font/sfnt: implement implicit vstem before hintmask.
Change-Id: I811bcf94b518dabcfbebd085ad3c6a47c17ef38e
Reviewed-on: https://go-review.googlesource.com/38288
Reviewed-by: David Crawshaw <crawshaw@golang.org>
diff --git a/font/sfnt/postscript.go b/font/sfnt/postscript.go
index 60a8294..5506819 100644
--- a/font/sfnt/postscript.go
+++ b/font/sfnt/postscript.go
@@ -762,7 +762,8 @@
const escapeByte = 12
// t2CReadWidth reads the optional width adjustment. If present, it is on the
-// bottom of the stack.
+// bottom of the arg stack. nArgs is the expected number of arguments on the
+// stack. A negative nArgs means a multiple of 2.
//
// 5177.Type2.pdf page 16 Note 4 says: "The first stack-clearing operator,
// which must be one of hstem, hstemhm, vstem, vstemhm, cntrmask, hintmask,
@@ -773,19 +774,12 @@
return
}
p.type2Charstrings.seenWidth = true
- switch nArgs {
- case 0:
- if p.argStack.top != 1 {
+ if nArgs >= 0 {
+ if p.argStack.top != nArgs+1 {
return
}
- case 1:
- if p.argStack.top <= 1 {
- return
- }
- default:
- if p.argStack.top%nArgs != 1 {
- return
- }
+ } else if p.argStack.top&1 == 0 {
+ return
}
// When parsing a standalone CFF, we'd save the value of p.argStack.a[0]
// here as it defines the glyph's width (horizontal advance). Specifically,
@@ -803,7 +797,7 @@
}
func t2CStem(p *psInterpreter) error {
- t2CReadWidth(p, 2)
+ t2CReadWidth(p, -1)
if p.argStack.top%2 != 0 {
return errInvalidCFFTable
}
@@ -818,8 +812,27 @@
}
func t2CMask(p *psInterpreter) error {
+ // 5176.CFF.pdf section 4.3 "Hint Operators" says that "If hstem and vstem
+ // hints are both declared at the beginning of a charstring, and this
+ // sequence is followed directly by the hintmask or cntrmask operators, the
+ // vstem hint operator need not be included."
+ //
+ // What we implement here is more permissive (but the same as what the
+ // FreeType implementation does, and simpler than tracking the previous
+ // operator and other hinting state): if a hintmask is given any arguments
+ // (i.e. the argStack is non-empty), we run an implicit vstem operator.
+ //
+ // Note that the vstem operator consumes from p.argStack, but the hintmask
+ // or cntrmask operators consume from p.instructions.
+ if p.argStack.top != 0 {
+ if err := t2CStem(p); err != nil {
+ return err
+ }
+ } else if !p.type2Charstrings.seenWidth {
+ p.type2Charstrings.seenWidth = true
+ }
+
hintBytes := (p.type2Charstrings.hintBits + 7) / 8
- t2CReadWidth(p, hintBytes)
if len(p.instructions) < int(hintBytes) {
return errInvalidCFFTable
}
diff --git a/font/sfnt/proprietary_test.go b/font/sfnt/proprietary_test.go
index ccf013d..bf26719 100644
--- a/font/sfnt/proprietary_test.go
+++ b/font/sfnt/proprietary_test.go
@@ -80,7 +80,7 @@
)
func TestProprietaryAdobeSourceCodeProOTF(t *testing.T) {
- testProprietary(t, "adobe", "SourceCodePro-Regular.otf", 1500, 34)
+ testProprietary(t, "adobe", "SourceCodePro-Regular.otf", 1500, -1)
}
func TestProprietaryAdobeSourceCodeProTTF(t *testing.T) {
@@ -92,7 +92,7 @@
}
func TestProprietaryAdobeSourceSansProOTF(t *testing.T) {
- testProprietary(t, "adobe", "SourceSansPro-Regular.otf", 1800, 34)
+ testProprietary(t, "adobe", "SourceSansPro-Regular.otf", 1800, -1)
}
func TestProprietaryAdobeSourceSansProTTF(t *testing.T) {
@@ -112,11 +112,11 @@
}
func TestProprietaryAppleHiragino0(t *testing.T) {
- testProprietary(t, "apple", "ヒラギノ角ゴシック W0.ttc?0", 9000, 6)
+ testProprietary(t, "apple", "ヒラギノ角ゴシック W0.ttc?0", 9000, -1)
}
func TestProprietaryAppleHiragino1(t *testing.T) {
- testProprietary(t, "apple", "ヒラギノ角ゴシック W0.ttc?1", 9000, 6)
+ testProprietary(t, "apple", "ヒラギノ角ゴシック W0.ttc?1", 9000, -1)
}
func TestProprietaryMicrosoftArial(t *testing.T) {
@@ -442,13 +442,14 @@
// proprietaryGlyphTestCases hold a sample of each font's glyph vectors. The
// numerical values can be verified by running the ttx tool, remembering that:
-// - for PostScript glyphs, ttx coordinates are relative, and hstem / vstem
-// operators are hinting-related and can be ignored.
