PDF: Correctly embed JPEG images directly into PDF output.

src/pdf/SkPDFBitmap.cpp

Index: src/pdf/SkPDFBitmap.cpp
diff --git a/src/pdf/SkPDFBitmap.cpp b/src/pdf/SkPDFBitmap.cpp
index 765016dcf2d0d06f05b25cca2747649513ad0ef5..42a5841b390eee67e84b6b02efe1e8bf0ec1ea77 100644
--- a/src/pdf/SkPDFBitmap.cpp
+++ b/src/pdf/SkPDFBitmap.cpp
@@ -6,10 +6,13 @@
  */
 
 #include "SkColorPriv.h"
+#include "SkData.h"
 #include "SkFlate.h"
+#include "SkImageGenerator.h"
 #include "SkPDFBitmap.h"
 #include "SkPDFCanon.h"
 #include "SkPDFCatalog.h"
+#include "SkPixelRef.h"
 #include "SkStream.h"
 #include "SkUnPreMultiply.h"
 
@@ -248,7 +251,6 @@ public:
 
 private:
     const SkBitmap fBitmap;
-    void emitDict(SkWStream*, SkPDFCatalog*, size_t) const;
 };
 
 void PDFAlphaBitmap::emitObject(SkWStream* stream, SkPDFCatalog* catalog) {
@@ -263,15 +265,6 @@ void PDFAlphaBitmap::emitObject(SkWStream* stream, SkPDFCatalog* catalog) {
     deflateWStream.finalize();  // call before detachAsStream().
     SkAutoTDelete<SkStreamAsset> asset(buffer.detachAsStream());
 
-    this->emitDict(stream, catalog, asset->getLength());
-    pdf_stream_begin(stream);
-    stream->writeStream(asset.get(), asset->getLength());
-    pdf_stream_end(stream);
-}
-
-void PDFAlphaBitmap::emitDict(SkWStream* stream,
-                              SkPDFCatalog* catalog,
-                              size_t length) const {
     SkPDFDict pdfDict("XObject");
     pdfDict.insertName("Subtype", "Image");
     pdfDict.insertInt("Width", fBitmap.width());
@@ -279,14 +272,29 @@ void PDFAlphaBitmap::emitDict(SkWStream* stream,
     pdfDict.insertName("ColorSpace", "DeviceGray");
     pdfDict.insertInt("BitsPerComponent", 8);
     pdfDict.insertName("Filter", "FlateDecode");
-    pdfDict.insertInt("Length", length);
+    pdfDict.insertInt("Length", asset->getLength());
     pdfDict.emitObject(stream, catalog);
+
+    pdf_stream_begin(stream);
+    stream->writeStream(asset.get(), asset->getLength());
+    pdf_stream_end(stream);
 }
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 
-void SkPDFBitmap::addResources(SkPDFCatalog* catalog) const {
+namespace {
+class PDFBitmap : public SkPDFBitmap {

[mtklein, 2015/03/25 21:36:53]

Oh come on.

[hal.canary, 2015/04/17 18:57:13]

Done.

+public:
+    const SkAutoTUnref<SkPDFObject> fSMask;
+    void emitObject(SkWStream*, SkPDFCatalog*) SK_OVERRIDE;
+    void addResources(SkPDFCatalog*) const SK_OVERRIDE;
+    PDFBitmap(const SkBitmap& bm, SkPDFObject* smask)
+        : SkPDFBitmap(bm), fSMask(smask) {}
+};
+}  // namespace
+
+void PDFBitmap::addResources(SkPDFCatalog* catalog) const {
     if (fSMask.get()) {
         if (catalog->addObject(fSMask.get())) {
             fSMask->addResources(catalog);
@@ -294,24 +302,6 @@ void SkPDFBitmap::addResources(SkPDFCatalog* catalog) const {
     }
 }
 
-void SkPDFBitmap::emitObject(SkWStream* stream, SkPDFCatalog* catalog) {
-    SkAutoLockPixels autoLockPixels(fBitmap);
-    SkASSERT(fBitmap.colorType() != kIndex_8_SkColorType ||
-             fBitmap.getColorTable());
-
-    // Write to a temporary buffer to get the compressed length.
-    SkDynamicMemoryWStream buffer;
-    SkDeflateWStream deflateWStream(&buffer);
-    bitmap_to_pdf_pixels(fBitmap, &deflateWStream);
-    deflateWStream.finalize();  // call before detachAsStream().
-    SkAutoTDelete<SkStreamAsset> asset(buffer.detachAsStream());
-
-    this->emitDict(stream, catalog, asset->getLength());
-    pdf_stream_begin(stream);
-    stream->writeStream(asset.get(), asset->getLength());
-    pdf_stream_end(stream);
-}
-
 static SkPDFArray* make_indexed_color_space(const SkColorTable* table) {
     SkPDFArray* result = SkNEW(SkPDFArray);
     result->reserve(4);
@@ -342,9 +332,18 @@ static SkPDFArray* make_indexed_color_space(const SkColorTable* table) {
     return result;
 }
 
