[PDF] Fix clipping in xfermode improvement.

src/pdf/SkPDFDevice.cpp

 /*
  * 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 "SkPDFDevice.h"
 
 #include "SkAnnotation.h"
@@ skipping 1894 matching lines @@
     }
     if (!dst) {
         SkASSERT(xfermode == SkXfermode::kSrc_Mode ||
                  xfermode == SkXfermode::kSrcOut_Mode);
         return;
     }
 
     ContentEntry* contentEntries = getContentEntries()->get();
     SkASSERT(dst);
     SkASSERT(!contentEntries->fNext.get());
-    // We have to make a copy of these here because changing the current
-    // content into a form-xobject will destroy them.
+    // Changing the current content into a form-xobject will destroy the clip
+    // objects which is fine since the xobject will already be clipped. However
+    // if source has shape, we need to clip it too, so a copy of the clip is
+    // saved.
     SkClipStack clipStack = contentEntries->fState.fClipStack;
     SkRegion clipRegion = contentEntries->fState.fClipRegion;
 
     SkMatrix identity;
     identity.reset();
     SkPaint stockPaint;
 
     SkAutoTUnref<SkPDFFormXObject> srcFormXObject;
     if (isContentEmpty()) {
         // If nothing was drawn and there's no shape, then the draw was a
         // no-op, but dst needs to be restored for that to be true.
         // If there is shape, then an empty source with Src, SrcIn, SrcOut,
         // DstIn, DstAtop or Modulate reduces to Clear and DstOut or SrcAtop
         // reduces to Dst.
         if (shape == NULL || xfermode == SkXfermode::kDstOut_Mode ||
                 xfermode == SkXfermode::kSrcATop_Mode) {
-            ScopedContentEntry content(this, &clipStack, clipRegion, identity,
+            ScopedContentEntry content(this, &fExistingClipStack,
+                                       fExistingClipRegion, identity,
                                        stockPaint);
             SkPDFUtils::DrawFormXObject(this->addXObjectResource(dst),
                                         &content.entry()->fContent);
             return;
         } else {
             xfermode = SkXfermode::kClear_Mode;
         }
     } else {
         SkASSERT(!fContentEntries->fNext.get());
         srcFormXObject.reset(createFormXObjectFromDevice());
     }
 
     // TODO(vandebo) srcFormXObject may contain alpha, but here we want it
     // without alpha.
     if (xfermode == SkXfermode::kSrcATop_Mode) {
         // TODO(vandebo): In order to properly support SrcATop we have to track
         // the shape of what's been drawn at all times. It's the intersection of
         // the non-transparent parts of the device and the outlines (shape) of
         // all images and devices drawn.
         drawFormXObjectWithMask(addXObjectResource(srcFormXObject.get()), dst,
-                                &clipStack, clipRegion,
+                                &fExistingClipStack, fExistingClipRegion,
                                 SkXfermode::kSrcOver_Mode, true);
     } else {
         SkAutoTUnref<SkPDFFormXObject> dstMaskStorage;
         SkPDFFormXObject* dstMask = srcFormXObject.get();
         if (shape != NULL) {
             // Draw shape into a form-xobject.
             SkDraw d;
             d.fMatrix = &identity;
             d.fClip = &clipRegion;
             d.fClipStack = &clipStack;
             SkPaint filledPaint;
             filledPaint.setColor(SK_ColorBLACK);
             filledPaint.setStyle(SkPaint::kFill_Style);
             this->drawPath(d, *shape, filledPaint, NULL, true);
 
             dstMaskStorage.reset(createFormXObjectFromDevice());
             dstMask = dstMaskStorage.get();
         }
-        drawFormXObjectWithMask(addXObjectResource(dst), dstMask, &clipStack,
-                                clipRegion, SkXfermode::kSrcOver_Mode, true);
+        drawFormXObjectWithMask(addXObjectResource(dst), dstMask,
+                                &fExistingClipStack, fExistingClipRegion,
+                                SkXfermode::kSrcOver_Mode, true);
     }
 
