font/sfnt: implement Font.GlyphName.
This is based on the post table in the sfnt file.
Change-Id: I11f7a9bd9024cfc8f92adc5abb4d5356521f0df7
Reviewed-on: https://go-review.googlesource.com/36972
Reviewed-by: David Crawshaw <crawshaw@golang.org>
diff --git a/font/sfnt/data.go b/font/sfnt/data.go
new file mode 100644
index 0000000..ad0c139
--- /dev/null
+++ b/font/sfnt/data.go
@@ -0,0 +1,68 @@
+// generated by go run gen.go; DO NOT EDIT
+
+package sfnt
+
+const numBuiltInPostNames = 258
+
+const builtInPostNamesData = "" +
+ ".notdef.nullnonmarkingreturnspaceexclamquotedblnumbersigndollarp" +
+ "ercentampersandquotesingleparenleftparenrightasteriskpluscommahy" +
+ "phenperiodslashzeroonetwothreefourfivesixseveneightninecolonsemi" +
+ "colonlessequalgreaterquestionatABCDEFGHIJKLMNOPQRSTUVWXYZbracket" +
+ "leftbackslashbracketrightasciicircumunderscoregraveabcdefghijklm" +
+ "nopqrstuvwxyzbraceleftbarbracerightasciitildeAdieresisAringCcedi" +
+ "llaEacuteNtildeOdieresisUdieresisaacuteagraveacircumflexadieresi" +
+ "satildearingccedillaeacuteegraveecircumflexedieresisiacuteigrave" +
+ "icircumflexidieresisntildeoacuteograveocircumflexodieresisotilde" +
+ "uacuteugraveucircumflexudieresisdaggerdegreecentsterlingsectionb" +
+ "ulletparagraphgermandblsregisteredcopyrighttrademarkacutedieresi" +
+ "snotequalAEOslashinfinityplusminuslessequalgreaterequalyenmupart" +
+ "ialdiffsummationproductpiintegralordfeminineordmasculineOmegaaeo" +
+ "slashquestiondownexclamdownlogicalnotradicalflorinapproxequalDel" +
+ "taguillemotleftguillemotrightellipsisnonbreakingspaceAgraveAtild" +
+ "eOtildeOEoeendashemdashquotedblleftquotedblrightquoteleftquoteri" +
+ "ghtdividelozengeydieresisYdieresisfractioncurrencyguilsinglleftg" +
+ "uilsinglrightfifldaggerdblperiodcenteredquotesinglbasequotedblba" +
+ "seperthousandAcircumflexEcircumflexAacuteEdieresisEgraveIacuteIc" +
+ "ircumflexIdieresisIgraveOacuteOcircumflexappleOgraveUacuteUcircu" +
+ "mflexUgravedotlessicircumflextildemacronbrevedotaccentringcedill" +
+ "ahungarumlautogonekcaronLslashlslashScaronscaronZcaronzcaronbrok" +
+ "enbarEthethYacuteyacuteThornthornminusmultiplyonesuperiortwosupe" +
+ "riorthreesuperioronehalfonequarterthreequartersfrancGbrevegbreve" +
+ "IdotaccentScedillascedillaCacutecacuteCcaronccarondcroat"
+
+var builtInPostNamesOffsets = [...]uint16{
+ 0x0000, 0x0007, 0x000c, 0x001c, 0x0021, 0x0027, 0x002f, 0x0039,
+ 0x003f, 0x0046, 0x004f, 0x005a, 0x0063, 0x006d, 0x0075, 0x0079,