-void SkPDFBitmap::emitDict(SkWStream* stream,
-                           SkPDFCatalog* catalog,
-                           size_t length) const {
+void PDFBitmap::emitObject(SkWStream* stream, SkPDFCatalog* catalog) {
+    SkAutoLockPixels autoLockPixels(fBitmap);
+    SkASSERT(fBitmap.colorType() != kIndex_8_SkColorType ||
+             fBitmap.getColorTable());
+
+    // Write to a temporary buffer to get the compressed length.
+    SkDynamicMemoryWStream buffer;
+    SkDeflateWStream deflateWStream(&buffer);
+    bitmap_to_pdf_pixels(fBitmap, &deflateWStream);
+    deflateWStream.finalize();  // call before detachAsStream().
+    SkAutoTDelete<SkStreamAsset> asset(buffer.detachAsStream());
+
     SkPDFDict pdfDict("XObject");
     pdfDict.insertName("Subtype", "Image");
     pdfDict.insertInt("Width", fBitmap.width());
@@ -363,15 +362,13 @@ void SkPDFBitmap::emitDict(SkWStream* stream,
         pdfDict.insert("SMask", new SkPDFObjRef(fSMask))->unref();
     }
     pdfDict.insertName("Filter", "FlateDecode");
-    pdfDict.insertInt("Length", length);
+    pdfDict.insertInt("Length", asset->getLength());
     pdfDict.emitObject(stream, catalog);
-}
-
-SkPDFBitmap::SkPDFBitmap(const SkBitmap& bm,
-                         SkPDFObject* smask)
-    : fBitmap(bm), fSMask(smask) {}
 
-SkPDFBitmap::~SkPDFBitmap() {}
+    pdf_stream_begin(stream);
+    stream->writeStream(asset.get(), asset->getLength());
+    pdf_stream_end(stream);
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -384,6 +381,55 @@ static const SkBitmap& immutable_bitmap(const SkBitmap& bm, SkBitmap* copy) {
     return *copy;
 }
 
+namespace {
+/**
+ *  This PDFObject assumes that its constructor was handed YUV JFIF
+ *  Jpeg-encoded data that can be directly embedded into a PDF.
+ */
+class PDFJpegBitmap : public SkPDFBitmap {
+public:
+    SkAutoTUnref<SkData> fData;
+    PDFJpegBitmap(const SkBitmap& bm, SkData* data)
+        : SkPDFBitmap(bm), fData(SkRef(data)) {}
+    void emitObject(SkWStream*, SkPDFCatalog*) SK_OVERRIDE;
+};
+
+void PDFJpegBitmap::emitObject(SkWStream* stream, SkPDFCatalog* catalog) {
+    SkPDFDict pdfDict("XObject");
+    pdfDict.insertName("Subtype", "Image");
+    pdfDict.insertInt("Width", fBitmap.width());
+    pdfDict.insertInt("Height", fBitmap.height());
+    pdfDict.insertName("ColorSpace", "DeviceRGB");
+    pdfDict.insertInt("BitsPerComponent", 8);
+    pdfDict.insertName("Filter", "DCTDecode");
+    pdfDict.insertInt("ColorTransform", 0);
+    pdfDict.insertInt("Length", SkToInt(fData->size()));
+    pdfDict.emitObject(stream, catalog);
+    pdf_stream_begin(stream);
+    stream->write(fData->data(), fData->size());
+    pdf_stream_end(stream);
+}
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+
+static bool is_jfif_yuv_jpeg(SkData* data) {
+    const uint8_t bytesZeroToThree[] = {0xFF, 0xD8, 0xFF, 0xE0};
+    const uint8_t bytesSixToTen[] = {'J', 'F', 'I', 'F', 0};
+    // 0   1   2   3   4   5   6   7   8   9   10
+    // FF  D8  FF  E0  ??  ??  'J' 'F' 'I' 'F' 00 ...
+    if (data->size() < 11 ||
+        0 != memcmp(data->bytes(), bytesZeroToThree,
+                    sizeof(bytesZeroToThree)) ||
+        0 != memcmp(data->bytes() + 6, bytesSixToTen, sizeof(bytesSixToTen))) {
+        return false;
+    }
+    SkAutoTDelete<SkImageGenerator> gen(SkImageGenerator::NewFromData(data));
+    SkISize sizes[3];
+    // Only YUV JPEG allows access to YUV planes.
+    return gen && gen->getYUV8Planes(sizes, NULL, NULL, NULL);
+}
+
 SkPDFBitmap* SkPDFBitmap::Create(SkPDFCanon* canon, const SkBitmap& bitmap) {
     SkASSERT(canon);
     if (!SkColorTypeIsValid(bitmap.colorType()) ||
@@ -398,11 +444,23 @@ SkPDFBitmap* SkPDFBitmap::Create(SkPDFCanon* canon, const SkBitmap& bitmap) {
     if (SkPDFBitmap* canonBitmap = canon->findBitmap(bm)) {
         return SkRef(canonBitmap);
     }
+
+    if (bm.pixelRef() && bm.pixelRefOrigin().isZero() &&
+        bm.dimensions() == bm.pixelRef()->info().dimensions()) {
+        // Requires the bitmap to be backed by lazy pixels.
+        SkAutoTUnref<SkData> data(bm.pixelRef()->refEncodedData());
+        if (data && is_jfif_yuv_jpeg(data)) {
+            SkPDFBitmap* pdfBitmap = SkNEW_ARGS(PDFJpegBitmap, (bm, data));
+            canon->addBitmap(pdfBitmap);
+            return pdfBitmap;
+        }
+    }
+
     SkPDFObject* smask = NULL;
     if (!bm.isOpaque() && !SkBitmap::ComputeIsOpaque(bm)) {
         smask = SkNEW_ARGS(PDFAlphaBitmap, (bm));
     }
-    SkPDFBitmap* pdfBitmap = SkNEW_ARGS(SkPDFBitmap, (bm, smask));
+    SkPDFBitmap* pdfBitmap = SkNEW_ARGS(PDFBitmap, (bm, smask));
     canon->addBitmap(pdfBitmap);
     return pdfBitmap;
 }