SkPDF: with opaque draws, treat SRC mode as SRC_OVER

src/pdf/SkPDFDevice.cpp

Index: src/pdf/SkPDFDevice.cpp
diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index 3b0d6f72ae5a1fdeaf51e41f7e2c536486c61084..d4cee9f464f33b3d44ec078a8a2b97dd2f78008e 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -37,6 +37,19 @@
 
 // Utility functions
 
+static void fix_paint_xfermode(SkPaint* paint) {

[reed1, 2015/05/26 16:28:23]

"fix" is not very descriptive, if I'm trying to understand what this function
does.

[hal.canary, 2015/05/26 18:24:19]

Done.

+    SkXfermode::Mode mode = SkXfermode::kSrcOver_Mode;
+    if (paint->getXfermode() && paint->getXfermode()->asMode(&mode)) {
+        if (mode == SkXfermode::kSrc_Mode &&
+            paint->getAlpha() == SK_AlphaOPAQUE && !paint->getColorFilter() &&
+            !paint->getPathEffect() && !paint->getMaskFilter() &&
+            !paint->getRasterizer() && !paint->getImageFilter() &&
+            !paint->getLooper()) {
+            paint->setXfermodeMode(SkXfermode::kSrcOver_Mode);
+        }
+    }
+}
+
 static void emit_pdf_color(SkColor color, SkWStream* result) {
     SkASSERT(SkColorGetA(color) == 0xFF);  // We handle alpha elsewhere.
     SkScalar colorScale = SkScalarInvert(0xFF);
@@ -756,6 +769,8 @@ void SkPDFDevice::cleanUp(bool clearFontUsage) {
 
 void SkPDFDevice::drawPaint(const SkDraw& d, const SkPaint& paint) {
     SkPaint newPaint = paint;
+    fix_paint_xfermode(&newPaint);
+
     newPaint.setStyle(SkPaint::kFill_Style);
     ScopedContentEntry content(this, d, newPaint);
     internalDrawPaint(newPaint, content.entry());
@@ -779,9 +794,14 @@ void SkPDFDevice::internalDrawPaint(const SkPaint& paint,
                           &contentEntry->fContent);
 }
 
-void SkPDFDevice::drawPoints(const SkDraw& d, SkCanvas::PointMode mode,
-                             size_t count, const SkPoint* points,
-                             const SkPaint& passedPaint) {
+void SkPDFDevice::drawPoints(const SkDraw& d,
+                             SkCanvas::PointMode mode,
+                             size_t count,
+                             const SkPoint* points,
+                             const SkPaint& srcPaint) {
+    SkPaint passedPaint = srcPaint;
+    fix_paint_xfermode(&passedPaint);
+
     if (count == 0) {
         return;
     }
@@ -866,8 +886,11 @@ void SkPDFDevice::drawPoints(const SkDraw& d, SkCanvas::PointMode mode,
     }
 }
 
-void SkPDFDevice::drawRect(const SkDraw& d, const SkRect& rect,
-                           const SkPaint& paint) {
+void SkPDFDevice::drawRect(const SkDraw& d,
+                           const SkRect& rect,
+                           const SkPaint& srcPaint) {
+    SkPaint paint = srcPaint;
+    fix_paint_xfermode(&paint);
     SkRect r = rect;
     r.sort();
 
@@ -894,21 +917,33 @@ void SkPDFDevice::drawRect(const SkDraw& d, const SkRect& rect,
                           &content.entry()->fContent);
 }
 
-void SkPDFDevice::drawRRect(const SkDraw& draw, const SkRRect& rrect, const SkPaint& paint) {
+void SkPDFDevice::drawRRect(const SkDraw& draw,
+                            const SkRRect& rrect,
+                            const SkPaint& srcPaint) {
+    SkPaint paint = srcPaint;
+    fix_paint_xfermode(&paint);
     SkPath  path;
     path.addRRect(rrect);
     this->drawPath(draw, path, paint, NULL, true);
 }
 
