diff options
Diffstat (limited to 'Godeps/_workspace/src/github.com/golang/freetype/truetype/truetype.go')
| -rw-r--r-- | Godeps/_workspace/src/github.com/golang/freetype/truetype/truetype.go | 165 |
1 files changed, 127 insertions, 38 deletions
diff --git a/Godeps/_workspace/src/github.com/golang/freetype/truetype/truetype.go b/Godeps/_workspace/src/github.com/golang/freetype/truetype/truetype.go index 7d166ca77..692e01526 100644 --- a/Godeps/_workspace/src/github.com/golang/freetype/truetype/truetype.go +++ b/Godeps/_workspace/src/github.com/golang/freetype/truetype/truetype.go @@ -26,6 +26,43 @@ import ( // An Index is a Font's index of a rune. type Index uint16 +// A NameID identifies a name table entry. +// +// See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6name.html +type NameID uint16 + +const ( + NameIDCopyright NameID = 0 + NameIDFontFamily = 1 + NameIDFontSubfamily = 2 + NameIDUniqueSubfamilyID = 3 + NameIDFontFullName = 4 + NameIDNameTableVersion = 5 + NameIDPostscriptName = 6 + NameIDTrademarkNotice = 7 + NameIDManufacturerName = 8 + NameIDDesignerName = 9 + NameIDFontDescription = 10 + NameIDFontVendorURL = 11 + NameIDFontDesignerURL = 12 + NameIDFontLicense = 13 + NameIDFontLicenseURL = 14 + NameIDPreferredFamily = 16 + NameIDPreferredSubfamily = 17 + NameIDCompatibleName = 18 + NameIDSampleText = 19 +) + +const ( + // A 32-bit encoding consists of a most-significant 16-bit Platform ID and a + // least-significant 16-bit Platform Specific ID. The magic numbers are + // specified at https://www.microsoft.com/typography/otspec/name.htm + unicodeEncoding = 0x00000003 // PID = 0 (Unicode), PSID = 3 (Unicode 2.0) + microsoftSymbolEncoding = 0x00030000 // PID = 3 (Microsoft), PSID = 0 (Symbol) + microsoftUCS2Encoding = 0x00030001 // PID = 3 (Microsoft), PSID = 1 (UCS-2) + microsoftUCS4Encoding = 0x0003000a // PID = 3 (Microsoft), PSID = 10 (UCS-4) +) + // An HMetric holds the horizontal metrics of a single glyph. type HMetric struct { AdvanceWidth, LeftSideBearing fixed.Int26_6 @@ -78,6 +115,51 @@ func readTable(ttf []byte, offsetLength []byte) ([]byte, error) { return ttf[offset:end], nil } +// parseSubtables returns the offset and platformID of the best subtable in +// table, where best favors a Unicode cmap encoding, and failing that, a +// Microsoft cmap encoding. offset is the offset of the first subtable in +// table, and size is the size of each subtable. +// +// If pred is non-nil, then only subtables that satisfy that predicate will be +// considered. +func parseSubtables(table []byte, name string, offset, size int, pred func([]byte) bool) ( + bestOffset int, bestPID uint32, retErr error) { + + if len(table) < 4 { + return 0, 0, FormatError(name + " too short") + } + nSubtables := int(u16(table, 2)) + if len(table) < size*nSubtables+offset { + return 0, 0, FormatError(name + " too short") + } + ok := false + for i := 0; i < nSubtables; i, offset = i+1, offset+size { + if pred != nil && !pred(table[offset:]) { + continue + } + // We read the 16-bit Platform ID and 16-bit Platform Specific ID as a single uint32. + // All values are big-endian. + pidPsid := u32(table, offset) + // We prefer the Unicode cmap encoding. Failing to find that, we fall + // back onto the Microsoft cmap encoding. + if pidPsid == unicodeEncoding { + bestOffset, bestPID, ok = offset, pidPsid>>16, true + break + + } else if pidPsid == microsoftSymbolEncoding || + pidPsid == microsoftUCS2Encoding || + pidPsid == microsoftUCS4Encoding { + + bestOffset, bestPID, ok = offset, pidPsid>>16, true + // We don't break out of the for loop, so that Unicode can override Microsoft. + } + } + if !ok { + return 0, 0, UnsupportedError(name + " encoding") + } + return bestOffset, bestPID, nil +} + const ( locaOffsetFormatUnknown