1 /*
2 * Copyright 2011 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SkData.h"
9 #include "SkPaint.h"
10 #include "SkPDFCanon.h"
11 #include "SkPDFFormXObject.h"
12 #include "SkPDFGraphicState.h"
13 #include "SkPDFUtils.h"
14
as_blend_mode(SkBlendMode mode)15 static const char* as_blend_mode(SkBlendMode mode) {
16 switch (mode) {
17 case SkBlendMode::kSrcOver:
18 return "Normal";
19 case SkBlendMode::kMultiply:
20 return "Multiply";
21 case SkBlendMode::kScreen:
22 return "Screen";
23 case SkBlendMode::kOverlay:
24 return "Overlay";
25 case SkBlendMode::kDarken:
26 return "Darken";
27 case SkBlendMode::kLighten:
28 return "Lighten";
29 case SkBlendMode::kColorDodge:
30 return "ColorDodge";
31 case SkBlendMode::kColorBurn:
32 return "ColorBurn";
33 case SkBlendMode::kHardLight:
34 return "HardLight";
35 case SkBlendMode::kSoftLight:
36 return "SoftLight";
37 case SkBlendMode::kDifference:
38 return "Difference";
39 case SkBlendMode::kExclusion:
40 return "Exclusion";
41 case SkBlendMode::kHue:
42 return "Hue";
43 case SkBlendMode::kSaturation:
44 return "Saturation";
45 case SkBlendMode::kColor:
46 return "Color";
47 case SkBlendMode::kLuminosity:
48 return "Luminosity";
49
50 // These are handled in SkPDFDevice::setUpContentEntry.
51 case SkBlendMode::kClear:
52 case SkBlendMode::kSrc:
53 case SkBlendMode::kDst:
54 case SkBlendMode::kDstOver:
55 case SkBlendMode::kSrcIn:
56 case SkBlendMode::kDstIn:
57 case SkBlendMode::kSrcOut:
58 case SkBlendMode::kDstOut:
59 case SkBlendMode::kSrcATop:
60 case SkBlendMode::kDstATop:
61 case SkBlendMode::kModulate:
62 return "Normal";
63
64 // TODO(vandebo): Figure out if we can support more of these modes.
65 case SkBlendMode::kXor:
66 case SkBlendMode::kPlus:
67 return nullptr;
68 }
69 return nullptr;
70 }
71
72 // If a SkXfermode is unsupported in PDF, this function returns
73 // SrcOver, otherwise, it returns that Xfermode as a Mode.
mode_for_pdf(SkBlendMode mode)74 static SkBlendMode mode_for_pdf(SkBlendMode mode) {
75 switch (mode) {
76 case SkBlendMode::kSrcOver:
77 case SkBlendMode::kMultiply:
78 case SkBlendMode::kScreen:
79 case SkBlendMode::kOverlay:
80 case SkBlendMode::kDarken:
81 case SkBlendMode::kLighten:
82 case SkBlendMode::kColorDodge:
83 case SkBlendMode::kColorBurn:
84 case SkBlendMode::kHardLight:
85 case SkBlendMode::kSoftLight:
86 case SkBlendMode::kDifference:
87 case SkBlendMode::kExclusion:
88 case SkBlendMode::kHue:
89 case SkBlendMode::kSaturation:
90 case SkBlendMode::kColor:
91 case SkBlendMode::kLuminosity:
92 // Mode is suppported and handled by pdf graphics state.
93 return mode;
94 default:
95 return SkBlendMode::kSrcOver; // Default mode.
96 }
97 }
98
SkPDFGraphicState(const SkPaint & p)99 SkPDFGraphicState::SkPDFGraphicState(const SkPaint& p)
100 : fStrokeWidth(p.getStrokeWidth())
101 , fStrokeMiter(p.getStrokeMiter())
102 , fAlpha(p.getAlpha())
103 , fStrokeCap(SkToU8(p.getStrokeCap()))
104 , fStrokeJoin(SkToU8(p.getStrokeJoin()))
105 , fMode(SkToU8((unsigned)mode_for_pdf(p.getBlendMode()))) {}
106
107 // static
GetGraphicStateForPaint(SkPDFCanon * canon,const SkPaint & paint)108 SkPDFGraphicState* SkPDFGraphicState::GetGraphicStateForPaint(
109 SkPDFCanon* canon, const SkPaint& paint) {
110 SkASSERT(canon);
111 SkPDFGraphicState key(paint);
112 if (const SkPDFGraphicState* canonGS = canon->findGraphicState(key)) {
113 // The returned SkPDFGraphicState must be made non-const,
114 // since the emitObject() interface is non-const. But We
115 // promise that there is no way to mutate this object from
116 // here on out.