+ 0x007e, 0x0084, 0x008a, 0x008f, 0x0093, 0x0096, 0x0099, 0x009e,
+ 0x00a2, 0x00a6, 0x00a9, 0x00ae, 0x00b3, 0x00b7, 0x00bc, 0x00c5,
+ 0x00c9, 0x00ce, 0x00d5, 0x00dd, 0x00df, 0x00e0, 0x00e1, 0x00e2,
+ 0x00e3, 0x00e4, 0x00e5, 0x00e6, 0x00e7, 0x00e8, 0x00e9, 0x00ea,
+ 0x00eb, 0x00ec, 0x00ed, 0x00ee, 0x00ef, 0x00f0, 0x00f1, 0x00f2,
+ 0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00f7, 0x00f8, 0x00f9, 0x0104,
+ 0x010d, 0x0119, 0x0124, 0x012e, 0x0133, 0x0134, 0x0135, 0x0136,
+ 0x0137, 0x0138, 0x0139, 0x013a, 0x013b, 0x013c, 0x013d, 0x013e,
+ 0x013f, 0x0140, 0x0141, 0x0142, 0x0143, 0x0144, 0x0145, 0x0146,
+ 0x0147, 0x0148, 0x0149, 0x014a, 0x014b, 0x014c, 0x014d, 0x0156,
+ 0x0159, 0x0163, 0x016d, 0x0176, 0x017b, 0x0183, 0x0189, 0x018f,
+ 0x0198, 0x01a1, 0x01a7, 0x01ad, 0x01b8, 0x01c1, 0x01c7, 0x01cc,
+ 0x01d4, 0x01da, 0x01e0, 0x01eb, 0x01f4, 0x01fa, 0x0200, 0x020b,
+ 0x0214, 0x021a, 0x0220, 0x0226, 0x0231, 0x023a, 0x0240, 0x0246,
+ 0x024c, 0x0257, 0x0260, 0x0266, 0x026c, 0x0270, 0x0278, 0x027f,
+ 0x0285, 0x028e, 0x0298, 0x02a2, 0x02ab, 0x02b4, 0x02b9, 0x02c1,
+ 0x02c9, 0x02cb, 0x02d1, 0x02d9, 0x02e2, 0x02eb, 0x02f7, 0x02fa,
+ 0x02fc, 0x0307, 0x0310, 0x0317, 0x0319, 0x0321, 0x032c, 0x0338,
+ 0x033d, 0x033f, 0x0345, 0x0351, 0x035b, 0x0365, 0x036c, 0x0372,
+ 0x037d, 0x0382, 0x038f, 0x039d, 0x03a5, 0x03b5, 0x03bb, 0x03c1,
+ 0x03c7, 0x03c9, 0x03cb, 0x03d1, 0x03d7, 0x03e3, 0x03f0, 0x03f9,
+ 0x0403, 0x0409, 0x0410, 0x0419, 0x0422, 0x042a, 0x0432, 0x043f,
+ 0x044d, 0x044f, 0x0451, 0x045a, 0x0468, 0x0476, 0x0482, 0x048d,
+ 0x0498, 0x04a3, 0x04a9, 0x04b2, 0x04b8, 0x04be, 0x04c9, 0x04d2,
+ 0x04d8, 0x04de, 0x04e9, 0x04ee, 0x04f4, 0x04fa, 0x0505, 0x050b,
+ 0x0513, 0x051d, 0x0522, 0x0528, 0x052d, 0x0536, 0x053a, 0x0541,
+ 0x054d, 0x0553, 0x0558, 0x055e, 0x0564, 0x056a, 0x0570, 0x0576,
+ 0x057c, 0x0585, 0x0588, 0x058b, 0x0591, 0x0597, 0x059c, 0x05a1,
+ 0x05a6, 0x05ae, 0x05b9, 0x05c4, 0x05d1, 0x05d8, 0x05e2, 0x05ef,
+ 0x05f4, 0x05fa, 0x0600, 0x060a, 0x0612, 0x061a, 0x0620, 0x0626,
+ 0x062c, 0x0632, 0x0638,
+}
diff --git a/font/sfnt/gen.go b/font/sfnt/gen.go
new file mode 100644
index 0000000..12587d4
--- /dev/null
+++ b/font/sfnt/gen.go
@@ -0,0 +1,321 @@
+// Copyright 2017 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 ignore
+
+package main
+
+import (
+ "bytes"
+ "fmt"
+ "go/format"
+ "io/ioutil"
+ "log"
+)
+
+func main() {
+ data, offsets := []byte(nil), []int{0}
+ for _, name := range names {
+ data = append(data, name...)
