/*
* 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 "SkDocument.h"
#include "SkPDFCanon.h"
#include "SkPDFDevice.h"
#include "SkPDFFont.h"
#include "SkPDFStream.h"
#include "SkPDFTypes.h"
#include "SkStream.h"
static void emit_pdf_header(SkWStream* stream) {
stream->writeText("%PDF-1.4\n%");
// The PDF spec recommends including a comment with four bytes, all
// with their high bits set. This is "Skia" with the high bits set.
stream->write32(0xD3EBE9E1);
stream->writeText("\n");
}
static void emit_pdf_footer(SkWStream* stream,
const SkPDFObjNumMap& objNumMap,
const SkPDFSubstituteMap& substitutes,
SkPDFObject* docCatalog,
int64_t objCount,
int32_t xRefFileOffset) {
SkPDFDict trailerDict;
// TODO(vandebo): Linearized format will take a Prev entry too.
// TODO(vandebo): PDF/A requires an ID entry.
trailerDict.insertInt("Size", int(objCount));
trailerDict.insertObjRef("Root", SkRef(docCatalog));
stream->writeText("trailer\n");
trailerDict.emitObject(stream, objNumMap, substitutes);
stream->writeText("\nstartxref\n");
stream->writeBigDecAsText(xRefFileOffset);
stream->writeText("\n%%EOF");
}
static void perform_font_subsetting(
const SkTDArray<const SkPDFDevice*>& pageDevices,
SkPDFSubstituteMap* substituteMap) {
SkASSERT(substituteMap);
SkPDFGlyphSetMap usage;
for (int i = 0; i < pageDevices.count(); ++i) {
usage.merge(pageDevices[i]->getFontGlyphUsage());
}
SkPDFGlyphSetMap::F2BIter iterator(usage);
const SkPDFGlyphSetMap::FontGlyphSetPair* entry = iterator.next();
while (entry) {
SkAutoTUnref<SkPDFFont> subsetFont(
entry->fFont->getFontSubset(entry->fGlyphSet));
if (subsetFont) {
substituteMap->setSubstitute(entry->fFont, subsetFont.get());
}
entry = iterator.next();
}
}
static SkPDFObject* create_pdf_page_content(const SkPDFDevice* pageDevice) {
SkAutoTDelete<SkStreamAsset> content(pageDevice->content());
return SkNEW_ARGS(SkPDFStream, (content.get()));
}
static SkPDFDict* create_pdf_page(const SkPDFDevice* pageDevice) {
SkAutoTUnref<SkPDFDict> page(SkNEW_ARGS(SkPDFDict, ("Page")));
page->insertObject("Resources", pageDevice->createResourceDict());
page->insertObject("MediaBox", pageDevice->copyMediaBox());
if (SkPDFArray* annots = pageDevice->getAnnotations()) {
SkASSERT(annots->size() > 0);
page->insertObject("Annots", SkRef(annots));
}
page->insertObjRef("Contents", create_pdf_page_content(pageDevice));
return page.detach();
}
static void generate_page_tree(const SkTDArray<SkPDFDict*>& pages,
SkTDArray<SkPDFDict*>* pageTree,
SkPDFDict** rootNode) {
// PDF wants a tree describing all the pages in the document. We arbitrary
// choose 8 (kNodeSize) as the number of allowed children. The internal
// nodes have type "Pages" with an array of children, a parent pointer, and
// the number of leaves below the node as "Count." The leaves are passed
// into the method, have type "Page" and need a parent pointer. This method
// builds the tree bottom up, skipping internal nodes that would have only
// one child.
static const int kNodeSize = 8;
// curNodes takes a reference to its items, which it passes to pageTree.
SkTDArray<SkPDFDict*> curNodes;
curNodes.setReserve(pages.count());
for (int i = 0; i < pages.count(); i++) {
SkSafeRef(pages[i]);
curNodes.push(pages[i]);
}
// nextRoundNodes passes its references to nodes on to curNodes.
SkTDArray<SkPDFDict*> nextRoundNodes;
nextRoundNodes.setReserve((pages.count() + kNodeSize - 1)/kNodeSize);
int treeCapacity = kNodeSize;
do {
for (int i = 0; i < curNodes.count(); ) {
if (i > 0 && i + 1 == curNodes.count()) {
nextRoundNodes.push(curNodes[i]);
break;
}
SkAutoTUnref<SkPDFDict> newNode(new SkPDFDict("Pages"));
SkAutoTUnref<SkPDFArray> kids(new SkPDFArray);
kids->reserve(kNodeSize);
int count = 0;
for (; i < curNodes.count() && count < kNodeSize; i++, count++) {
curNodes[i]->insertObjRef("Parent", SkRef(newNode.get()));
kids->appendObjRef(SkRef(curNodes[i]));
// TODO(vandebo): put the objects in strict access order.
