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Diffstat (limited to 'vendor/golang.org/x/image/font/sfnt/sfnt.go')
-rw-r--r--vendor/golang.org/x/image/font/sfnt/sfnt.go292
1 files changed, 229 insertions, 63 deletions
diff --git a/vendor/golang.org/x/image/font/sfnt/sfnt.go b/vendor/golang.org/x/image/font/sfnt/sfnt.go
index 02efd5f3a..356841db1 100644
--- a/vendor/golang.org/x/image/font/sfnt/sfnt.go
+++ b/vendor/golang.org/x/image/font/sfnt/sfnt.go
@@ -45,10 +45,17 @@ const (
// safe to call concurrently, as long as each call has a different *Buffer.
maxCmapSegments = 20000
- maxGlyphDataLength = 64 * 1024
- maxHintBits = 256
- maxNumTables = 256
- maxRealNumberStrLen = 64 // Maximum length in bytes of the "-123.456E-7" representation.
+ // TODO: similarly, load subroutine locations lazily. Adobe's
+ // SourceHanSansSC-Regular.otf has up to 30000 subroutines.
+ maxNumSubroutines = 40000
+
+ maxCompoundRecursionDepth = 8
+ maxCompoundStackSize = 64
+ maxGlyphDataLength = 64 * 1024
+ maxHintBits = 256
+ maxNumFonts = 256
+ maxNumTables = 256
+ maxRealNumberStrLen = 64 // Maximum length in bytes of the "-123.456E-7" representation.
// (maxTableOffset + maxTableLength) will not overflow an int32.
maxTableLength = 1 << 29
@@ -59,22 +66,25 @@ var (
// ErrNotFound indicates that the requested value was not found.
ErrNotFound = errors.New("sfnt: not found")
- errInvalidBounds = errors.New("sfnt: invalid bounds")
- errInvalidCFFTable = errors.New("sfnt: invalid CFF table")
- errInvalidCmapTable = errors.New("sfnt: invalid cmap table")
- errInvalidGlyphData = errors.New("sfnt: invalid glyph data")
- errInvalidHeadTable = errors.New("sfnt: invalid head table")
- errInvalidKernTable = errors.New("sfnt: invalid kern table")
- errInvalidLocaTable = errors.New("sfnt: invalid loca table")
- 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")
- errInvalidUCS2String = errors.New("sfnt: invalid UCS-2 string")
- errInvalidVersion = errors.New("sfnt: invalid version")
+ errInvalidBounds = errors.New("sfnt: invalid bounds")
+ errInvalidCFFTable = errors.New("sfnt: invalid CFF table")
+ errInvalidCmapTable = errors.New("sfnt: invalid cmap table")
+ errInvalidFont = errors.New("sfnt: invalid font")
+ errInvalidFontCollection = errors.New("sfnt: invalid font collection")
+ errInvalidGlyphData = errors.New("sfnt: invalid glyph data")
+ errInvalidGlyphDataLength = errors.New("sfnt: invalid glyph data length")
+ errInvalidHeadTable = errors.New("sfnt: invalid head table")
+ errInvalidKernTable = errors.New("sfnt: invalid kern table")
+ errInvalidLocaTable = errors.New("sfnt: invalid loca table")
+ 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")
+ errInvalidSingleFont = errors.New("sfnt: invalid single font (data is a font collection)")
+ errInvalidSourceData = errors.New("sfnt: invalid source data")
+ errInvalidTableOffset = errors.New("sfnt: invalid table offset")
+ errInvalidTableTagOrder = errors.New("sfnt: invalid table tag order")
+ errInvalidUCS2String = errors.New("sfnt: invalid UCS-2 string")
errUnsupportedCFFVersion = errors.New("sfnt: unsupported CFF version")
errUnsupportedCmapEncodings = errors.New("sfnt: unsupported cmap encodings")
@@ -83,7 +93,9 @@ var (
errUnsupportedKernTable = errors.New("sfnt: unsupported kern table")
errUnsupportedRealNumberEncoding = errors.New("sfnt: unsupported real number encoding")
errUnsupportedNumberOfCmapSegments = errors.New("sfnt: unsupported number of cmap segments")
+ errUnsupportedNumberOfFonts = errors.New("sfnt: unsupported number of fonts")
errUnsupportedNumberOfHints = errors.New("sfnt: unsupported number of hints")
+ errUnsupportedNumberOfSubroutines = errors.New("sfnt: unsupported number of subroutines")
errUnsupportedNumberOfTables = errors.New("sfnt: unsupported number of tables")
errUnsupportedPlatformEncoding = errors.New("sfnt: unsupported platform encoding")
errUnsupportedPostTable = errors.New("sfnt: unsupported post table")
@@ -254,19 +266,105 @@ type table struct {
offset, length uint32
}
-// Parse parses an SFNT font from a []byte data source.
