Implement DPI for perspective bitmaps in PDF - we save the bitmap at the resolution requested.

R=reed@google.com, vandebo@chromium.org

Review URL: https://codereview.chromium.org/54913004

git-svn-id: http://skia.googlecode.com/svn/trunk@12230 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 53 insertions, 15 deletions

diff --git a/gm/gmmain.cpp b/gm/gmmain.cpp
index d1ab966abc..86a346da66 100644
--- a/gm/gmmain.cpp
+++ b/gm/gmmain.cpp
@@ -198,6 +198,7 @@ static PipeFlagComboData gPipeWritingFlagCombos[] = {
 };
 
 static SkData* encode_to_dct_data(size_t* pixelRefOffset, const SkBitmap& bitmap);
+DECLARE_int32(pdfRasterDpi);
 
 const static ErrorCombination kDefaultIgnorableErrorTypes = ErrorCombination()
     .plus(kMissingExpectations_ErrorType)
@@ -636,7 +637,10 @@ public:
         SkMatrix initialTransform = gm->getInitialTransform();
         if (FLAGS_useDocumentInsteadOfDevice) {
             SkISize pageISize = gm->getISize();
-            SkAutoTUnref<SkDocument> pdfDoc(SkDocument::CreatePDF(&pdf, NULL, encode_to_dct_data));
+            SkAutoTUnref<SkDocument> pdfDoc(
+                    SkDocument::CreatePDF(&pdf, NULL,
+                                          encode_to_dct_data,
+                                          SkIntToScalar(FLAGS_pdfRasterDpi)));
 
             if (!pdfDoc.get()) {
                 return false;
@@ -667,6 +671,7 @@ public:
                 dev = new SkPDFDevice(pageSize, contentSize, initialTransform);
             }
             dev->setDCTEncoder(encode_to_dct_data);
+            dev->setRasterDpi(SkIntToScalar(FLAGS_pdfRasterDpi));
             SkAutoUnref aur(dev);
             SkCanvas c(dev);
             invokeGM(gm, &c, true, false);
@@ -1475,7 +1480,10 @@ DEFINE_int32(pdfJpegQuality, -1, "Encodes images in JPEG at quality level N, "
 // then we can write something reabable like --rotate centerx centery 90
 DEFINE_bool(forcePerspectiveMatrix, false, "Force a perspective matrix.");
 DEFINE_bool(useDocumentInsteadOfDevice, false, "Use SkDocument::CreateFoo instead of SkFooDevice.");
-
+DEFINE_int32(pdfRasterDpi, 72, "Scale at which at which the non suported "
+             "features in PDF are rasterized. Must be be in range 0-10000. "
+             "Default is 72. N = 0 will disable rasterizing features like "
+             "text shadows or perspective bitmaps.");
 static SkData* encode_to_dct_data(size_t* pixelRefOffset, const SkBitmap& bitmap) {
     // Filter output of warnings that JPEG is not available for the image.
     if (bitmap.width() >= 65500 || bitmap.height() >= 65500) return NULL;
diff --git a/include/pdf/SkPDFDevice.h b/include/pdf/SkPDFDevice.h
index 8e1f41823f..51d046de60 100644
--- a/include/pdf/SkPDFDevice.h
+++ b/include/pdf/SkPDFDevice.h
@@ -194,11 +194,6 @@ public:
         return *(fFontGlyphUsage.get());
     }
 
-protected:
-    virtual bool onReadPixels(const SkBitmap& bitmap, int x, int y,
-                              SkCanvas::Config8888) SK_OVERRIDE;
-
-    virtual bool allowImageFilter(SkImageFilter*) SK_OVERRIDE;
 
     /**
      *  rasterDpi - the DPI at which features without native PDF support
@@ -214,6 +209,12 @@ protected:
         fRasterDpi = rasterDpi;
     }
 
+protected:
+    virtual bool onReadPixels(const SkBitmap& bitmap, int x, int y,
+                              SkCanvas::Config8888) SK_OVERRIDE;
+
+    virtual bool allowImageFilter(SkImageFilter*) SK_OVERRIDE;
+
 private:
     // TODO(vandebo): push most of SkPDFDevice's state into a core object in
     // order to get the right access levels without using friend.
diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index de71253d92..ff7dd2cd92 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -50,6 +50,8 @@ struct TypefaceFallbackData {
 };
 #endif
 