+ offsets = append(offsets, len(data))
+ }
+
+ b := new(bytes.Buffer)
+ fmt.Fprintf(b, "// generated by go run gen.go; DO NOT EDIT\n\n")
+ fmt.Fprintf(b, "package sfnt\n\n")
+
+ fmt.Fprintf(b, "const numBuiltInPostNames = %d\n\n", len(names))
+
+ fmt.Fprintf(b, "const builtInPostNamesData = \"\" +\n")
+ for s := data; ; {
+ if len(s) <= 64 {
+ fmt.Fprintf(b, "%q\n", s)
+ break
+ }
+ fmt.Fprintf(b, "%q +\n", s[:64])
+ s = s[64:]
+ }
+ fmt.Fprintf(b, "\n")
+
+ fmt.Fprintf(b, "var builtInPostNamesOffsets = [...]uint16{\n")
+ for i, o := range offsets {
+ fmt.Fprintf(b, "%#04x,", o)
+ if i%8 == 7 {
+ fmt.Fprintf(b, "\n")
+ }
+ }
+ fmt.Fprintf(b, "\n}\n")
+
+ dstUnformatted := b.Bytes()
+ dst, err := format.Source(dstUnformatted)
+ if err != nil {
+ log.Fatalf("format.Source: %v\n\n----\n%s\n----", err, dstUnformatted)
+ }
+ if err := ioutil.WriteFile("data.go", dst, 0666); err != nil {
+ log.Fatalf("ioutil.WriteFile: %v", err)
+ }
+}
+
+// names is the built-in post table names listed at
+// https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6post.html
+var names = [258]string{
+ ".notdef",
+ ".null",
+ "nonmarkingreturn",
+ "space",
+ "exclam",
+ "quotedbl",
+ "numbersign",
+ "dollar",
+ "percent",
+ "ampersand",
+ "quotesingle",
+ "parenleft",
+ "parenright",
+ "asterisk",
+ "plus",
+ "comma",
+ "hyphen",
+ "period",
+ "slash",
+ "zero",
+ "one",
+ "two",
+ "three",
+ "four",
+ "five",
+ "six",
+ "seven",
+ "eight",
+ "nine",
+ "colon",
+ "semicolon",
+ "less",
+ "equal",
+ "greater",
+ "question",
+ "at",
+ "A",
+ "B",
+ "C",
+ "D",
+ "E",
+ "F",
+ "G",
+ "H",
+ "I",
+ "J",
+ "K",
+ "L",
+ "M",
+ "N",
+ "O",
+ "P",
+ "Q",
+ "R",
+ "S",
+ "T",
+ "U",
+ "V",
+ "W",
+ "X",
+ "Y",
+ "Z",
+ "bracketleft",
+ "backslash",
+ "bracketright",
+ "asciicircum",
+ "underscore",
+ "grave",
+ "a",
+ "b",
+ "c",
+ "d",
+ "e",
+ "f",
+ "g",
+ "h",
+ "i",
+ "j",
+ "k",
+ "l",
+ "m",
+ "n",
+ "o",
+ "p",
+ "q",
+ "r",
+ "s",
+ "t",
+ "u",
+ "v",
+ "w",
+ "x",
+ "y",
+ "z",
+ "braceleft",
+ "bar",
+ "braceright",
+ "asciitilde",
+ "Adieresis",
+ "Aring",
+ "Ccedilla",
+ "Eacute",
+ "Ntilde",
+ "Odieresis",
+ "Udieresis",
+ "aacute",
+ "agrave",
+ "acircumflex",
+ "adieresis",
+ "atilde",
+ "aring",
+ "ccedilla",
+ "eacute",
+ "egrave",
+ "ecircumflex",
+ "edieresis",
+ "iacute",
+ "igrave",
+ "icircumflex",
+ "idieresis",
+ "ntilde",
+ "oacute",
+ "ograve",
+ "ocircumflex",
+ "odieresis",
+ "otilde",
+ "uacute",
+ "ugrave",
+ "ucircumflex",
+ "udieresis",
+ "dagger",
+ "degree",
+ "cent",
+ "sterling",
+ "section",
+ "bullet",
+ "paragraph",
+ "germandbls",
+ "registered",
+ "copyright",
+ "trademark",
+ "acute",
+ "dieresis",
+ "notequal",
+ "AE",
+ "Oslash",
+ "infinity",
+ "plusminus",
+ "lessequal",
+ "greaterequal",
+ "yen",
+ "mu",
+ "partialdiff",
+ "summation",
+ "product",
+ "pi",
+ "integral",
+ "ordfeminine",