+// - for PostScript glyphs, ttx coordinates are relative.
// - for TrueType glyphs, ttx coordinates are absolute, and consecutive
// off-curve points implies an on-curve point at the midpoint.
var proprietaryGlyphTestCases = map[string]map[rune][]Segment{
"adobe/SourceSansPro-Regular.otf": {
',': {
+ // -309 -1 115 hstem
+ // 137 61 vstem
// 67 -170 rmoveto
moveTo(67, -170),
// 81 34 50 67 86 vvcurveto
@@ -464,6 +465,8 @@
},
'Q': {
+ // 106 -165 70 87 65 538 73 hstem
+ // 52 86 388 87 vstem
// 332 57 rmoveto
moveTo(332, 57),
// -117 -77 106 168 163 77 101 117 117 77 -101 -163 -168 -77 -106 -117 hvcurveto
@@ -492,6 +495,77 @@
// endchar
},
+ 'ĩ': { // U+0129 LATIN SMALL LETTER I WITH TILDE
+ // 92 callgsubr # 92 + bias = 199.
+ // : # Arg stack is [].
+ // : -312 21 85 callgsubr # 85 + bias = 192.
+ // : : # Arg stack is [-312 21].
+ // : : -21 486 -20 return
+ // : : # Arg stack is [-312 21 -21 486 -20].
+ // : return
+ // : # Arg stack is [-312 21 -21 486 -20].
+ // 111 45 callsubr # 45 + bias = 152
+ // : # Arg stack is [-312 21 -21 486 -20 111].
+ // : 60 24 60 -9 216 callgsubr # 216 + bias = 323
+ // : : # Arg stack is [-312 21 -21 486 -20 111 60 24 60 -9].
+ // : : -20 24 -20 hstemhm
+ // : : return
+ // : : # Arg stack is [].
+ // : return
+ // : # Arg stack is [].
+ // -50 55 77 82 77 55 hintmask 1101000100000000
+ // 134 callsubr # 134 + bias = 241
+ // : # Arg stack is [].
+ // : 82 hmoveto
+ moveTo(82, 0),
+ // : 82 127 callsubr # 127 + bias = 234
+ // : : # Arg stack is [82].
+ // : : 486 -82 hlineto
+ lineTo(164, 0),
+ lineTo(164, 486),
+ lineTo(82, 486),
+ // : : return
+ // : : # Arg stack is [].
+ // : return
+ // : # Arg stack is [].
+ // hintmask 1110100110000000
+ // 113 91 15 callgsubr # 15 + bias = 122
+ // : # Arg stack is [113 91].
+ // : rmoveto
+ moveTo(195, 577),
+ // : 69 29 58 77 3 hvcurveto
+ cubeTo(264, 577, 293, 635, 296, 712),
+ // : return
+ // : # Arg stack is [].
+ // hintmask 1110010110000000
+ // -58 callsubr # -58 + bias = 49
+ // : # Arg stack is [].
+ // : -55 4 rlineto
+ lineTo(241, 716),
+ // : -46 -3 -14 -33 -29 -47 -26 84 -71 hhcurveto
+ cubeTo(238, 670, 224, 637, 195, 637),
+ cubeTo(148, 637, 122, 721, 51, 721),
+ // : return
+ // : # Arg stack is [].
+ // hintmask 1101001100000000
+ // -70 callgsubr # -70 + bias = 37
+ // : # Arg stack is [].