// Probably doesn't matter because they are so small.
if (curNodes[i] != pages[0]) {
pageTree->push(curNodes[i]); // Transfer reference.
} else {
SkSafeUnref(curNodes[i]);
}
}
// treeCapacity is the number of leaf nodes possible for the
// current set of subtrees being generated. (i.e. 8, 64, 512, ...).
// It is hard to count the number of leaf nodes in the current
// subtree. However, by construction, we know that unless it's the
// last subtree for the current depth, the leaf count will be
// treeCapacity, otherwise it's what ever is left over after
// consuming treeCapacity chunks.
int pageCount = treeCapacity;
if (i == curNodes.count()) {
pageCount = ((pages.count() - 1) % treeCapacity) + 1;
}
newNode->insertInt("Count", pageCount);
newNode->insertObject("Kids", kids.detach());
nextRoundNodes.push(newNode.detach()); // Transfer reference.
}
curNodes = nextRoundNodes;
nextRoundNodes.rewind();
treeCapacity *= kNodeSize;
} while (curNodes.count() > 1);
pageTree->push(curNodes[0]); // Transfer reference.
if (rootNode) {
*rootNode = curNodes[0];
}
}
static bool emit_pdf_document(const SkTDArray<const SkPDFDevice*>& pageDevices,
SkWStream* stream) {
if (pageDevices.isEmpty()) {
return false;
}
SkTDArray<SkPDFDict*> pages;
SkAutoTUnref<SkPDFDict> dests(SkNEW(SkPDFDict));
for (int i = 0; i < pageDevices.count(); i++) {
SkASSERT(pageDevices[i]);
SkASSERT(i == 0 ||
pageDevices[i - 1]->getCanon() == pageDevices[i]->getCanon());
SkAutoTUnref<SkPDFDict> page(create_pdf_page(pageDevices[i]));
pageDevices[i]->appendDestinations(dests, page.get());
pages.push(page.detach());
}
SkTDArray<SkPDFDict*> pageTree;
SkAutoTUnref<SkPDFDict> docCatalog(SkNEW_ARGS(SkPDFDict, ("Catalog")));
SkPDFDict* pageTreeRoot;
generate_page_tree(pages, &pageTree, &pageTreeRoot);
docCatalog->insertObjRef("Pages", SkRef(pageTreeRoot));
if (dests->size() > 0) {
docCatalog->insertObjRef("Dests", dests.detach());
}
/* TODO(vandebo): output intent
SkAutoTUnref<SkPDFDict> outputIntent = new SkPDFDict("OutputIntent");
outputIntent->insertName("S", "GTS_PDFA1");
outputIntent->insertString("OutputConditionIdentifier", "sRGB");
SkAutoTUnref<SkPDFArray> intentArray(new SkPDFArray);
intentArray->appendObject(SkRef(outputIntent.get()));
docCatalog->insertObject("OutputIntent", intentArray.detach());
*/
// Build font subsetting info before proceeding.
SkPDFSubstituteMap substitutes;
perform_font_subsetting(pageDevices, &substitutes);
SkPDFObjNumMap objNumMap;
if (objNumMap.addObject(docCatalog.get())) {
docCatalog->addResources(&objNumMap, substitutes);
}
size_t baseOffset = SkToOffT(stream->bytesWritten());
emit_pdf_header(stream);
SkTDArray<int32_t> offsets;
for (int i = 0; i < objNumMap.objects().count(); ++i) {
SkPDFObject* object = objNumMap.objects()[i];
offsets.push(SkToS32(stream->bytesWritten() - baseOffset));
SkASSERT(object == substitutes.getSubstitute(object));
SkASSERT(objNumMap.getObjectNumber(object) == i + 1);
stream->writeDecAsText(i + 1);
stream->writeText(" 0 obj\n"); // Generation number is always 0.
object->emitObject(stream, objNumMap, substitutes);
stream->writeText("\nendobj\n");
}
int32_t xRefFileOffset = SkToS32(stream->bytesWritten() - baseOffset);
// Include the zeroth object in the count.
