SkPDF: PDFDevice::ContentEntry now implemented with SinglyLinkedList

src/pdf/SkPDFDevice.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPDFDevice_DEFINED
 #define SkPDFDevice_DEFINED
 
 #include "SkBitmap.h"
 #include "SkBitmapKey.h"
 #include "SkCanvas.h"
 #include "SkClipStack.h"
 #include "SkData.h"
 #include "SkDevice.h"
 #include "SkPaint.h"
 #include "SkPath.h"
 #include "SkPicture.h"
 #include "SkRect.h"
 #include "SkRefCnt.h"
 #include "SkStream.h"
 #include "SkTDArray.h"
 #include "SkTemplates.h"
 
+#include "SkSinglyLinkedList.h"
+
 class SkPDFArray;
 class SkPDFCanon;
 class SkPDFDevice;
 class SkPDFDocument;
 class SkPDFDict;
 class SkPDFFont;
 class SkPDFFormXObject;
 class SkPDFGlyphSetMap;
 class SkPDFGraphicState;
 class SkPDFObject;
 class SkPDFShader;
 class SkPDFStream;
 class SkRRect;
 
-// Private classes.
-struct ContentEntry;
-struct GraphicStateEntry;
-
 /** \class SkPDFDevice
 
     The drawing context for the PDF backend.
 */
 class SkPDFDevice final : public SkBaseDevice {
 public:
     /** Create a PDF drawing context.  SkPDFDevice applies a
      *  scale-and-translate transform to move the origin from the
      *  bottom left (PDF default) to the top left (Skia default).
      *  @param pageSize Page size in point units.
@@ skipping 114 matching lines @@
 
     /** Returns a SkPDFGlyphSetMap which represents glyph usage of every font
      *  that shows on this device.
      */
     const SkPDFGlyphSetMap& getFontGlyphUsage() const {
         return *(fFontGlyphUsage.get());
     }
 
     SkPDFCanon* getCanon() const;
 
+    // It is important to not confuse GraphicStateEntry with SkPDFGraphicState, the
+    // later being our representation of an object in the PDF file.
+    struct GraphicStateEntry {
+        GraphicStateEntry();
+
+        // Compare the fields we care about when setting up a new content entry.
+        bool compareInitialState(const GraphicStateEntry& b);
+
+        SkMatrix fMatrix;
+        // We can't do set operations on Paths, though PDF natively supports
+        // intersect.  If the clip stack does anything other than intersect,
+        // we have to fall back to the region.  Treat fClipStack as authoritative.
+        // See https://bugs.skia.org/221
+        SkClipStack fClipStack;
+        SkRegion fClipRegion;
+
+        // When emitting the content entry, we will ensure the graphic state
+        // is set to these values first.
+        SkColor fColor;
+        SkScalar fTextScaleX;  // Zero means we don't care what the value is.
+        SkPaint::Style fTextFill;  // Only if TextScaleX is non-zero.
+        int fShaderIndex;
+        int fGraphicStateIndex;
+
+        // We may change the font (i.e. for Type1 support) within a
+        // ContentEntry.  This is the one currently in effect, or nullptr if none.
+        SkPDFFont* fFont;
+        // In PDF, text size has no default value. It is only valid if fFont is
+        // not nullptr.
+        SkScalar fTextSize;
+    };
+
 protected:
     const SkBitmap& onAccessBitmap() override {
         return fLegacyBitmap;
     }
 
     sk_sp<SkSurface> makeSurface(const SkImageInfo&, const SkSurfaceProps&) override;
 
     void drawAnnotation(const SkDraw&, const SkRect&, const char key[], SkData* value) override;
 
 private:
@@ skipping 37 matching lines @@
 
     SkTArray<RectWithData> fLinkToURLs;
     SkTArray<RectWithData> fLinkToDestinations;
     SkTArray<NamedDestination> fNamedDestinations;
 
     SkTDArray<SkPDFObject*> fGraphicStateResources;
     SkTDArray<SkPDFObject*> fXObjectResources;
     SkTDArray<SkPDFFont*> fFontResources;
     SkTDArray<SkPDFObject*> fShaderResources;
 
-    std::unique_ptr<ContentEntry> fContentEntries;
-    ContentEntry* fLastContentEntry;
+    struct ContentEntry {
+        GraphicStateEntry fState;
+        SkDynamicMemoryWStream fContent;
+    };
+    SkSinglyLinkedList<ContentEntry> fContentEntries;
 
     const SkClipStack* fClipStack;
 
     // Glyph ids used for each font on this device.
     std::unique_ptr<SkPDFGlyphSetMap> fFontGlyphUsage;
 
     SkScalar fRasterDpi;
 
     SkBitmap fLegacyBitmap;
 
@@ skipping 66 matching lines @@
 
     typedef SkBaseDevice INHERITED;
 
     // TODO(edisonn): Only SkDocument_PDF and SkPDFImageShader should be able to create
     // an SkPDFDevice
     //friend class SkDocument_PDF;
     //friend class SkPDFImageShader;
 };
 
 #endif