+ "ordmasculine",
+ "Omega",
+ "ae",
+ "oslash",
+ "questiondown",
+ "exclamdown",
+ "logicalnot",
+ "radical",
+ "florin",
+ "approxequal",
+ "Delta",
+ "guillemotleft",
+ "guillemotright",
+ "ellipsis",
+ "nonbreakingspace",
+ "Agrave",
+ "Atilde",
+ "Otilde",
+ "OE",
+ "oe",
+ "endash",
+ "emdash",
+ "quotedblleft",
+ "quotedblright",
+ "quoteleft",
+ "quoteright",
+ "divide",
+ "lozenge",
+ "ydieresis",
+ "Ydieresis",
+ "fraction",
+ "currency",
+ "guilsinglleft",
+ "guilsinglright",
+ "fi",
+ "fl",
+ "daggerdbl",
+ "periodcentered",
+ "quotesinglbase",
+ "quotedblbase",
+ "perthousand",
+ "Acircumflex",
+ "Ecircumflex",
+ "Aacute",
+ "Edieresis",
+ "Egrave",
+ "Iacute",
+ "Icircumflex",
+ "Idieresis",
+ "Igrave",
+ "Oacute",
+ "Ocircumflex",
+ "apple",
+ "Ograve",
+ "Uacute",
+ "Ucircumflex",
+ "Ugrave",
+ "dotlessi",
+ "circumflex",
+ "tilde",
+ "macron",
+ "breve",
+ "dotaccent",
+ "ring",
+ "cedilla",
+ "hungarumlaut",
+ "ogonek",
+ "caron",
+ "Lslash",
+ "lslash",
+ "Scaron",
+ "scaron",
+ "Zcaron",
+ "zcaron",
+ "brokenbar",
+ "Eth",
+ "eth",
+ "Yacute",
+ "yacute",
+ "Thorn",
+ "thorn",
+ "minus",
+ "multiply",
+ "onesuperior",
+ "twosuperior",
+ "threesuperior",
+ "onehalf",
+ "onequarter",
+ "threequarters",
+ "franc",
+ "Gbreve",
+ "gbreve",
+ "Idotaccent",
+ "Scedilla",
+ "scedilla",
+ "Cacute",
+ "cacute",
+ "Ccaron",
+ "ccaron",
+ "dcroat",
+}
diff --git a/font/sfnt/sfnt.go b/font/sfnt/sfnt.go
index b7f4bdc..995b287 100644
--- a/font/sfnt/sfnt.go
+++ b/font/sfnt/sfnt.go
@@ -2,6 +2,8 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
+//go:generate go run gen.go
+
// Package sfnt implements a decoder for SFNT font file formats, including
// TrueType and OpenType.
package sfnt // import "golang.org/x/image/font/sfnt"
@@ -65,6 +67,7 @@
errInvalidLocationData = errors.New("sfnt: invalid location data")
errInvalidMaxpTable = errors.New("sfnt: invalid maxp table")
errInvalidNameTable = errors.New("sfnt: invalid name table")
+ errInvalidPostTable = errors.New("sfnt: invalid post table")
errInvalidSourceData = errors.New("sfnt: invalid source data")
errInvalidTableOffset = errors.New("sfnt: invalid table offset")
errInvalidTableTagOrder = errors.New("sfnt: invalid table tag order")
@@ -80,6 +83,7 @@
errUnsupportedNumberOfHints = errors.New("sfnt: unsupported number of hints")
errUnsupportedNumberOfTables = errors.New("sfnt: unsupported number of tables")
errUnsupportedPlatformEncoding = errors.New("sfnt: unsupported platform encoding")
+ errUnsupportedPostTable = errors.New("sfnt: unsupported post table")
errUnsupportedTableOffsetLength = errors.New("sfnt: unsupported table offset or length")
errUnsupportedType2Charstring = errors.New("sfnt: unsupported Type 2 Charstring")
)
@@ -217,6 +221,20 @@
return u16(buf), nil
}
+// u32 returns the uint32 in the table t at the relative offset i.