+ // : -69 -29 -58 -78 -3 hvcurveto
+ cubeTo(-18, 721, -47, 663, -50, 585),
+ // : 55 -3 rlineto
+ lineTo(5, 582),
+ // : 47 3 14 32 30 hhcurveto
+ cubeTo(8, 629, 22, 661, 52, 661),
+ // : return
+ // : # Arg stack is [].
+ // hintmask 1110100110000000
+ // 51 callsubr # 51 + bias = 158
+ // : # Arg stack is [].
+ // : 46 26 -84 71 hhcurveto
+ cubeTo(98, 661, 124, 577, 195, 577),
+ // : endchar
+ },
+
'ī': { // U+012B LATIN SMALL LETTER I WITH MACRON
// 92 callgsubr # 92 + bias = 199.
// : # Arg stack is [].
@@ -587,6 +661,8 @@
},
'Λ': { // U+039B GREEK CAPITAL LETTER LAMDA
+ // -43 21 -21 572 84 hstem
+ // 0 515 vstem
// 0 vmoveto
moveTo(0, 0),
// 85 hlineto
@@ -607,6 +683,77 @@
lineTo(209, 656),
// endchar
},
+
+ 'Ḫ': { // U+1E2A LATIN CAPITAL LETTER H WITH BREVE BELOW
+ // 94 -231 55 197 157 callgsubr # 157 + bias = 264
+ // : # Arg stack is [94 -231 55 197].
+ // : -21 309 72 return
+ // : # Arg stack is [94 -231 55 197 -21 309 72].
+ // 275 254 callgsubr # 254 + bias = 361
+ // : # Arg stack is [94 -231 55 197 -21 309 72 275].
+ // : -20 hstemhm
+ // : 90 83 return
+ // : # Arg stack is [90 83].
+ // -4 352 callsubr # 352 + bias = 459
+ // : # Arg stack is [90 83 -4].
+ // : 51 210 51 return
+ // : # Arg stack is [90 83 -4 51 210 51].
+ // -3 84 hintmask 11111001
+ // 90 -40 callsubr # -40 + bias = 67
+ // : # Arg stack is [90].
+ // : -27 callgsubr # -27 + bias = 80
+ // : : # Arg stack is [90].
+ // : : hmoveto
+ moveTo(90, 0),
+ // : : 83 309 305 -309 84 return
+ // : : # Arg stack is [83 309 305 -309 84].
+ // : -41 callgsubr # -41 + bias = 66
+ // : : # Arg stack is [83 309 305 -309 84].
+ // : : 656 -84 -275 -305 275 -83 return
+ // : : # Arg stack is [83 309 305 -309 84 656 -84 -275 -305 275 -83].
+ // : hlineto
+ lineTo(173, 0),
+ lineTo(173, 309),
+ lineTo(478, 309),
+ lineTo(478, 0),
+ lineTo(562, 0),
+ lineTo(562, 656),
+ lineTo(478, 656),
+ lineTo(478, 381),
+ lineTo(173, 381),
+ lineTo(173, 656),
+ lineTo(90, 656),
+ // : return
+ // : # Arg stack is [].
+ // hintmask 11110110
+ // 235 -887 143 callsubr # 143 + bias = 250
+ // : # Arg stack is [235 -887].
+ // : rmoveto
+ moveTo(325, -231),
+ // : -84 callsubr # -84 + bias = 23
+ // : : # Arg stack is [].
+ // : : 107 44 77 74 5 hvcurveto
+ cubeTo(432, -231, 476, -154, 481, -80),
+ // : : -51 8 rlineto
+ lineTo(430, -72),
+ // : : -51 -8 -32 -53 -65 hhcurveto
+ cubeTo(422, -123, 390, -176, 325, -176),
+ // : : -65 -32 53 51 -8 hvcurveto
+ cubeTo(260, -176, 228, -123, 220, -72),
+ // : : -51 -22 callsubr # -22 + bias = 85
+ // : : : # Arg stack is [-51].
+ // : : : -8 rlineto
+ lineTo(169, -80),
+ // : : : -74 5 44 -77 107 hhcurveto
+ cubeTo(174, -154, 218, -231, 325, -231),
+ // : : : return
+ // : : : # Arg stack is [].
+ // : : return
+ // : : # Arg stack is [].
+ // : return
+ // : # Arg stack is [].
+ // endchar
+ },
},
"microsoft/Arial.ttf": {