int32_t objCount = SkToS32(offsets.count() + 1);
stream->writeText("xref\n0 ");
stream->writeDecAsText(objCount);
stream->writeText("\n0000000000 65535 f \n");
for (int i = 0; i < offsets.count(); i++) {
SkASSERT(offsets[i] > 0);
stream->writeBigDecAsText(offsets[i], 10);
stream->writeText(" 00000 n \n");
}
emit_pdf_footer(stream, objNumMap, substitutes, docCatalog.get(), objCount,
xRefFileOffset);
// The page tree has both child and parent pointers, so it creates a
// reference cycle. We must clear that cycle to properly reclaim memory.
for (int i = 0; i < pageTree.count(); i++) {
pageTree[i]->clear();
}
pageTree.safeUnrefAll();
pages.unrefAll();
return true;
}
#if 0
// TODO(halcanary): expose notEmbeddableCount in SkDocument
void GetCountOfFontTypes(
const SkTDArray<SkPDFDevice*>& pageDevices,
int counts[SkAdvancedTypefaceMetrics::kOther_Font + 1],
int* notSubsettableCount,
int* notEmbeddableCount) {
sk_bzero(counts, sizeof(int) *
(SkAdvancedTypefaceMetrics::kOther_Font + 1));
SkTDArray<SkFontID> seenFonts;
int notSubsettable = 0;
int notEmbeddable = 0;
for (int pageNumber = 0; pageNumber < pageDevices.count(); pageNumber++) {
const SkTDArray<SkPDFFont*>& fontResources =
pageDevices[pageNumber]->getFontResources();
for (int font = 0; font < fontResources.count(); font++) {
SkFontID fontID = fontResources[font]->typeface()->uniqueID();
if (seenFonts.find(fontID) == -1) {
counts[fontResources[font]->getType()]++;
seenFonts.push(fontID);
if (!fontResources[font]->canSubset()) {
notSubsettable++;
}
if (!fontResources[font]->canEmbed()) {
notEmbeddable++;
}
}
}
}
if (notSubsettableCount) {
*notSubsettableCount = notSubsettable;
}
if (notEmbeddableCount) {
*notEmbeddableCount = notEmbeddable;
}
}
#endif
////////////////////////////////////////////////////////////////////////////////
namespace {
class SkDocument_PDF : public SkDocument {
public:
SkDocument_PDF(SkWStream* stream,
void (*doneProc)(SkWStream*, bool),
SkScalar rasterDpi)
: SkDocument(stream, doneProc)
, fRasterDpi(rasterDpi) {}
virtual ~SkDocument_PDF() {
// subclasses must call close() in their destructors
this->close();
}
protected:
SkCanvas* onBeginPage(SkScalar width, SkScalar height,
const SkRect& trimBox) override {
SkASSERT(!fCanvas.get());
SkISize pageSize = SkISize::Make(
SkScalarRoundToInt(width), SkScalarRoundToInt(height));
SkAutoTUnref<SkPDFDevice> device(
SkPDFDevice::Create(pageSize, fRasterDpi, &fCanon));
fCanvas.reset(SkNEW_ARGS(SkCanvas, (device.get())));
fPageDevices.push(device.detach());
fCanvas->clipRect(trimBox);
fCanvas->translate(trimBox.x(), trimBox.y());
return fCanvas.get();
}
void onEndPage() override {
SkASSERT(fCanvas.get());
fCanvas->flush();
fCanvas.reset(NULL);
}
bool onClose(SkWStream* stream) override {
SkASSERT(!fCanvas.get());
bool success = emit_pdf_document(fPageDevices, stream);
fPageDevices.unrefAll();
fCanon.reset();
return success;
}
void onAbort() override {
fPageDevices.unrefAll();
fCanon.reset();
}
private:
SkPDFCanon fCanon;
SkTDArray<const SkPDFDevice*> fPageDevices;
SkAutoTUnref<SkCanvas> fCanvas;
SkScalar fRasterDpi;
};
} // namespace
///////////////////////////////////////////////////////////////////////////////
SkDocument* SkDocument::CreatePDF(SkWStream* stream, SkScalar dpi) {
return stream ? SkNEW_ARGS(SkDocument_PDF, (stream, NULL, dpi)) : NULL;
}
SkDocument* SkDocument::CreatePDF(const char path[], SkScalar dpi) {
SkFILEWStream* stream = SkNEW_ARGS(SkFILEWStream, (path));
if (!stream->isValid()) {
SkDELETE(stream);
return NULL;
}
auto delete_wstream = [](SkWStream* stream, bool) { SkDELETE(stream); };
return SkNEW_ARGS(SkDocument_PDF, (stream, delete_wstream, dpi));
}