+//
+// buf is an optional scratch buffer as per the source.view method.
+func (s *source) u32(buf []byte, t table, i int) (uint32, error) {
+ if i < 0 || uint(t.length) < uint(i+4) {
+ return 0, errInvalidBounds
+ }
+ buf, err := s.view(buf, int(t.offset)+i, 4)
+ if err != nil {
+ return 0, err
+ }
+ return u32(buf), nil
+}
+
// table is a section of the font data.
type table struct {
offset, length uint32
@@ -298,6 +316,7 @@
glyphIndex func(f *Font, b *Buffer, r rune) (GlyphIndex, error)
indexToLocFormat bool // false means short, true means long.
isPostScript bool
+ postTableVersion uint32
unitsPerEm Units
// The glyph data for the glyph index i is in
@@ -320,6 +339,13 @@
if err != nil {
return err
}
+
+ // The order of these parseXxx calls matters. Later calls may depend on
+ // f.cached state set up by earlier calls, such as the number of glyphs in
+ // the font being parsed by parseMaxp.
+
+ // TODO: make state dependencies explicit instead of implicit.
+
buf, err = f.parseHead(buf)
if err != nil {
return err
@@ -332,6 +358,10 @@
if err != nil {
return err
}
+ buf, err = f.parsePost(buf)
+ if err != nil {
+ return err
+ }
return nil
}
@@ -538,6 +568,31 @@
return buf, nil
}
+func (f *Font) parsePost(buf []byte) ([]byte, error) {
+ // https://www.microsoft.com/typography/otspec/post.htm
+
+ const headerSize = 32
+ if f.post.length < headerSize {
+ return nil, errInvalidPostTable
+ }
+ u, err := f.src.u32(buf, f.post, 0)
+ if err != nil {
+ return nil, err
+ }
+ switch u {
+ case 0x20000:
+ if f.post.length < headerSize+2+2*uint32(f.NumGlyphs()) {
+ return nil, errInvalidPostTable
+ }
+ case 0x30000:
+ // No-op.
+ default:
+ return nil, errUnsupportedPostTable
+ }
+ f.cached.postTableVersion = u
+ return buf, nil
+}
+
// TODO: API for looking up glyph variants?? For example, some fonts may
// provide both slashed and dotted zero glyphs ('0'), or regular and 'old
// style' numerals, and users can direct software to choose a variant.
@@ -606,6 +661,78 @@
return b.segments, nil
}
+// GlyphName returns the name of the x'th glyph.
+//
+// Not every font contains glyph names. If not present, GlyphName will return
+// ("", nil).
+//
+// If present, the glyph name, provided by the font, is assumed to follow the
+// Adobe Glyph List Specification:
+// https://github.com/adobe-type-tools/agl-specification/blob/master/README.md
+//
+// This is also known as the "Adobe Glyph Naming convention", the "Adobe
+// document [for] Unicode and Glyph Names" or "PostScript glyph names".
+//
+// It returns ErrNotFound if the glyph index is out of range.
+func (f *Font) GlyphName(b *Buffer, x GlyphIndex) (string, error) {
+ if int(x) >= f.NumGlyphs() {
+ return "", ErrNotFound
+ }
+ if f.cached.postTableVersion != 0x20000 {
+ return "", nil
+ }
+ if b == nil {
+ b = &Buffer{}
+ }
+
+ // The wire format for a Version 2 post table is documented at:
+ // https://www.microsoft.com/typography/otspec/post.htm
+ const glyphNameIndexOffset = 34
+
+ buf, err := b.view(&f.src, int(f.post.offset)+glyphNameIndexOffset+2*int(x), 2)
+ if err != nil {
+ return "", err
+ }
+ u := u16(buf)
+ if u < numBuiltInPostNames {
+ i := builtInPostNamesOffsets[u+0]
+ j := builtInPostNamesOffsets[u+1]
+ return builtInPostNamesData[i:j], nil
+ }
+ // https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6post.html
+ // says that "32768 through 65535 are reserved for future use".