117 return SkRef(const_cast<SkPDFGraphicState*>(canonGS));
118 }
119 SkPDFGraphicState* pdfGraphicState = new SkPDFGraphicState(paint);
120 canon->addGraphicState(pdfGraphicState);
121 return pdfGraphicState;
122 }
123
MakeInvertFunction()124 sk_sp<SkPDFStream> SkPDFGraphicState::MakeInvertFunction() {
125 // Acrobat crashes if we use a type 0 function, kpdf crashes if we use
126 // a type 2 function, so we use a type 4 function.
127 auto domainAndRange = sk_make_sp<SkPDFArray>();
128 domainAndRange->reserve(2);
129 domainAndRange->appendInt(0);
130 domainAndRange->appendInt(1);
131
132 static const char psInvert[] = "{1 exch sub}";
133 // Do not copy the trailing '\0' into the SkData.
134 auto invertFunction = sk_make_sp<SkPDFStream>(
135 SkData::MakeWithoutCopy(psInvert, strlen(psInvert)));
136 invertFunction->dict()->insertInt("FunctionType", 4);
137 invertFunction->dict()->insertObject("Domain", domainAndRange);
138 invertFunction->dict()->insertObject("Range", std::move(domainAndRange));
139 return invertFunction;
140 }
141
GetSMaskGraphicState(sk_sp<SkPDFObject> sMask,bool invert,SkPDFSMaskMode sMaskMode,SkPDFCanon * canon)142 sk_sp<SkPDFDict> SkPDFGraphicState::GetSMaskGraphicState(
143 sk_sp<SkPDFObject> sMask,
144 bool invert,
145 SkPDFSMaskMode sMaskMode,
146 SkPDFCanon* canon) {
147 // The practical chances of using the same mask more than once are unlikely
148 // enough that it's not worth canonicalizing.
149 auto sMaskDict = sk_make_sp<SkPDFDict>("Mask");
150 if (sMaskMode == kAlpha_SMaskMode) {
151 sMaskDict->insertName("S", "Alpha");
152 } else if (sMaskMode == kLuminosity_SMaskMode) {
153 sMaskDict->insertName("S", "Luminosity");
154 }
155 sMaskDict->insertObjRef("G", std::move(sMask));
156 if (invert) {
157 // Instead of calling SkPDFGraphicState::MakeInvertFunction,
158 // let the canon deduplicate this object.
159 sMaskDict->insertObjRef("TR", canon->makeInvertFunction());
160 }
161
162 auto result = sk_make_sp<SkPDFDict>("ExtGState");
163 result->insertObject("SMask", std::move(sMaskDict));
164 return result;
165 }
166
MakeNoSmaskGraphicState()167 sk_sp<SkPDFDict> SkPDFGraphicState::MakeNoSmaskGraphicState() {
168 auto noSMaskGS = sk_make_sp<SkPDFDict>("ExtGState");
169 noSMaskGS->insertName("SMask", "None");
170 return noSMaskGS;
171 }
172
emitObject(SkWStream * stream,const SkPDFObjNumMap & objNumMap) const173 void SkPDFGraphicState::emitObject(
174 SkWStream* stream,
175 const SkPDFObjNumMap& objNumMap) const {
176 auto dict = sk_make_sp<SkPDFDict>("ExtGState");
177 dict->insertName("Type", "ExtGState");
178
179 SkScalar alpha = SkIntToScalar(fAlpha) / 0xFF;
180 dict->insertScalar("CA", alpha);
181 dict->insertScalar("ca", alpha);
182
183 SkPaint::Cap strokeCap = (SkPaint::Cap)fStrokeCap;
184 SkPaint::Join strokeJoin = (SkPaint::Join)fStrokeJoin;
185
186 static_assert(SkPaint::kButt_Cap == 0, "paint_cap_mismatch");
187 static_assert(SkPaint::kRound_Cap == 1, "paint_cap_mismatch");
188 static_assert(SkPaint::kSquare_Cap == 2, "paint_cap_mismatch");
189 static_assert(SkPaint::kCapCount == 3, "paint_cap_mismatch");
190 SkASSERT(strokeCap >= 0 && strokeCap <= 2);
191 dict->insertInt("LC", strokeCap);
192
193 static_assert(SkPaint::kMiter_Join == 0, "paint_join_mismatch");
194 static_assert(SkPaint::kRound_Join == 1, "paint_join_mismatch");
195 static_assert(SkPaint::kBevel_Join == 2, "paint_join_mismatch");
196 static_assert(SkPaint::kJoinCount == 3, "paint_join_mismatch");
197 SkASSERT(strokeJoin >= 0 && strokeJoin <= 2);
198 dict->insertInt("LJ", strokeJoin);
199
200 dict->insertScalar("LW", fStrokeWidth);
201 dict->insertScalar("ML", fStrokeMiter);
202 dict->insertBool("SA", true); // SA = Auto stroke adjustment.
203 dict->insertName("BM", as_blend_mode((SkBlendMode)fMode));
204 dict->emitObject(stream, objNumMap);
205 }
206