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 "src/pdf/SkPDFGraphicState.h"
9
10 #include "include/core/SkBlendMode.h"
11 #include "include/core/SkColor.h"
12 #include "include/core/SkData.h"
13 #include "include/core/SkPaint.h"
14 #include "include/core/SkStream.h"
15 #include "include/private/base/SkAssert.h"
16 #include "include/private/base/SkTo.h"
17 #include "src/core/SkTHash.h"
18 #include "src/pdf/SkPDFDocumentPriv.h"
19 #include "src/pdf/SkPDFUtils.h"
20
21 #include <memory>
22 #include <utility>
23
as_pdf_blend_mode_name(SkBlendMode mode)24 static const char* as_pdf_blend_mode_name(SkBlendMode mode) {
25 const char* name = SkPDFUtils::BlendModeName(mode);
26 SkASSERT(name);
27 return name;
28 }
29
to_stroke_cap(uint8_t cap)30 static int to_stroke_cap(uint8_t cap) {
31 // PDF32000.book section 8.4.3.3 "Line Cap Style"
32 switch ((SkPaint::Cap)cap) {
33 case SkPaint::kButt_Cap: return 0;
34 case SkPaint::kRound_Cap: return 1;
35 case SkPaint::kSquare_Cap: return 2;
36 default: SkASSERT(false); return 0;
37 }
38 }
39
to_stroke_join(uint8_t join)40 static int to_stroke_join(uint8_t join) {
41 // PDF32000.book section 8.4.3.4 "Line Join Style"
42 switch ((SkPaint::Join)join) {
43 case SkPaint::kMiter_Join: return 0;
44 case SkPaint::kRound_Join: return 1;
45 case SkPaint::kBevel_Join: return 2;
46 default: SkASSERT(false); return 0;
47 }
48 }
49
50 // If a SkBlendMode is unsupported in PDF, this function returns
51 // SrcOver, otherwise, it returns the blend mode.
pdf_blend_mode(SkBlendMode mode)52 static uint8_t pdf_blend_mode(SkBlendMode mode) {
53 if (!SkPDFUtils::BlendModeName(mode)
54 || SkBlendMode::kXor == mode
55 || SkBlendMode::kPlus == mode)
56 {
57 mode = SkBlendMode::kSrcOver;
58 }
59 return SkToU8((unsigned)mode);
60 }
61
GetGraphicStateForPaint(SkPDFDocument * doc,const SkPaint & p)62 SkPDFIndirectReference SkPDFGraphicState::GetGraphicStateForPaint(SkPDFDocument* doc,
63 const SkPaint& p) {
64 SkASSERT(doc);
65 const SkBlendMode mode = p.getBlendMode_or(SkBlendMode::kSrcOver);
66
67 if (SkPaint::kFill_Style == p.getStyle()) {
68 SkPDFFillGraphicState fillKey = {p.getColor4f().fA, pdf_blend_mode(mode)};
69 auto& fillMap = doc->fFillGSMap;
70 if (SkPDFIndirectReference* statePtr = fillMap.find(fillKey)) {
71 return *statePtr;
72 }
73 SkPDFDict state;
74 state.reserve(2);
75 state.insertColorComponentF("ca", fillKey.fAlpha);
76 state.insertName("BM", as_pdf_blend_mode_name((SkBlendMode)fillKey.fBlendMode));
77 SkPDFIndirectReference ref = doc->emit(state);
78 fillMap.set(fillKey, ref);
79 return ref;
80 } else {
81 SkPDFStrokeGraphicState strokeKey = {
82 p.getStrokeWidth(),
83 p.getStrokeMiter(),
84 p.getColor4f().fA,
85 SkToU8(p.getStrokeCap()),
86 SkToU8(p.getStrokeJoin()),
87 pdf_blend_mode(mode)
88 };
89 auto& sMap = doc->fStrokeGSMap;
90 if (SkPDFIndirectReference* statePtr = sMap.find(strokeKey)) {
91 return *statePtr;
92 }
93 SkPDFDict state;
94 state.reserve(8);
95 state.insertColorComponentF("CA", strokeKey.fAlpha);
96 state.insertColorComponentF("ca", strokeKey.fAlpha);
97 state.insertInt("LC", to_stroke_cap(strokeKey.fStrokeCap));
98 state.insertInt("LJ", to_stroke_join(strokeKey.fStrokeJoin));
99 state.insertScalar("LW", strokeKey.fStrokeWidth);
100 state.insertScalar("ML", strokeKey.fStrokeMiter);
101 state.insertBool("SA", true); // SA = Auto stroke adjustment.
102 state.insertName("BM", as_pdf_blend_mode_name((SkBlendMode)strokeKey.fBlendMode));
103 SkPDFIndirectReference ref = doc->emit(state);
104 sMap.set(strokeKey, ref);
105 return ref;
106 }
107 }
108
109 ////////////////////////////////////////////////////////////////////////////////
110
make_invert_function(SkPDFDocument * doc)111 static SkPDFIndirectReference make_invert_function(SkPDFDocument* doc) {
112 // Acrobat crashes if we use a type 0 function, kpdf crashes if we use
113 // a type 2 function, so we use a type 4 function.
114 static const char psInvert[] = "{1 exch sub}";
115 // Do not copy the trailing '\0' into the SkData.
116 auto invertFunction = SkData::MakeWithoutCopy(psInvert, strlen(psInvert));
117
118 std::unique_ptr<SkPDFDict> dict = SkPDFMakeDict();
119 dict->insertInt("FunctionType", 4);
120 dict->insertObject("Domain", SkPDFMakeArray(0, 1));
121 dict->insertObject("Range", SkPDFMakeArray(0, 1));
122 return SkPDFStreamOut(std::move(dict), SkMemoryStream::Make(std::move(invertFunction)), doc);
123 }
124
GetSMaskGraphicState(SkPDFIndirectReference sMask,bool invert,SkPDFSMaskMode sMaskMode,SkPDFDocument * doc)125 SkPDFIndirectReference SkPDFGraphicState::GetSMaskGraphicState(SkPDFIndirectReference sMask,
126 bool invert,
127 SkPDFSMaskMode sMaskMode,
128 SkPDFDocument* doc) {
129 // The practical chances of using the same mask more than once are unlikely
130 // enough that it's not worth canonicalizing.
131 auto sMaskDict = SkPDFMakeDict("Mask");
132 if (sMaskMode == kAlpha_SMaskMode) {
133 sMaskDict->insertName("S", "Alpha");
134 } else if (sMaskMode == kLuminosity_SMaskMode) {
135 sMaskDict->insertName("S", "Luminosity");
136 }
137 sMaskDict->insertRef("G", sMask);
138 if (invert) {
139 // let the doc deduplicate this object.
140 if (doc->fInvertFunction == SkPDFIndirectReference()) {
141 doc->fInvertFunction = make_invert_function(doc);
142 }
143 sMaskDict->insertRef("TR", doc->fInvertFunction);
144 }
145 SkPDFDict result("ExtGState");
146 result.insertObject("SMask", std::move(sMaskDict));
147 return doc->emit(result);
148 }
149