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* 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 "SkPaint.h"
#include "SkPDFCanon.h"
#include "SkPDFFormXObject.h"
#include "SkPDFGraphicState.h"
#include "SkPDFUtils.h"
static const char* as_blend_mode(SkBlendMode mode) {
switch (mode) {
case SkBlendMode::kSrcOver:
return "Normal";
case SkBlendMode::kMultiply:
return "Multiply";
case SkBlendMode::kScreen:
return "Screen";
case SkBlendMode::kOverlay:
return "Overlay";
case SkBlendMode::kDarken:
return "Darken";
case SkBlendMode::kLighten:
return "Lighten";
case SkBlendMode::kColorDodge:
return "ColorDodge";
case SkBlendMode::kColorBurn:
return "ColorBurn";
case SkBlendMode::kHardLight:
return "HardLight";
case SkBlendMode::kSoftLight:
return "SoftLight";
case SkBlendMode::kDifference:
return "Difference";
case SkBlendMode::kExclusion:
return "Exclusion";
case SkBlendMode::kHue:
return "Hue";
case SkBlendMode::kSaturation:
return "Saturation";
case SkBlendMode::kColor:
return "Color";
case SkBlendMode::kLuminosity:
return "Luminosity";
// These are handled in SkPDFDevice::setUpContentEntry.
case SkBlendMode::kClear:
case SkBlendMode::kSrc:
case SkBlendMode::kDst:
case SkBlendMode::kDstOver:
case SkBlendMode::kSrcIn:
case SkBlendMode::kDstIn:
case SkBlendMode::kSrcOut:
case SkBlendMode::kDstOut:
case SkBlendMode::kSrcATop:
case SkBlendMode::kDstATop:
case SkBlendMode::kModulate:
return "Normal";
// TODO(vandebo): Figure out if we can support more of these modes.
case SkBlendMode::kXor:
case SkBlendMode::kPlus:
return nullptr;
return nullptr;
// If a SkXfermode is unsupported in PDF, this function returns
// SrcOver, otherwise, it returns that Xfermode as a Mode.
static SkBlendMode mode_for_pdf(SkBlendMode mode) {
switch (mode) {
case SkBlendMode::kSrcOver:
case SkBlendMode::kMultiply:
case SkBlendMode::kScreen:
case SkBlendMode::kOverlay:
case SkBlendMode::kDarken:
case SkBlendMode::kLighten:
case SkBlendMode::kColorDodge:
case SkBlendMode::kColorBurn:
case SkBlendMode::kHardLight:
case SkBlendMode::kSoftLight:
case SkBlendMode::kDifference:
case SkBlendMode::kExclusion:
case SkBlendMode::kHue:
case SkBlendMode::kSaturation:
case SkBlendMode::kColor:
case SkBlendMode::kLuminosity:
// Mode is suppported and handled by pdf graphics state.
return mode;
return SkBlendMode::kSrcOver; // 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((unsigned)mode_for_pdf(p.getBlendMode()))) {}
// static
SkPDFGraphicState* SkPDFGraphicState::GetGraphicStateForPaint(
SkPDFCanon* canon, const SkPaint& paint) {
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);
return pdfGraphicState;
sk_sp<SkPDFStream> SkPDFGraphicState::MakeInvertFunction() {
// 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.
auto domainAndRange = sk_make_sp<SkPDFArray>();
static const char psInvert[] = "{1 exch sub}";
// Do not copy the trailing '\0' into the SkData.
auto invertFunction = sk_make_sp<SkPDFStream>(
SkData::MakeWithoutCopy(psInvert, strlen(psInvert)));
invertFunction->dict()->insertInt("FunctionType", 4);
invertFunction->dict()->insertObject("Domain", domainAndRange);
invertFunction->dict()->insertObject("Range", std::move(domainAndRange));
return invertFunction;
sk_sp<SkPDFDict> SkPDFGraphicState::GetSMaskGraphicState(
sk_sp<SkPDFObject> sMask,
bool invert,
SkPDFSMaskMode sMaskMode,
SkPDFCanon* canon) {
// The practical chances of using the same mask more than once are unlikely
// enough that it's not worth canonicalizing.
auto sMaskDict = sk_make_sp<SkPDFDict>("Mask");
if (sMaskMode == kAlpha_SMaskMode) {
sMaskDict->insertName("S", "Alpha");
} else if (sMaskMode == kLuminosity_SMaskMode) {
sMaskDict->insertName("S", "Luminosity");
sMaskDict->insertObjRef("G", std::move(sMask));
if (invert) {
// Instead of calling SkPDFGraphicState::MakeInvertFunction,
// let the canon deduplicate this object.
sMaskDict->insertObjRef("TR", canon->makeInvertFunction());
auto result = sk_make_sp<SkPDFDict>("ExtGState");
result->insertObject("SMask", std::move(sMaskDict));
return result;
sk_sp<SkPDFDict> SkPDFGraphicState::MakeNoSmaskGraphicState() {
auto noSMaskGS = sk_make_sp<SkPDFDict>("ExtGState");
noSMaskGS->insertName("SMask", "None");
return noSMaskGS;
void SkPDFGraphicState::emitObject(
SkWStream* stream,
const SkPDFObjNumMap& objNumMap) const {
auto dict = sk_make_sp<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;
static_assert(SkPaint::kButt_Cap == 0, "paint_cap_mismatch");
static_assert(SkPaint::kRound_Cap == 1, "paint_cap_mismatch");
static_assert(SkPaint::kSquare_Cap == 2, "paint_cap_mismatch");
static_assert(SkPaint::kCapCount == 3, "paint_cap_mismatch");
SkASSERT(strokeCap >= 0 && strokeCap <= 2);
dict->insertInt("LC", strokeCap);
static_assert(SkPaint::kMiter_Join == 0, "paint_join_mismatch");
static_assert(SkPaint::kRound_Join == 1, "paint_join_mismatch");
static_assert(SkPaint::kBevel_Join == 2, "paint_join_mismatch");
static_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((SkBlendMode)fMode));
dict->emitObject(stream, objNumMap);