+// ParseCollection parses an SFNT font collection, such as TTC or OTC data,
+// from a []byte data source.
+//
+// If passed data for a single font, a TTF or OTF instead of a TTC or OTC, it
+// will return a collection containing 1 font.
+func ParseCollection(src []byte) (*Collection, error) {
+ c := &Collection{src: source{b: src}}
+ if err := c.initialize(); err != nil {
+ return nil, err
+ }
+ return c, nil
+}
+
+// ParseCollectionReaderAt parses an SFNT collection, such as TTC or OTC data,
+// from an io.ReaderAt data source.
+//
+// If passed data for a single font, a TTF or OTF instead of a TTC or OTC, it
+// will return a collection containing 1 font.
+func ParseCollectionReaderAt(src io.ReaderAt) (*Collection, error) {
+ c := &Collection{src: source{r: src}}
+ if err := c.initialize(); err != nil {
+ return nil, err
+ }
+ return c, nil
+}
+
+// Collection is a collection of one or more fonts.
+//
+// All of the Collection methods are safe to call concurrently.
+type Collection struct {
+ src source
+ offsets []uint32
+}
+
+// NumFonts returns the number of fonts in the collection.
+func (c *Collection) NumFonts() int { return len(c.offsets) }
+
+func (c *Collection) initialize() error {
+ // The https://www.microsoft.com/typography/otspec/otff.htm "Font
+ // Collections" section describes the TTC Header.
+ buf, err := c.src.view(nil, 0, 12)
+ if err != nil {
+ return err
+ }
+ // These cases match the switch statement in Font.initializeTables.
+ switch u32(buf) {
+ default:
+ return errInvalidFontCollection
+ case 0x00010000, 0x4f54544f:
+ // Try parsing it as a single font instead of a collection.
+ c.offsets = []uint32{0}
+ case 0x74746366: // "ttcf".
+ numFonts := u32(buf[8:])
+ if numFonts == 0 || numFonts > maxNumFonts {
+ return errUnsupportedNumberOfFonts
+ }
+ buf, err = c.src.view(nil, 12, int(4*numFonts))
+ if err != nil {
+ return err
+ }
+ c.offsets = make([]uint32, numFonts)
+ for i := range c.offsets {
+ o := u32(buf[4*i:])
+ if o > maxTableOffset {
+ return errUnsupportedTableOffsetLength
+ }
+ c.offsets[i] = o
+ }
+ }
+ return nil
+}
+
+// Font returns the i'th font in the collection.
+func (c *Collection) Font(i int) (*Font, error) {
+ if i < 0 || len(c.offsets) <= i {
+ return nil, ErrNotFound
+ }
+ f := &Font{src: c.src}
+ if err := f.initialize(int(c.offsets[i])); err != nil {
+ return nil, err
+ }
+ return f, nil
+}
+
+// Parse parses an SFNT font, such as TTF or OTF data, from a []byte data
+// source.
func Parse(src []byte) (*Font, error) {
f := &Font{src: source{b: src}}
- if err := f.initialize(); err != nil {
+ if err := f.initialize(0); err != nil {
return nil, err
}
return f, nil
}
-// ParseReaderAt parses an SFNT font from an io.ReaderAt data source.
+// ParseReaderAt parses an SFNT font, such as TTF or OTF data, from an
+// io.ReaderAt data source.
func ParseReaderAt(src io.ReaderAt) (*Font, error) {
f := &Font{src: source{r: src}}
- if err := f.initialize(); err != nil {
+ if err := f.initialize(0); err != nil {
return nil, err
}
return f, nil
@@ -348,9 +446,17 @@ type Font struct {
postTableVersion uint32
unitsPerEm Units
- // The glyph data for the glyph index i is in
+ // The glyph data for the i'th glyph index is in
// src[locations[i+0]:locations[i+1]].
