buf = append(buf, '?') + } else { + buf = append(buf, el) + } + } + } + + return string(buf) +} + const ( locaOffsetFormatUnknown int = iota locaOffsetFormatShort @@ -121,11 +155,6 @@ type cm struct { start, end, delta, offset uint32 } -// nnameInfo holds a font's name and style. -type nameInfo struct { - values [20]string -} - // A Font represents a Truetype font. type Font struct { // Tables sliced from the TTF data. The different tables are documented @@ -142,8 +171,6 @@ type Font struct { bounds fixed.Rectangle26_6 // Values from the maxp section. maxTwilightPoints, maxStorage, maxFunctionDefs, maxStackElements uint16 - // First value from head table. - nameRecord *nameInfo } func (f *Font) parseCmap() error { @@ -339,142 +366,6 @@ func (f *Font) parseMaxp() error { return nil } -func (f *Font) parseName() error { - if len(f.name) < 18 { // The name table is three uint16s + at least one Name Record. Name Records are six uint16s. - return FormatError("name table too short") - } - if u16(f.name, 0) != 0 { // The first uint16 in the name table should be set to 0, per the spec. - return FormatError(fmt.Sprintf("invalid format specifier: %d", u16(f.name, 0))) - } - - numNames := int(u16(f.name, 2)) // The number of Name Records is the second uint16 in the name table. - stringOffset := u16(f.name, 4) // And the offset marking the beginning of the character data is the third int16. - - if len(f.name) < int(stringOffset) { - return FormatError("string offset is larger than the name table") - } - - const ( // The platform IDs in the name table. - PLATFORM_UNICODE = 0 - PLATFORM_MACINTOSH = 1 - PLATFORM_MICROSOFT = 3 - ) - - const ( // Encoding IDs for the Microsoft platform. - MICROSOFT_SYMBOL_CS = 1 - MICROSOFT_UNICODE_CS = 2 - MICROSOFT_UCS_4 = 10 - ) - - // Keep track of which records contain the name and style information. - var foundUnicode, foundAppleEnglish, foundAppleRoman, foundMicrosoft, foundApple [2]int - foundMicrosoftEnglish := false - - // Name Records begin at the fourth uint16 and are six uint16s long. - // Loop through them and keep track of records of interest. - for offset, i := 6, 0; i < numNames; i, offset = i+1, offset+12 { - platformID, encodingID, languageID, nameID := u16(f.name, offset), u16(f.name, offset+2), u16(f.name, offset+4), NameID(u16(f.name, offset+6)) - - switch nameID { - case NameIDFontFamily, NameIDFontSubfamily: - if u16(f.name, offset+8) == 0 { // Offset + 8 is the location of the string length. If zero, skip it. - break - } - switch platformID { - case PLATFORM_UNICODE: - foundUnicode[nameID-1] = offset - case PLATFORM_MACINTOSH: - if languageID == 0 { // The language ID for English is zero. - foundAppleEnglish[nameID-1] = offset - } else if encodingID == 0 { // A zero encoding ID means Roman. - foundAppleRoman[nameID-1] = offset - } - case PLATFORM_MICROSOFT: - if foundMicrosoft[nameID-1] == 0 || languageID&0x3FF == 0x009 { // Prefer Microsoft fonts in English. - if encodingID == MICROSOFT_SYMBOL_CS || encodingID == MICROSOFT_UNICODE_CS || encodingID == MICROSOFT_UCS_4 { - foundMicrosoftEnglish = languageID&0x3FF == 9 - foundMicrosoft[nameID-1] = offset - } - } - } - } - } - - foundApple = foundAppleRoman - if foundAppleEnglish[0] > 0 { - foundApple = foundAppleEnglish - } - - var nameOffset, nameLength, styleOffset, styleLength uint16 - nameRecord := &nameInfo{} - // Retrieve ASCII version of the values. - switch { - case foundMicrosoft[0] > 0 && !