     if (xfermode == SkXfermode::kClear_Mode) {
         return;
     } else if (xfermode == SkXfermode::kSrc_Mode ||
             xfermode == SkXfermode::kDstATop_Mode) {
-        ScopedContentEntry content(this, &clipStack, clipRegion, identity,
-                                   stockPaint);
+        ScopedContentEntry content(this, &fExistingClipStack,
+                                   fExistingClipRegion, identity, stockPaint);
         if (content.entry()) {
             SkPDFUtils::DrawFormXObject(
                     this->addXObjectResource(srcFormXObject.get()),
                     &content.entry()->fContent);
         }
         if (xfermode == SkXfermode::kSrc_Mode) {
             return;
         }
     } else if (xfermode == SkXfermode::kSrcATop_Mode) {
-        ScopedContentEntry content(this, &clipStack, clipRegion, identity,
-                                   stockPaint);
+        ScopedContentEntry content(this, &fExistingClipStack,
+                                   fExistingClipRegion, identity, stockPaint);
         if (content.entry()) {
             SkPDFUtils::DrawFormXObject(this->addXObjectResource(dst),
                                         &content.entry()->fContent);
         }
     }
 
     SkASSERT(xfermode == SkXfermode::kSrcIn_Mode   ||
              xfermode == SkXfermode::kDstIn_Mode   ||
              xfermode == SkXfermode::kSrcOut_Mode  ||
              xfermode == SkXfermode::kDstOut_Mode  ||
              xfermode == SkXfermode::kSrcATop_Mode ||
              xfermode == SkXfermode::kDstATop_Mode ||
              xfermode == SkXfermode::kModulate_Mode);
 
-    ScopedContentEntry inShapeContentEntry(this, &fExistingClipStack,

[vandebo (ex-Chrome), 2013/12/17 23:11:03]

This was dead code - inShapeContentEntry is not used.

-                                           fExistingClipRegion, identity,
-                                           stockPaint);
-    if (!inShapeContentEntry.entry()) {

[vandebo (ex-Chrome), 2013/12/17 23:11:03]

This can't be true because fExistingClipRegion is not empty and xfermode is
SrcOver.

-        return;
-    }
-
     if (xfermode == SkXfermode::kSrcIn_Mode ||
             xfermode == SkXfermode::kSrcOut_Mode ||
             xfermode == SkXfermode::kSrcATop_Mode) {
         drawFormXObjectWithMask(addXObjectResource(srcFormXObject.get()), dst,
-                                &clipStack, clipRegion,
+                                &fExistingClipStack, fExistingClipRegion,
                                 SkXfermode::kSrcOver_Mode,
                                 xfermode == SkXfermode::kSrcOut_Mode);
     } else {
         SkXfermode::Mode mode = SkXfermode::kSrcOver_Mode;
         if (xfermode == SkXfermode::kModulate_Mode) {
             drawFormXObjectWithMask(addXObjectResource(srcFormXObject.get()),
-                                    dst, &clipStack, clipRegion,
+                                    dst, &fExistingClipStack,
+                                    fExistingClipRegion,
                                     SkXfermode::kSrcOver_Mode, false);
             mode = SkXfermode::kMultiply_Mode;
         }
         drawFormXObjectWithMask(addXObjectResource(dst), srcFormXObject.get(),
-                                &clipStack, clipRegion, mode,
+                                &fExistingClipStack, fExistingClipRegion, mode,
                                 xfermode == SkXfermode::kDstOut_Mode);
     }
 }
 
 bool SkPDFDevice::isContentEmpty() {
     ContentEntry* contentEntries = getContentEntries()->get();
     if (!contentEntries || contentEntries->fContent.getOffset() == 0) {
         SkASSERT(!contentEntries || !contentEntries->fNext.get());
         return true;
     }
@@ skipping 288 matching lines @@
 }
 
 bool SkPDFDevice::onReadPixels(const SkBitmap& bitmap, int x, int y,
                                SkCanvas::Config8888) {
     return false;
 }
 
 bool SkPDFDevice::allowImageFilter(SkImageFilter*) {
     return false;
 }