aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/pdf/SkPDFGraphicState.cpp
blob: 55f3b3929fea31b3d3434bc36cb413ef000ff182 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkData.h"
#include "SkLazyPtr.h"
#include "SkPDFCanon.h"
#include "SkPDFFormXObject.h"
#include "SkPDFGraphicState.h"
#include "SkPDFUtils.h"
#include "SkTypes.h"

static const char* as_blend_mode(SkXfermode::Mode mode) {
    switch (mode) {
        case SkXfermode::kSrcOver_Mode:
            return "Normal";
        case SkXfermode::kMultiply_Mode:
            return "Multiply";
        case SkXfermode::kScreen_Mode:
            return "Screen";
        case SkXfermode::kOverlay_Mode:
            return "Overlay";
        case SkXfermode::kDarken_Mode:
            return "Darken";
        case SkXfermode::kLighten_Mode:
            return "Lighten";
        case SkXfermode::kColorDodge_Mode:
            return "ColorDodge";
        case SkXfermode::kColorBurn_Mode:
            return "ColorBurn";
        case SkXfermode::kHardLight_Mode:
            return "HardLight";
        case SkXfermode::kSoftLight_Mode:
            return "SoftLight";
        case SkXfermode::kDifference_Mode:
            return "Difference";
        case SkXfermode::kExclusion_Mode:
            return "Exclusion";
        case SkXfermode::kHue_Mode:
            return "Hue";
        case SkXfermode::kSaturation_Mode:
            return "Saturation";
        case SkXfermode::kColor_Mode:
            return "Color";
        case SkXfermode::kLuminosity_Mode:
            return "Luminosity";

        // These are handled in SkPDFDevice::setUpContentEntry.
        case SkXfermode::kClear_Mode:
        case SkXfermode::kSrc_Mode:
        case SkXfermode::kDst_Mode:
        case SkXfermode::kDstOver_Mode:
        case SkXfermode::kSrcIn_Mode:
        case SkXfermode::kDstIn_Mode:
        case SkXfermode::kSrcOut_Mode:
        case SkXfermode::kDstOut_Mode:
        case SkXfermode::kSrcATop_Mode:
        case SkXfermode::kDstATop_Mode:
        case SkXfermode::kModulate_Mode:
            return "Normal";

        // TODO(vandebo): Figure out if we can support more of these modes.
        case SkXfermode::kXor_Mode:
        case SkXfermode::kPlus_Mode:
            return NULL;
    }
    return NULL;
}

// If a SkXfermode is unsupported in PDF, this function returns
// SrcOver, otherwise, it returns that Xfermode as a Mode.
static SkXfermode::Mode mode_for_pdf(const SkXfermode* xfermode) {
    SkXfermode::Mode mode = SkXfermode::kSrcOver_Mode;
    if (xfermode) {
        xfermode->asMode(&mode);
    }
    switch (mode) {
        case SkXfermode::kSrcOver_Mode:
        case SkXfermode::kMultiply_Mode:
        case SkXfermode::kScreen_Mode:
        case SkXfermode::kOverlay_Mode:
        case SkXfermode::kDarken_Mode:
        case SkXfermode::kLighten_Mode:
        case SkXfermode::kColorDodge_Mode:
        case SkXfermode::kColorBurn_Mode:
        case SkXfermode::kHardLight_Mode:
        case SkXfermode::kSoftLight_Mode:
        case SkXfermode::kDifference_Mode:
        case SkXfermode::kExclusion_Mode:
        case SkXfermode::kHue_Mode:
        case SkXfermode::kSaturation_Mode:
        case SkXfermode::kColor_Mode:
        case SkXfermode::kLuminosity_Mode:
            // Mode is suppported and handled by pdf graphics state.
            return mode;
        default:
            return SkXfermode::kSrcOver_Mode;  // Default mode.
    }
}

SkPDFGraphicState::SkPDFGraphicState(const SkPaint& p)
    : fStrokeWidth(p.getStrokeWidth())
    , fStrokeMiter(p.getStrokeMiter())
    , fAlpha(p.getAlpha())
    , fStrokeCap(SkToU8(p.getStrokeCap()))
    , fStrokeJoin(SkToU8(p.getStrokeJoin()))
    , fMode(SkToU8(mode_for_pdf(p.getXfermode()))) {}

// static
SkPDFGraphicState* SkPDFGraphicState::GetGraphicStateForPaint(
        SkPDFCanon* canon, const SkPaint& paint) {
    SkASSERT(canon);
    SkPDFGraphicState key(paint);
    if (const SkPDFGraphicState* canonGS = canon->findGraphicState(key)) {
        // The returned SkPDFGraphicState must be made non-const,
        // since the emitObject() interface is non-const.  But We
        // promise that there is no way to mutate this object from
        // here on out.
        return SkRef(const_cast<SkPDFGraphicState*>(canonGS));
    }
    SkPDFGraphicState* pdfGraphicState = new SkPDFGraphicState(paint);
    canon->addGraphicState(pdfGraphicState);
    return pdfGraphicState;
}

namespace {
SkPDFObject* create_invert_function() {
    // Acrobat crashes if we use a type 0 function, kpdf crashes if we use
    // a type 2 function, so we use a type 4 function.
    SkAutoTUnref<SkPDFArray> domainAndRange(new SkPDFArray);
    domainAndRange->reserve(2);
    domainAndRange->appendInt(0);
    domainAndRange->appendInt(1);

    static const char psInvert[] = "{1 exch sub}";
    // Do not copy the trailing '\0' into the SkData.
    SkAutoTUnref<SkData> psInvertStream(
            SkData::NewWithoutCopy(psInvert, strlen(psInvert)));

