SkPDF: scale entire canvas for non-standard rasterDpi

TODO: add better testing around this.

BUG: chromium:481429

Change-Id: I1296fae3fc9775febf17bba75722c30f48d67a95
Reviewed-on: https://skia-review.googlesource.com/127051
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>

3 files changed, 17 insertions, 14 deletions

diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index c18219ab0d..ced94ce9a9 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -508,8 +508,9 @@ void SkPDFDevice::setFlip() {
     // natively has the origin at the bottom left. This matrix
     // corrects for that.  But that only needs to be done once, we
     // don't do it when layering.
-    fInitialTransform.setTranslate(0, SkIntToScalar(fPageSize.fHeight));
-    fInitialTransform.preScale(SK_Scalar1, -SK_Scalar1);
+    SkScalar rasterScale = SkPDFUtils::kDpiForRasterScaleOne / fDocument->rasterDpi();
+    fInitialTransform.setConcat(SkMatrix::MakeScale(rasterScale, -rasterScale),
+                                SkMatrix::MakeTrans(0, -fPageSize.fHeight));
 }
 
 SkPDFDevice::~SkPDFDevice() {
@@ -797,9 +798,6 @@ void SkPDFDevice::internalDrawPathWithFilter(const SkClipStack& clipStack,
                                      : SkStrokeRec::kHairline_InitStyle;
     path.transform(ctm, &path);
 
-    // TODO(halcanary): respect fDocument->rasterDpi().
-    //        SkScalar rasterScale = (float)rasterDpi / SkPDFUtils::kDpiForRasterScaleOne;
-    // Would it be easier to just change the device size (and pre-scale the canvas)?
     SkIRect bounds = clipStack.bounds(this->bounds()).roundOut();
     SkMask sourceMask;
     if (!SkDraw::DrawToMask(path, &bounds, paint->getMaskFilter(), &SkMatrix::I(),
@@ -2157,7 +2155,6 @@ void SkPDFDevice::internalDrawImageRect(SkKeyedImage imageSubset,
 
     // Rasterize the bitmap using perspective in a new bitmap.
     if (transform.hasPerspective()) {
-        SkASSERT(fDocument->rasterDpi() > 0);
         // Transform the bitmap in the new space, without taking into
         // account the initial transform.
         SkPath perspectiveOutline;
@@ -2173,9 +2170,6 @@ void SkPDFDevice::internalDrawImageRect(SkKeyedImage imageSubset,
         // account the initial transform.
         SkMatrix total = transform;
         total.postConcat(fInitialTransform);
-        SkScalar dpiScale = SkIntToScalar(fDocument->rasterDpi()) /
-                            SkIntToScalar(SkPDFUtils::kDpiForRasterScaleOne);
-        total.postScale(dpiScale, dpiScale);
 
         SkPath physicalPerspectiveOutline;
         physicalPerspectiveOutline.addRect(imageBounds);
diff --git a/src/pdf/SkPDFDocument.cpp b/src/pdf/SkPDFDocument.cpp
index b06b8b1a96..8219ad385e 100644
--- a/src/pdf/SkPDFDocument.cpp
+++ b/src/pdf/SkPDFDocument.cpp
@@ -207,11 +207,14 @@ SkCanvas* SkPDFDocument::onBeginPage(SkScalar width, SkScalar height) {
             fObjectSerializer.serializeObjects(this->getStream());
         }
     }
-    SkISize pageSize = SkISize::Make(
-            SkScalarRoundToInt(width), SkScalarRoundToInt(height));
+    SkScalar rasterScale = this->rasterDpi() / SkPDFUtils::kDpiForRasterScaleOne;
+    SkISize pageSize = {SkScalarRoundToInt(width  * rasterScale),
+                        SkScalarRoundToInt(height * rasterScale)};
+
     fPageDevice = sk_make_sp<SkPDFDevice>(pageSize, this);
     fPageDevice->setFlip();  // Only the top-level device needs to be flipped.
     fCanvas.reset(new SkCanvas(fPageDevice));
+    fCanvas->scale(rasterScale, rasterScale);
     return fCanvas.get();
 }
 
@@ -222,7 +225,13 @@ void SkPDFDocument::onEndPage() {
     SkASSERT(fPageDevice);
     auto page = sk_make_sp<SkPDFDict>("Page");
     page->insertObject("Resources", fPageDevice->makeResourceDict());
-    page->insertObject("MediaBox", fPageDevice->copyMediaBox());
+
+    SkScalar rasterScale =  SkPDFUtils::kDpiForRasterScaleOne / this->rasterDpi();
+
+    SkISize pageSize = fPageDevice->imageInfo().dimensions();
+    page->insertObject("MediaBox", SkPDFUtils::RectToArray(
+                {0, 0, pageSize.width() * rasterScale, pageSize.height() * rasterScale}));
+
     auto annotations = sk_make_sp<SkPDFArray>();
     fPageDevice->appendAnnotations(annotations.get());
     if (annotations->size() > 0) {
diff --git a/src/pdf/SkPDFShader.cpp b/src/pdf/SkPDFShader.cpp
index 63611d43d5..0f1fa4da15 100644
--- a/src/pdf/SkPDFShader.cpp
+++ b/src/pdf/SkPDFShader.cpp
@@ -283,8 +283,8 @@ static sk_sp<SkPDFObject> make_fallback_shader(SkPDFDocument* doc,
     }
     // Clamp the bitmap size to about 1M pixels
     static const SkScalar kMaxBitmapArea = 1024 * 1024;
-    SkScalar rasterScale = SkIntToScalar(doc->rasterDpi()) / SkPDFUtils::kDpiForRasterScaleOne;
-    SkScalar bitmapArea = rasterScale * surfaceBBox.width() * rasterScale * surfaceBBox.height();
+    SkScalar bitmapArea = surfaceBBox.width() * surfaceBBox.height();
+    SkScalar rasterScale = 1.0f;
     if (bitmapArea > kMaxBitmapArea) {
         rasterScale *= SkScalarSqrt(kMaxBitmapArea / bitmapArea);
     }