+#define DPI_FOR_RASTER_SCALE_ONE 72
+
 // Utility functions
 
 static void emit_pdf_color(SkColor color, SkWStream* result) {
@@ -2171,6 +2173,9 @@ void SkPDFDevice::internalDrawBitmap(const SkMatrix& origMatrix,
 
     // Rasterize the bitmap using perspective in a new bitmap.
     if (origMatrix.hasPerspective()) {
+        if (fRasterDpi == 0) {
+            return;
+        }
         SkBitmap* subsetBitmap;
         if (srcRect) {
             if (!origBitmap.extractSubset(&tmpSubsetBitmap, *srcRect)) {
@@ -2183,7 +2188,8 @@ void SkPDFDevice::internalDrawBitmap(const SkMatrix& origMatrix,
         }
         srcRect = NULL;
 
-        // Transform the bitmap in the new space.
+        // Transform the bitmap in the new space, without taking into
+        // account the initial transform.
         SkPath perspectiveOutline;
         perspectiveOutline.addRect(
                 SkRect::MakeWH(SkIntToScalar(subsetBitmap->width()),
@@ -2194,8 +2200,24 @@ void SkPDFDevice::internalDrawBitmap(const SkMatrix& origMatrix,
         // Retrieve the bounds of the new shape.
         SkRect bounds = perspectiveOutline.getBounds();
 
-        // TODO(edisonn): add DPI settings. Currently 1 pixel/point, which does
-        // not look great, but it is not producing large PDFs.
+        // Transform the bitmap in the new space, taking into
+        // account the initial transform.
+        SkMatrix total = origMatrix;
+        total.postConcat(fInitialTransform);
+        total.postScale(SkIntToScalar(fRasterDpi) /
+                            SkIntToScalar(DPI_FOR_RASTER_SCALE_ONE),
+                        SkIntToScalar(fRasterDpi) /
+                            SkIntToScalar(DPI_FOR_RASTER_SCALE_ONE));
+        SkPath physicalPerspectiveOutline;
+        physicalPerspectiveOutline.addRect(
+                SkRect::MakeWH(SkIntToScalar(subsetBitmap->width()),
+                               SkIntToScalar(subsetBitmap->height())));
+        physicalPerspectiveOutline.transform(total);
+
+        SkScalar scaleX = physicalPerspectiveOutline.getBounds().width() /
+                              bounds.width();
+        SkScalar scaleY = physicalPerspectiveOutline.getBounds().height() /
+                              bounds.height();
 
         // TODO(edisonn): A better approach would be to use a bitmap shader
         // (in clamp mode) and draw a rect over the entire bounding box. Then
@@ -2204,9 +2226,12 @@ void SkPDFDevice::internalDrawBitmap(const SkMatrix& origMatrix,
         // the image.  Avoiding alpha will reduce the pdf size and generation
         // CPU time some.
 
-        perspectiveBitmap.setConfig(SkBitmap::kARGB_8888_Config,
-                                    SkScalarCeilToInt(bounds.width()),
-                                    SkScalarCeilToInt(bounds.height()));
+        perspectiveBitmap.setConfig(
+                SkBitmap::kARGB_8888_Config,
+                SkScalarCeilToInt(
+                        physicalPerspectiveOutline.getBounds().width()),
+                SkScalarCeilToInt(
+                        physicalPerspectiveOutline.getBounds().height()));
         perspectiveBitmap.allocPixels();
         perspectiveBitmap.eraseColor(SK_ColorTRANSPARENT);
 
@@ -2218,6 +2243,7 @@ void SkPDFDevice::internalDrawBitmap(const SkMatrix& origMatrix,
 
         SkMatrix offsetMatrix = origMatrix;
         offsetMatrix.postTranslate(-deltaX, -deltaY);
+        offsetMatrix.postScale(scaleX, scaleY);
 
         // Translate the draw in the new canvas, so we perfectly fit the
         // shape in the bitmap.
@@ -2228,8 +2254,11 @@ void SkPDFDevice::internalDrawBitmap(const SkMatrix& origMatrix,
         // Make sure the final bits are in the bitmap.
         canvas.flush();
 
-        // In the new space, we use the identity matrix translated.
-        matrix.setTranslate(deltaX, deltaY);
+        // In the new space, we use the identity matrix translated
+        // and scaled to reflect DPI.
+        matrix.setScale(1 / scaleX, 1 / scaleY);
+        matrix.postTranslate(deltaX, deltaY);
+
         perspectiveBounds.setRect(
                 SkIRect::MakeXYWH(SkScalarFloorToInt(bounds.x()),
                                   SkScalarFloorToInt(bounds.y()),