    SkPDFStream* invertFunction = SkNEW_ARGS(
            SkPDFStream, (psInvertStream.get()));
    invertFunction->insertInt("FunctionType", 4);
    invertFunction->insertObject("Domain", SkRef(domainAndRange.get()));
    invertFunction->insertObject("Range", domainAndRange.detach());
    return invertFunction;
}

template <typename T> void unref(T* ptr) { ptr->unref(); }
}  // namespace

SK_DECLARE_STATIC_LAZY_PTR(SkPDFObject,
                           invertFunction,
                           create_invert_function,
                           unref<SkPDFObject>);

// static
SkPDFDict* SkPDFGraphicState::GetSMaskGraphicState(SkPDFFormXObject* sMask,
                                                   bool invert,
                                                   SkPDFSMaskMode sMaskMode) {
    // The practical chances of using the same mask more than once are unlikely
    // enough that it's not worth canonicalizing.
    SkAutoTUnref<SkPDFDict> sMaskDict(new SkPDFDict("Mask"));
    if (sMaskMode == kAlpha_SMaskMode) {
        sMaskDict->insertName("S", "Alpha");
    } else if (sMaskMode == kLuminosity_SMaskMode) {
        sMaskDict->insertName("S", "Luminosity");
    }
    sMaskDict->insertObjRef("G", SkRef(sMask));
    if (invert) {
        sMaskDict->insertObjRef("TR", SkRef(invertFunction.get()));
    }

    SkPDFDict* result = new SkPDFDict("ExtGState");
    result->insertObject("SMask", sMaskDict.detach());
    return result;
}

namespace {
SkPDFDict* create_no_smask_graphic_state() {
    SkPDFDict* noSMaskGS = new SkPDFDict("ExtGState");
    noSMaskGS->insertName("SMask", "None");
    return noSMaskGS;
}
} // namespace
SK_DECLARE_STATIC_LAZY_PTR(SkPDFDict,
                           noSMaskGraphicState,
                           create_no_smask_graphic_state,
                           unref<SkPDFDict>);

// static
SkPDFDict* SkPDFGraphicState::GetNoSMaskGraphicState() {
    return SkRef(noSMaskGraphicState.get());
}

void SkPDFGraphicState::emitObject(
        SkWStream* stream,
        const SkPDFObjNumMap& objNumMap,
        const SkPDFSubstituteMap& substitutes) const {
    SkAutoTUnref<SkPDFDict> dict(SkNEW_ARGS(SkPDFDict, ("ExtGState")));
    dict->insertName("Type", "ExtGState");

    SkScalar alpha = SkIntToScalar(fAlpha) / 0xFF;
    dict->insertScalar("CA", alpha);
    dict->insertScalar("ca", alpha);

    SkPaint::Cap strokeCap = (SkPaint::Cap)fStrokeCap;
    SkPaint::Join strokeJoin = (SkPaint::Join)fStrokeJoin;
    SkXfermode::Mode xferMode = (SkXfermode::Mode)fMode;

    SK_COMPILE_ASSERT(SkPaint::kButt_Cap == 0, paint_cap_mismatch);
    SK_COMPILE_ASSERT(SkPaint::kRound_Cap == 1, paint_cap_mismatch);
    SK_COMPILE_ASSERT(SkPaint::kSquare_Cap == 2, paint_cap_mismatch);
    SK_COMPILE_ASSERT(SkPaint::kCapCount == 3, paint_cap_mismatch);
    SkASSERT(strokeCap >= 0 && strokeCap <= 2);
    dict->insertInt("LC", strokeCap);

    SK_COMPILE_ASSERT(SkPaint::kMiter_Join == 0, paint_join_mismatch);
    SK_COMPILE_ASSERT(SkPaint::kRound_Join == 1, paint_join_mismatch);
    SK_COMPILE_ASSERT(SkPaint::kBevel_Join == 2, paint_join_mismatch);
    SK_COMPILE_ASSERT(SkPaint::kJoinCount == 3, paint_join_mismatch);
    SkASSERT(strokeJoin >= 0 && strokeJoin <= 2);
    dict->insertInt("LJ", strokeJoin);

    dict->insertScalar("LW", fStrokeWidth);
    dict->insertScalar("ML", fStrokeMiter);
    dict->insertBool("SA", true);  // SA = Auto stroke adjustment.
    dict->insertName("BM", as_blend_mode(xferMode));
    dict->emitObject(stream, objNumMap, substitutes);
}