int = iota locaOffsetFormatShort @@ -93,7 +175,7 @@ type cm struct { type Font struct { // Tables sliced from the TTF data. The different tables are documented // at http://developer.apple.com/fonts/TTRefMan/RM06/Chap6.html - cmap, cvt, fpgm, glyf, hdmx, head, hhea, hmtx, kern, loca, maxp, os2, prep, vmtx []byte + cmap, cvt, fpgm, glyf, hdmx, head, hhea, hmtx, kern, loca, maxp, name, os2, prep, vmtx []byte cmapIndexes []byte @@ -112,46 +194,13 @@ func (f *Font) parseCmap() error { cmapFormat4 = 4 cmapFormat12 = 12 languageIndependent = 0 - - // A 32-bit encoding consists of a most-significant 16-bit Platform ID and a - // least-significant 16-bit Platform Specific ID. The magic numbers are - // specified at https://www.microsoft.com/typography/otspec/name.htm - unicodeEncoding = 0x00000003 // PID = 0 (Unicode), PSID = 3 (Unicode 2.0) - microsoftSymbolEncoding = 0x00030000 // PID = 3 (Microsoft), PSID = 0 (Symbol) - microsoftUCS2Encoding = 0x00030001 // PID = 3 (Microsoft), PSID = 1 (UCS-2) - microsoftUCS4Encoding = 0x0003000a // PID = 3 (Microsoft), PSID = 10 (UCS-4) ) - if len(f.cmap) < 4 { - return FormatError("cmap too short") - } - nsubtab := int(u16(f.cmap, 2)) - if len(f.cmap) < 8*nsubtab+4 { - return FormatError("cmap too short") - } - offset, found, x := 0, false, 4 - for i := 0; i < nsubtab; i++ { - // We read the 16-bit Platform ID and 16-bit Platform Specific ID as a single uint32. - // All values are big-endian. - pidPsid, o := u32(f.cmap, x), u32(f.cmap, x+4) - x += 8 - // We prefer the Unicode cmap encoding. Failing to find that, we fall - // back onto the Microsoft cmap encoding. - if pidPsid == unicodeEncoding { - offset, found = int(o), true - break - - } else if pidPsid == microsoftSymbolEncoding || - pidPsid == microsoftUCS2Encoding || - pidPsid == microsoftUCS4Encoding { - - offset, found = int(o), true - // We don't break out of the for loop, so that Unicode can override Microsoft. - } - } - if !found { - return UnsupportedError("cmap encoding") + offset, _, err := parseSubtables(f.cmap, "cmap", 4, 8, nil) + if err != nil { + return err } + offset = int(u32(f.cmap, offset+4)) if offset <= 0 || offset > len(f.cmap) { return FormatError("bad cmap offset") } @@ -345,6 +394,44 @@ func (f *Font) Index(x rune) Index { return 0 } +// Name returns the Font's name value for the given NameID. It returns "" if +// there was an error, or if that name was not found. +func (f *Font) Name(id NameID) string { + x, platformID, err := parseSubtables(f.name, "name", 6, 12, func(b []byte) bool { + return NameID(u16(b, 6)) == id + }) + if err != nil { + return "" + } + offset, length := u16(f.name, 4)+u16(f.name, x+10), u16(f.name, x+8) + // Return the ASCII value of the encoded string. + // The string is encoded as UTF-16 on non-Apple platformIDs; Apple is platformID 1. + src := f.name[offset : offset+length] + var dst []byte + if platformID != 1 { // UTF-16. + if len(src)&1 != 0 { + return "" + } + dst = make([]byte, len(src)/2) + for i := range dst { + dst[i] = printable(u16(src, 2*i)) + } + } else { // ASCII. + dst = make([]byte, len(src)) + for i, c := range src { + dst[i] = printable(uint16(c)) + } + } + return string(dst) +} + +func printable(r uint16) byte { + if 0x20 <= r && r < 0x7f { + return byte(r) + } + return '?' +} + // unscaledHMetric returns the unscaled horizontal metrics for the glyph with // the given index. func (f *Font) unscaledHMetric(i Index) (h HMetric) { @@ -518,6 +605,8 @@ func parse(ttf []byte, offset int) (font *Font, err error) { f.loca, err = readTable(ttf, ttf[x+8:x+16]) case "maxp": f.maxp, err = readTable(ttf, ttf[x+8:x+16]) + case "name": + f.name, err = readTable(ttf, ttf[x+8:x+16]) case "OS/2": f.os2, err = readTable(ttf, ttf[x+8:x+16]) case "prep": |