SkPDF: Add SkPDFCanvas to intercept some draw calls

src/pdf/SkPDFCanvas.cpp

Index: src/pdf/SkPDFCanvas.cpp
diff --git a/src/pdf/SkPDFCanvas.cpp b/src/pdf/SkPDFCanvas.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..de3dc93528cb8783653bcfc2e5564847d39da94c
--- /dev/null
+++ b/src/pdf/SkPDFCanvas.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkNinePatchIter.h"
+#include "SkPDFCanvas.h"
+#include "SkPDFDevice.h"
+
+SkPDFCanvas::SkPDFCanvas(const sk_sp<SkPDFDevice>& dev)
+    : SkCanvas(dev.get()) {}
+
+SkPDFCanvas::~SkPDFCanvas() {}
+
+void SkPDFCanvas::onDrawBitmapNine(const SkBitmap& bitmap,
+                                   const SkIRect& center,
+                                   const SkRect& dst,
+                                   const SkPaint* paint) {
+    SkNinePatchIter iter(bitmap.width(), bitmap.height(), center, dst);
+    SkRect srcR, dstR;
+    while (iter.next(&srcR, &dstR)) {
+        this->drawBitmapRect(bitmap, srcR, dstR, paint);
+    }
+}
+
+void SkPDFCanvas::onDrawImageNine(const SkImage* image,
+                                  const SkIRect& center,
+                                  const SkRect& dst,
+                     const SkPaint* paint) {
+    SkNinePatchIter iter(image->width(), image->height(), center, dst);
+    SkRect srcR, dstR;
+    while (iter.next(&srcR, &dstR)) {
+        this->drawImageRect(image, srcR, dstR, paint);
+    }
+}
+
+void SkPDFCanvas::onDrawImageRect(const SkImage* image,
+                                  const SkRect* srcPtr,
+                                  const SkRect& dst,
+                                  const SkPaint* paint,
+                                  SkCanvas::SrcRectConstraint constraint) {
+    SkRect bounds = SkRect::Make(image->bounds());
+    SkRect src = srcPtr ? *srcPtr : bounds;
+    SkAutoCanvasRestore autoCanvasRestore(this, true);
+    if (src != bounds) {
+        this->clipRect(dst);
+    }
+    this->concat(SkMatrix::MakeRectToRect(src, dst,
+                                 SkMatrix::kFill_ScaleToFit));
+    this->drawImage(image, 0, 0, paint);
+}
+
+void SkPDFCanvas::onDrawBitmapRect(const SkBitmap& bitmap,
+                                   const SkRect* srcPtr,
+                                   const SkRect& dst,
+                                   const SkPaint* paint,
+                                   SkCanvas::SrcRectConstraint constraint) {
+    SkRect bounds = SkRect::Make(bitmap.bounds());
+    SkRect src = srcPtr ? *srcPtr : bounds;
+    SkAutoCanvasRestore autoCanvasRestore(this, true);
+    if (src != bounds) {
+        this->clipRect(dst);
+    }
+    this->concat(SkMatrix::MakeRectToRect(src, dst,
+                                 SkMatrix::kFill_ScaleToFit));
+    this->drawBitmap(bitmap, 0, 0, paint);
+}