+ if u > 32767 {
+ return "", errUnsupportedPostTable
+ }
+ u -= numBuiltInPostNames
+
+ // Iterate through the list of Pascal-formatted strings. A linear scan is
+ // clearly O(u), which isn't great (as the obvious loop, calling
+ // Font.GlyphName, to get all of the glyph names in a font has quadratic
+ // complexity), but the wire format doesn't suggest a better alternative.
+
+ offset := glyphNameIndexOffset + 2*f.NumGlyphs()
+ buf, err = b.view(&f.src, int(f.post.offset)+offset, int(f.post.length)-offset)
+ if err != nil {
+ return "", err
+ }
+
+ for {
+ if len(buf) == 0 {
+ return "", errInvalidPostTable
+ }
+ n := 1 + int(buf[0])
+ if len(buf) < n {
+ return "", errInvalidPostTable
+ }
+ if u == 0 {
+ return string(buf[1:n]), nil
+ }
+ buf = buf[n:]
+ u--
+ }
+}
+
// Name returns the name value keyed by the given NameID.
//
// It returns ErrNotFound if there is no value for that key.
diff --git a/font/sfnt/sfnt_test.go b/font/sfnt/sfnt_test.go
index c6d6741..ca30321 100644
--- a/font/sfnt/sfnt_test.go
+++ b/font/sfnt/sfnt_test.go
@@ -431,3 +431,77 @@
t.Errorf("Name:\ngot %q\nwant %q", name, want)
}
}
+
+func TestGlyphName(t *testing.T) {
+ f, err := Parse(goregular.TTF)
+ if err != nil {
+ t.Fatalf("Parse: %v", err)
+ }
+
+ testCases := []struct {
+ r rune
+ want string
+ }{
+ {'\x00', "NULL"},
+ {'!', "exclam"},
+ {'A', "A"},
+ {'{', "braceleft"},
+ {'\u00c4', "Adieresis"}, // U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS
+ {'\u2020', "dagger"}, // U+2020 DAGGER
+ {'\u2660', "spade"}, // U+2660 BLACK SPADE SUIT
+ {'\uf800', "gopher"}, // U+F800 <Private Use>
+ {'\ufffe', ".notdef"}, // Not in the Go Regular font, so GlyphIndex returns (0, nil).
+ }
+
+ var b Buffer
+ for _, tc := range testCases {
+ x, err := f.GlyphIndex(&b, tc.r)
+ if err != nil {
+ t.Errorf("r=%q: GlyphIndex: %v", tc.r, err)
+ continue
+ }
+ got, err := f.GlyphName(&b, x)
+ if err != nil {
+ t.Errorf("r=%q: GlyphName: %v", tc.r, err)
+ continue
+ }
+ if got != tc.want {
+ t.Errorf("r=%q: got %q, want %q", tc.r, got, tc.want)
+ continue
+ }
+ }
+}
+
+func TestBuiltInPostNames(t *testing.T) {
+ testCases := []struct {
+ x GlyphIndex
+ want string
+ }{
+ {0, ".notdef"},
+ {1, ".null"},
+ {2, "nonmarkingreturn"},
+ {13, "asterisk"},
+ {36, "A"},
+ {93, "z"},
+ {123, "ocircumflex"},
+ {202, "Edieresis"},
+ {255, "Ccaron"},
+ {256, "ccaron"},
+ {257, "dcroat"},
+ {258, ""},
+ {999, ""},
+ {0xffff, ""},
+ }
+
+ for _, tc := range testCases {
+ if tc.x >= numBuiltInPostNames {
+ continue
+ }
+ i := builtInPostNamesOffsets[tc.x+0]
+ j := builtInPostNamesOffsets[tc.x+1]
+ got := builtInPostNamesData[i:j]
+ if got != tc.want {
+ t.Errorf("x=%d: got %q, want %q", tc.x, got, tc.want)
+ }
+ }
+}