(foundApple[0] > 0 && !foundMicrosoftEnglish): - nameOffset, styleOffset = u16(f.name, foundMicrosoft[0]+10)+stringOffset, u16(f.name, foundMicrosoft[1]+10)+stringOffset - nameLength, styleLength = u16(f.name, foundMicrosoft[0]+8), u16(f.name, foundMicrosoft[1]+8) - case foundApple[0] > 0: - nameOffset, styleOffset = u16(f.name, foundApple[0]+10)+stringOffset, u16(f.name, foundApple[1]+10)+stringOffset - nameLength, styleLength = u16(f.name, foundApple[0]+8), u16(f.name, foundApple[1]+8) - case foundUnicode[0] > 0: - nameOffset, styleOffset = u16(f.name, foundUnicode[0]+10)+stringOffset, u16(f.name, foundUnicode[1]+10)+stringOffset - nameLength, styleLength = u16(f.name, foundUnicode[0]+8), u16(f.name, foundUnicode[1]+8) - } - - nameRecord.values[NameIDFontFamily] = f.nameEntryInASCII(f.name[nameOffset:nameOffset+nameLength], true) - nameRecord.values[NameIDFontSubfamily] = f.nameEntryInASCII(f.name[styleOffset:styleOffset+styleLength], true) - - f.nameRecord = nameRecord - - return nil -} - -func (f *Font) nameEntryInASCII(b []byte, utf16 bool) string { - var buf []byte - if utf16 { // Equivalent to tt_name_ascii_from_utf16. - j := len(b) - if j&1 == 1 { - return "" - } - - for i := 0; i < j; i += 2 { - el := u16(b, i) - if el == 0 { - continue - } else if el < 32 || el > 127 { - buf = append(buf, '?') - } else { - buf = append(buf, byte(el)) - } - } - } else { // Equivalent to tt_name_ascii_from_other. - for _, el := range b { - if el == 0 { - continue - } else if el < 32 || el > 127 { - buf = append(buf, '?') - } else { - buf = append(buf, el) - } - } - } - - return string(buf) -} - -// Name returns the font's name. -func (f *Font) Name(id NameID) string { - if f.nameRecord == nil { - f.parseName() - } - - // Return empty string if caller requests something larger than we support. - if id > NameIDSampleText { - return "" - } - - return f.nameRecord.values[id] -} - // scale returns x divided by f.fUnitsPerEm, rounded to the nearest integer. func (f *Font) scale(x fixed.Int26_6) fixed.Int26_6 { if x >= 0 { @@ -520,6 +411,47 @@ func (f *Font) Index(x rune) Index { return 0 } +// Name returns the NameID value of a Font. +// Returns "" on error or not found. +func (f *Font) Name(id NameID) string { + if len(f.name) < 18 { // The name table is three uint16s + at least one Name Record. Name Records are six uint16s. + return "" + } + if u16(f.name, 0) != 0 { // The first uint16 in the name table should be set to 0, per the spec. + return "" + } + + numNames := int(u16(f.name, 2)) // The number of Name Records is the second uint16 in the name table. + stringOffset := u16(f.name, 4) // And the offset marking the beginning of the character data is the third int16. + + if len(f.name) < int(stringOffset) { + return "" + } + + valueOffset, valueLength, pid := uint16(0), uint16(0), uint16(0) + // Name Records begin at the fourth uint16 and are six uint16s long. + for offset, i := 6, 0; i < numNames; i, offset = i+1, offset+12 { + if u16(f.name, offset+8) == 0 { // Offset + 8 is the location of the string length. If zero, skip it. + break + } + + nameID := NameID(u16(f.name, offset+6)) + // Find the first matching nameID, regardless of platform. + if nameID == id { + valueOffset, valueLength, pid = u16(f.name, offset+10), u16(f.name, offset+8), u16(f.name, offset) + break + } + } + + if valueOffset == 0 { + return "" + } + + // Return the ASCII value of the encoded string. + // The string is encoded as UTF-16 on non-Apple pids; Apple is pid 1. + return nameEntryInASCII(f.name[stringOffset+valueOffset:stringOffset+valueOffset+valueLength], pid != 1) +} + // unscaledHMetric returns the unscaled horizontal metrics for the glyph with // the given index. func (f *Font) unscaledHMetric(i Index) (h HMetric) { @@ -722,7 +654,6 @@ func parse(ttf []byte, offset int) (font *Font, err error) { if err = f.parseHhea(); err != nil { return } - font = f return }