SkPDF: in-place font subsetting

src/pdf/SkPDFBitmap.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorPriv.h"
 #include "SkData.h"
 #include "SkDeflate.h"
@@ skipping 328 matching lines @@
     }
     SkString tableString(tableArray, 3 * table->count());
     result->appendString(tableString);
     return result;
 }
 
 static void emit_image_xobject(SkWStream* stream,
                                const SkImage* image,
                                bool alpha,
                                const sk_sp<SkPDFObject>& smask,
-                               const SkPDFObjNumMap& objNumMap,
-                               const SkPDFSubstituteMap& substitutes) {
+                               const SkPDFObjNumMap& objNumMap) {
     SkBitmap bitmap;
     image_get_ro_pixels(image, &bitmap);      // TODO(halcanary): test
     SkAutoLockPixels autoLockPixels(bitmap);  // with malformed images.
 
     // Write to a temporary buffer to get the compressed length.
     SkDynamicMemoryWStream buffer;
     SkDeflateWStream deflateWStream(&buffer);
     if (alpha) {
         bitmap_alpha_to_a8(bitmap, &deflateWStream);
     } else {
@@ skipping 17 matching lines @@
         pdfDict.insertName("ColorSpace", "DeviceGray");
     } else {
         pdfDict.insertName("ColorSpace", "DeviceRGB");
     }
     if (smask) {
         pdfDict.insertObjRef("SMask", smask);
     }
     pdfDict.insertInt("BitsPerComponent", 8);
     pdfDict.insertName("Filter", "FlateDecode");
     pdfDict.insertInt("Length", asset->getLength());
-    pdfDict.emitObject(stream, objNumMap, substitutes);
+    pdfDict.emitObject(stream, objNumMap);
 
     pdf_stream_begin(stream);
     stream->writeStream(asset.get(), asset->getLength());
     pdf_stream_end(stream);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 namespace {
 // This SkPDFObject only outputs the alpha layer of the given bitmap.
 class PDFAlphaBitmap final : public SkPDFObject {
 public:
     PDFAlphaBitmap(sk_sp<SkImage> image) : fImage(std::move(image)) { SkASSERT(fImage); }
     void emitObject(SkWStream*  stream,
-                    const SkPDFObjNumMap& objNumMap,
-                    const SkPDFSubstituteMap& subs) const override {
+                    const SkPDFObjNumMap& objNumMap) const override {
         SkASSERT(fImage);
-        emit_image_xobject(stream, fImage.get(), true, nullptr, objNumMap, subs);
+        emit_image_xobject(stream, fImage.get(), true, nullptr, objNumMap);
     }
     void drop() override { fImage = nullptr; }
 
 private:
     sk_sp<SkImage> fImage;
 };
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 
 namespace {
 class PDFDefaultBitmap final : public SkPDFObject {
 public:
     void emitObject(SkWStream* stream,
-                    const SkPDFObjNumMap& objNumMap,
-                    const SkPDFSubstituteMap& subs) const override {
+                    const SkPDFObjNumMap& objNumMap) const override {
         SkASSERT(fImage);
-        emit_image_xobject(stream, fImage.get(), false, fSMask, objNumMap, subs);
+        emit_image_xobject(stream, fImage.get(), false, fSMask, objNumMap);
     }
-    void addResources(SkPDFObjNumMap* catalog,
-                      const SkPDFSubstituteMap& subs) const override {
-        SkASSERT(fImage);
-        if (fSMask.get()) {
-            SkPDFObject* obj = subs.getSubstitute(fSMask.get());
-            SkASSERT(obj);
-            catalog->addObjectRecursively(obj, subs);
-        }
+    void addResources(SkPDFObjNumMap* catalog) const override {
+        catalog->addObjectRecursively(fSMask.get());
     }
     void drop() override { fImage = nullptr; fSMask = nullptr; }
     PDFDefaultBitmap(sk_sp<SkImage> image, sk_sp<SkPDFObject> smask)
         : fImage(std::move(image)), fSMask(std::move(smask)) { SkASSERT(fImage); }
 
 private:
     sk_sp<SkImage> fImage;
     sk_sp<SkPDFObject> fSMask;
 };
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 
 namespace {
 /**
  *  This PDFObject assumes that its constructor was handed YUV or
  *  Grayscale JFIF Jpeg-encoded data that can be directly embedded
  *  into a PDF.
  */
 class PDFJpegBitmap final : public SkPDFObject {
 public:
     SkISize fSize;
     sk_sp<SkData> fData;
     bool fIsYUV;
     PDFJpegBitmap(SkISize size, SkData* data, bool isYUV)
         : fSize(size), fData(SkRef(data)), fIsYUV(isYUV) { SkASSERT(data); }
-    void emitObject(SkWStream*,
-                    const SkPDFObjNumMap&,
-                    const SkPDFSubstituteMap&) const override;
+    void emitObject(SkWStream*, const SkPDFObjNumMap&) const override;
     void drop() override { fData = nullptr; }
 };
 
 void PDFJpegBitmap::emitObject(SkWStream* stream,
-                               const SkPDFObjNumMap& objNumMap,
-                               const SkPDFSubstituteMap& substituteMap) const {
+                               const SkPDFObjNumMap& objNumMap) const {
     SkASSERT(fData);
     SkPDFDict pdfDict("XObject");
     pdfDict.insertName("Subtype", "Image");
     pdfDict.insertInt("Width", fSize.width());
     pdfDict.insertInt("Height", fSize.height());
     if (fIsYUV) {
         pdfDict.insertName("ColorSpace", "DeviceRGB");
     } else {
         pdfDict.insertName("ColorSpace", "DeviceGray");
     }
     pdfDict.insertInt("BitsPerComponent", 8);
     pdfDict.insertName("Filter", "DCTDecode");
     pdfDict.insertInt("ColorTransform", 0);
     pdfDict.insertInt("Length", SkToInt(fData->size()));
-    pdfDict.emitObject(stream, objNumMap, substituteMap);
+    pdfDict.emitObject(stream, objNumMap);
     pdf_stream_begin(stream);
     stream->write(fData->data(), fData->size());
     pdf_stream_end(stream);
 }
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 
 sk_sp<SkPDFObject> SkPDFCreateBitmapObject(sk_sp<SkImage> image,
                                            SkPixelSerializer* pixelSerializer) {
@@ skipping 32 matching lines @@
 
     sk_sp<SkPDFObject> smask;
     if (!image_compute_is_opaque(image.get())) {
         smask = sk_make_sp<PDFAlphaBitmap>(image);
     }
     #ifdef SK_PDF_IMAGE_STATS
     gRegularImageObjects.fetch_add(1);
     #endif
     return sk_make_sp<PDFDefaultBitmap>(std::move(image), std::move(smask));
 }