-void SkPDFDevice::drawOval(const SkDraw& draw, const SkRect& oval, const SkPaint& paint) {
+void SkPDFDevice::drawOval(const SkDraw& draw,
+                           const SkRect& oval,
+                           const SkPaint& srcPaint) {
+    SkPaint paint = srcPaint;
+    fix_paint_xfermode(&paint);
     SkPath  path;
     path.addOval(oval);
     this->drawPath(draw, path, paint, NULL, true);
 }
 
-void SkPDFDevice::drawPath(const SkDraw& d, const SkPath& origPath,
-                           const SkPaint& paint, const SkMatrix* prePathMatrix,
+void SkPDFDevice::drawPath(const SkDraw& d,
+                           const SkPath& origPath,
+                           const SkPaint& srcPaint,
+                           const SkMatrix* prePathMatrix,
                            bool pathIsMutable) {
+    SkPaint paint = srcPaint;
+    fix_paint_xfermode(&paint);
     SkPath modifiedPath;
     SkPath* pathPtr = const_cast<SkPath*>(&origPath);
 
@@ -967,8 +1002,13 @@ void SkPDFDevice::drawPath(const SkDraw& d, const SkPath& origPath,
 
 void SkPDFDevice::drawBitmapRect(const SkDraw& draw, const SkBitmap& bitmap,
                                  const SkRect* src, const SkRect& dst,
-                                 const SkPaint& paint,
+                                 const SkPaint& srcPaint,
                                  SkCanvas::DrawBitmapRectFlags flags) {
+    SkPaint paint = srcPaint;
+    if (bitmap.isOpaque()) {
+        fix_paint_xfermode(&paint);
+    }
+
     // TODO: this code path must be updated to respect the flags parameter
     SkMatrix    matrix;
     SkRect      bitmapBounds, tmpSrc, tmpDst;
@@ -1023,7 +1063,12 @@ void SkPDFDevice::drawBitmapRect(const SkDraw& draw, const SkBitmap& bitmap,
 }
 
 void SkPDFDevice::drawBitmap(const SkDraw& d, const SkBitmap& bitmap,
-                             const SkMatrix& matrix, const SkPaint& paint) {
+                             const SkMatrix& matrix, const SkPaint& srcPaint) {
+    SkPaint paint = srcPaint;
+    if (bitmap.isOpaque()) {
+        fix_paint_xfermode(&paint);
+    }
+
     if (d.fClip->isEmpty()) {
         return;
     }
@@ -1035,7 +1080,12 @@ void SkPDFDevice::drawBitmap(const SkDraw& d, const SkBitmap& bitmap,
 }
 
 void SkPDFDevice::drawSprite(const SkDraw& d, const SkBitmap& bitmap,
-                             int x, int y, const SkPaint& paint) {
+                             int x, int y, const SkPaint& srcPaint) {
+    SkPaint paint = srcPaint;
+    if (bitmap.isOpaque()) {
+        fix_paint_xfermode(&paint);
+    }
+
     if (d.fClip->isEmpty()) {
         return;
     }
@@ -1082,7 +1132,10 @@ static SkString format_wide_string(const uint16_t* input,
 }
 
 void SkPDFDevice::drawText(const SkDraw& d, const void* text, size_t len,
-                           SkScalar x, SkScalar y, const SkPaint& paint) {
+                           SkScalar x, SkScalar y, const SkPaint& srcPaint) {
+    SkPaint paint = srcPaint;
+    fix_paint_xfermode(&paint);
+
     NOT_IMPLEMENTED(paint.getMaskFilter() != NULL, false);
     if (paint.getMaskFilter() != NULL) {
         // Don't pretend we support drawing MaskFilters, it makes for artifacts
@@ -1131,7 +1184,10 @@ void SkPDFDevice::drawText(const SkDraw& d, const void* text, size_t len,
 
 void SkPDFDevice::drawPosText(const SkDraw& d, const void* text, size_t len,
                               const SkScalar pos[], int scalarsPerPos,
-                              const SkPoint& offset, const SkPaint& paint) {
+                              const SkPoint& offset, const SkPaint& srcPaint) {
+    SkPaint paint = srcPaint;
+    fix_paint_xfermode(&paint);
+
     NOT_IMPLEMENTED(paint.getMaskFilter() != NULL, false);
     if (paint.getMaskFilter() != NULL) {
         // Don't pretend we support drawing MaskFilters, it makes for artifacts