+ //
+ // The slice length equals 1 plus the number of glyphs.
locations []uint32
+
+ // For PostScript fonts, the bytecode for the i'th global or local
+ // subroutine is in src[x[i+0]:x[i+1]].
+ //
+ // The slice length equals 1 plus the number of subroutines
+ gsubrs, subrs []uint32
}
}
@@ -360,11 +466,11 @@ func (f *Font) NumGlyphs() int { return len(f.cached.locations) - 1 }
// UnitsPerEm returns the number of units per em for f.
func (f *Font) UnitsPerEm() Units { return f.cached.unitsPerEm }
-func (f *Font) initialize() error {
+func (f *Font) initialize(offset int) error {
if !f.src.valid() {
return errInvalidSourceData
}
- buf, isPostScript, err := f.initializeTables(nil)
+ buf, isPostScript, err := f.initializeTables(offset)
if err != nil {
return err
}
@@ -381,7 +487,7 @@ func (f *Font) initialize() error {
if err != nil {
return err
}
- buf, numGlyphs, locations, err := f.parseMaxp(buf, indexToLocFormat, isPostScript)
+ buf, numGlyphs, locations, gsubrs, subrs, err := f.parseMaxp(buf, indexToLocFormat, isPostScript)
if err != nil {
return err
}
@@ -406,25 +512,31 @@ func (f *Font) initialize() error {
f.cached.postTableVersion = postTableVersion
f.cached.unitsPerEm = unitsPerEm
f.cached.locations = locations
+ f.cached.gsubrs = gsubrs
+ f.cached.subrs = subrs
return nil
}
-func (f *Font) initializeTables(buf []byte) (buf1 []byte, isPostScript bool, err error) {
+func (f *Font) initializeTables(offset int) (buf1 []byte, isPostScript bool, err error) {
// https://www.microsoft.com/typography/otspec/otff.htm "Organization of an
// OpenType Font" says that "The OpenType font starts with the Offset
// Table", which is 12 bytes.
- buf, err = f.src.view(buf, 0, 12)
+ buf, err := f.src.view(nil, offset, 12)
if err != nil {
return nil, false, err
}
+ // When updating the cases in this switch statement, also update the
+ // Collection.initialize method.
switch u32(buf) {
default:
- return nil, false, errInvalidVersion
+ return nil, false, errInvalidFont
case 0x00010000:
// No-op.
case 0x4f54544f: // "OTTO".
isPostScript = true
+ case 0x74746366: // "ttcf".
+ return nil, false, errInvalidSingleFont
}
numTables := int(u16(buf[4:]))
if numTables > maxNumTables {
@@ -433,7 +545,7 @@ func (f *Font) initializeTables(buf []byte) (buf1 []byte, isPostScript bool, err
// "The Offset Table is followed immediately by the Table Record entries...
// sorted in ascending order by tag", 16 bytes each.
- buf, err = f.src.view(buf, 12, 16*numTables)
+ buf, err = f.src.view(buf, offset+12, 16*numTables)
if err != nil {
return nil, false, err
}
@@ -597,10 +709,20 @@ func (f *Font) parseKern(buf []byte) (buf1 []byte, kernNumPairs, kernOffset int3
}
return f.parseKernVersion0(buf, offset, length)
case 1:
- // TODO: find such a (proprietary?) font, and support it. Both of
- // https://www.microsoft.com/typography/otspec/kern.htm
+ if buf[2] != 0 || buf[3] != 0 {
+ return nil, 0, 0, errUnsupportedKernTable
+ }
+ // Microsoft's https://www.microsoft.com/typography/otspec/kern.htm
+ // says that "Apple has extended the definition of the 'kern' table to
+ // provide additional functionality. The Apple extensions are not
+ // supported on Windows."
+ //
+ // The format is relatively complicated, including encoding a state
+ // machine, but rarely seen. We follow Microsoft's and FreeType's
+ // behavior and simply ignore it. Theoretically, we could follow
// https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6kern.html
- // say that such fonts work on Mac OS but not on Windows.
