Bug 1773384 - Change the type of Downscaler::mScale to MatrixScalesDouble. r=botond

Differential Revision: https://phabricator.services.mozilla.com/D149380

image/Downscaler.cpp

@@ -82,8 +82,9 @@ nsresult Downscaler::BeginFrame(const nsIntSize& aOriginalSize,
                 aHasAlpha);
 
   mOriginalSize = aOriginalSize;
-  mScale = gfxSize(double(mOriginalSize.width) / mTargetSize.width,
-                   double(mOriginalSize.height) / mTargetSize.height);
+  mScale = gfx::MatrixScalesDouble(
+      double(mOriginalSize.width) / mTargetSize.width,
+      double(mOriginalSize.height) / mTargetSize.height);
   mOutputBuffer = aOutputBuffer;
   mHasAlpha = aHasAlpha;
   mFlipVertically = aFlipVertically;
@@ -244,7 +245,7 @@ DownscalerInvalidRect Downscaler::TakeInvalidRect() {
 
   // Compute the original size invalid rect.
   invalidRect.mOriginalSizeRect = invalidRect.mTargetSizeRect;
-  invalidRect.mOriginalSizeRect.ScaleRoundOut(mScale.width, mScale.height);
+  invalidRect.mOriginalSizeRect.ScaleRoundOut(mScale.xScale, mScale.yScale);
 
   return invalidRect;
 }

image/Downscaler.h

@@ -17,6 +17,7 @@
 #include "gfxPoint.h"
 #include "nsRect.h"
 #include "mozilla/gfx/ConvolutionFilter.h"
+#include "mozilla/gfx/Matrix.h"
 
 namespace mozilla {
 namespace image {
@@ -55,7 +56,7 @@ class Downscaler {
   const nsIntSize FrameSize() const {
     return nsIntSize(mFrameRect.Width(), mFrameRect.Height());
   }
-  const gfxSize& Scale() const { return mScale; }
+  const gfx::MatrixScalesDouble& Scale() const { return mScale; }
 
   /**
    * Begins a new frame and reinitializes the Downscaler.
@@ -118,7 +119,7 @@ class Downscaler {
   nsIntSize mOriginalSize;
   nsIntSize mTargetSize;
   nsIntRect mFrameRect;
-  gfxSize mScale;
+  gfx::MatrixScalesDouble mScale;
 
   uint8_t* mOutputBuffer;