+ // but it doesn't seem worth the effort.
+ return buf, 0, 0, nil
}
return nil, 0, 0, errUnsupportedKernTable
}
@@ -633,7 +755,9 @@ func (f *Font) parseKernVersion0(buf []byte, offset, length int) (buf1 []byte, k
case 0:
return f.parseKernFormat0(buf, offset, subtableLength)
case 2:
- // TODO: find such a (proprietary?) font, and support it.
+ // If we could find such a font, we could write code to support it, but
+ // a comment in the equivalent FreeType code (sfnt/ttkern.c) says that
+ // they've never seen such a font.
}
return nil, 0, 0, errUnsupportedKernTable
}
@@ -654,21 +778,21 @@ func (f *Font) parseKernFormat0(buf []byte, offset, length int) (buf1 []byte, ke
return buf, kernNumPairs, int32(offset) + headerSize, nil
}
-func (f *Font) parseMaxp(buf []byte, indexToLocFormat, isPostScript bool) (buf1 []byte, numGlyphs int, locations []uint32, err error) {
+func (f *Font) parseMaxp(buf []byte, indexToLocFormat, isPostScript bool) (buf1 []byte, numGlyphs int, locations, gsubrs, subrs []uint32, err error) {
// https://www.microsoft.com/typography/otspec/maxp.htm
if isPostScript {
if f.maxp.length != 6 {
- return nil, 0, nil, errInvalidMaxpTable
+ return nil, 0, nil, nil, nil, errInvalidMaxpTable
}
} else {
if f.maxp.length != 32 {
- return nil, 0, nil, errInvalidMaxpTable
+ return nil, 0, nil, nil, nil, errInvalidMaxpTable
}
}
u, err := f.src.u16(buf, f.maxp, 4)
if err != nil {
- return nil, 0, nil, err
+ return nil, 0, nil, nil, nil, err
}
numGlyphs = int(u)
@@ -679,21 +803,21 @@ func (f *Font) parseMaxp(buf []byte, indexToLocFormat, isPostScript bool) (buf1
offset: int(f.cff.offset),
end: int(f.cff.offset + f.cff.length),
}
- locations, err = p.parse()
+ locations, gsubrs, subrs, err = p.parse()
if err != nil {
- return nil, 0, nil, err
+ return nil, 0, nil, nil, nil, err
}
} else {
locations, err = parseLoca(&f.src, f.loca, f.glyf.offset, indexToLocFormat, numGlyphs)
if err != nil {
- return nil, 0, nil, err
+ return nil, 0, nil, nil, nil, err
}
}
if len(locations) != numGlyphs+1 {
- return nil, 0, nil, errInvalidLocationData
+ return nil, 0, nil, nil, nil, errInvalidLocationData
}
- return buf, numGlyphs, locations, nil
+ return buf, numGlyphs, locations, gsubrs, subrs, nil
}
func (f *Font) parsePost(buf []byte, numGlyphs int) (buf1 []byte, postTableVersion uint32, err error) {
@@ -737,17 +861,21 @@ func (f *Font) GlyphIndex(b *Buffer, r rune) (GlyphIndex, error) {
return f.cached.glyphIndex(f, b, r)
}
-func (f *Font) viewGlyphData(b *Buffer, x GlyphIndex) ([]byte, error) {
+func (f *Font) viewGlyphData(b *Buffer, x GlyphIndex) (buf []byte, offset, length uint32, err error) {
xx := int(x)
if f.NumGlyphs() <= xx {
- return nil, ErrNotFound
+ return nil, 0, 0, ErrNotFound
}
i := f.cached.locations[xx+0]
j := f.cached.locations[xx+1]
+ if j < i {
+ return nil, 0, 0, errInvalidGlyphDataLength
+ }
if j-i > maxGlyphDataLength {
- return nil, errUnsupportedGlyphDataLength
+ return nil, 0, 0, errUnsupportedGlyphDataLength
}
- return b.view(&f.src, int(i), int(j-i))
+ buf, err = b.view(&f.src, int(i), int(j-i))
+ return buf, i, j - i, err
}
// LoadGlyphOptions are the options to the Font.LoadGlyph method.
@@ -766,24 +894,23 @@ func (f *Font) LoadGlyph(b *Buffer, x GlyphIndex, ppem fixed.Int26_6, opts *Load
b = &Buffer{}
}
- buf, err := f.viewGlyphData(b, x)
- if err != nil {
- return nil, err
- }
-
b.segments = b.segments[:0]
if f.cached.isPostScript {
- b.psi.type2Charstrings.initialize(b.segments)
- if err := b.psi.run(psContextType2Charstring, buf); err != nil {
+ buf, offset, length, err := f.viewGlyphData(b, x)
+ if err != nil {
+ return nil, err
+ }
+ b.psi.type2Charstrings.initialize(f, b)
+ if err := b.psi.run(psContextType2Charstring, buf, offset, length); err != nil {
return nil, err
}
- b.segments = b.psi.type2Charstrings.segments
+ if !b.psi.type2Charstrings.ended {
+ return nil, errInvalidCFFTable
+ }
} else {
- segments, err := appendGlyfSegments(b.segments, buf)
- if err != nil {
+ if err := loadGlyf(f, b, x, 0, 0); err != nil {
return nil, err
}
- b.segments = segments
}
// Scale the segments. If we want to support hinting, we'll have to push
@@ -889,9 +1016,9 @@ func (f *Font) Kern(b *Buffer, x0, x1 GlyphIndex, ppem fixed.Int26_6, h font.Hin
if n := f.NumGlyphs(); int(x0) >= n || int(x1) >= n {
return 0, ErrNotFound
}
- // Not every font has a kern table. If it doesn't, there's no need to
- // allocate a Buffer.
- if f.kern.length == 0 {
+ // Not every font has a kern table. If it doesn't, or if that table is
+ // ignored, there's no need to allocate a Buffer.
+ if f.cached.kernNumPairs == 0 {
return 0, nil
}
if b == nil {
@@ -1024,6 +1151,16 @@ type Buffer struct {
buf []byte
// segments holds glyph vector path segments.
segments []Segment
+ // compoundStack holds the components of a TrueType compound glyph.
+ compoundStack [maxCompoundStackSize]struct {
+ glyphIndex GlyphIndex
+ dx, dy int16
+ hasTransform bool
+ transformXX int16
+ transformXY int16
+ transformYX int16
+ transformYY int16
+ }
// psi is a PostScript interpreter for when the Font is an OpenType/CFF
// font.
psi psInterpreter
@@ -1056,3 +1193,32 @@ const (
SegmentOpQuadTo
SegmentOpCubeTo
)
+
+// translateArgs applies a translation to args.
+func translateArgs(args *[6]fixed.Int26_6, dx, dy fixed.Int26_6) {
+ args[0] += dx
+ args[1] += dy
+ args[2] += dx
+ args[3] += dy
+ args[4] += dx
+ args[5] += dy
+}
+
+// transformArgs applies an affine transformation to args. The t?? arguments
+// are 2.14 fixed point values.
+func transformArgs(args *[6]fixed.Int26_6, txx, txy, tyx, tyy int16, dx, dy fixed.Int26_6) {
+ args[0], args[1] = tform(txx, txy, tyx, tyy, dx, dy, args[0], args[1])
+ args[2], args[3] = tform(txx, txy, tyx, tyy, dx, dy, args[2], args[3])
+ args[4], args[5] = tform(txx, txy, tyx, tyy, dx, dy, args[4], args[5])
+}
+
+func tform(txx, txy, tyx, tyy int16, dx, dy, x, y fixed.Int26_6) (newX, newY fixed.Int26_6) {
+ const half = 1 << 13
+ newX = dx +
+ fixed.Int26_6((int64(x)*int64(txx)+half)>>14) +
+ fixed.Int26_6((int64(y)*int64(tyx)+half)>>14)
+ newY = dy +
+ fixed.Int26_6((int64(x)*int64(txy)+half)>>14) +
+ fixed.Int26_6((int64(y)*int64(tyy)+half)>>14)
+ return newX, newY
+}
generated by cgit v1.2.3-1-g7c22 (git 2.25.1) at 2024-06-27 20:59:48 +0000