[ASImageNode]fix incorrect backing size calculation

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## master
 * Add your own contributions to the next release on the line below this with your name.
+- [ASImageNode] Fix incorrect backing size calculation. [Junjie Lu](https://github.com/junjielu). [#1189](https://github.com/TextureGroup/Texture/pull/1189)
 - [ASDisplayNode.m] Make sure node is loaded before enter visible. [Max Wang](https://github.com/wsdwsd0829). [#886](https://github.com/TextureGroup/Texture/pull/886)
 - [ASTextNode2] Add improved support for all line-break modes in experimental text node. [Kevin Smith](https://github.com/wiseoldduck). [#1150](https://github.com/TextureGroup/Texture/pull/1150)
 - [ASExperimentalFeatures.m] Fix mismatch name in experimental features. [Max Wang](https://github.com/wsdwsd0829). [#1159](https://github.com/TextureGroup/Texture/pull/1159)

Source/Private/ASImageNode+CGExtras.m

@@ -53,26 +53,27 @@ void ASCroppedImageBackingSizeAndDrawRectInBounds(CGSize sourceImageSize,
   // Per the API contract as commented in the header, we will adjust input parameters (destinationWidth, destinationHeight) to ensure that the image is not upscaled on the CPU.
   CGFloat boundsAspectRatio = (CGFloat)destinationWidth / (CGFloat)destinationHeight;
 
-  CGSize scaledSizeForImage = sourceImageSize;
+  CGSize minimumDestinationSize = sourceImageSize;
   BOOL cropToRectDimensions = !CGRectIsEmpty(cropRect);
 
+  // Given image size and container ratio, calculate minimum container size for the image under different contentMode
   if (cropToRectDimensions) {
-    scaledSizeForImage = CGSizeMake(boundsSize.width / cropRect.size.width, boundsSize.height / cropRect.size.height);
+    minimumDestinationSize = CGSizeMake(boundsSize.width / cropRect.size.width, boundsSize.height / cropRect.size.height);
   } else {
     if (contentMode == UIViewContentModeScaleAspectFill)
-      scaledSizeForImage = _ASSizeFillWithAspectRatio(boundsAspectRatio, sourceImageSize);
+      minimumDestinationSize = _ASSizeFitWithAspectRatio(boundsAspectRatio, sourceImageSize);
     else if (contentMode == UIViewContentModeScaleAspectFit)
-      scaledSizeForImage = _ASSizeFitWithAspectRatio(boundsAspectRatio, sourceImageSize);
+      minimumDestinationSize = _ASSizeFillWithAspectRatio(boundsAspectRatio, sourceImageSize);
   }
 
   // If fitting the desired aspect ratio to the image size actually results in a larger buffer, use the input values.
   // However, if there is a pixel savings (e.g. we would have to upscale the image), override the function arguments.
   if (CGSizeEqualToSize(CGSizeZero, forcedSize) == NO) {
     destinationWidth = (size_t)round(forcedSize.width);
     destinationHeight = (size_t)round(forcedSize.height);
-  } else if (forceUpscaling == NO && (scaledSizeForImage.width * scaledSizeForImage.height) < (destinationWidth * destinationHeight)) {
-    destinationWidth = (size_t)round(scaledSizeForImage.width);
-    destinationHeight = (size_t)round(scaledSizeForImage.height);
+  } else if (forceUpscaling == NO && (minimumDestinationSize.width * minimumDestinationSize.height) < (destinationWidth * destinationHeight)) {
+    destinationWidth = (size_t)round(minimumDestinationSize.width);
+    destinationHeight = (size_t)round(minimumDestinationSize.height);
     if (destinationWidth == 0 || destinationHeight == 0) {
       *outBackingSize = CGSizeZero;
       *outDrawRect = CGRectZero;
@@ -82,39 +83,39 @@ void ASCroppedImageBackingSizeAndDrawRectInBounds(CGSize sourceImageSize,
 
   // Figure out the scaled size within the destination bounds.
   CGFloat sourceImageAspectRatio = sourceImageSize.width / sourceImageSize.height;
-  CGSize scaledSizeForDestination = CGSizeMake(destinationWidth, destinationHeight);
+  CGSize scaledSizeForImage = CGSizeMake(destinationWidth, destinationHeight);
 
   if (cropToRectDimensions) {
-    scaledSizeForDestination = CGSizeMake(boundsSize.width / cropRect.size.width, boundsSize.height / cropRect.size.height);
+    scaledSizeForImage = CGSizeMake(boundsSize.width / cropRect.size.width, boundsSize.height / cropRect.size.height);
   } else {
     if (contentMode == UIViewContentModeScaleAspectFill)
-      scaledSizeForDestination = _ASSizeFillWithAspectRatio(sourceImageAspectRatio, scaledSizeForDestination);
+      scaledSizeForImage = _ASSizeFillWithAspectRatio(sourceImageAspectRatio, scaledSizeForImage);
     else if (contentMode == UIViewContentModeScaleAspectFit)
-      scaledSizeForDestination = _ASSizeFitWithAspectRatio(sourceImageAspectRatio, scaledSizeForDestination);
+      scaledSizeForImage = _ASSizeFitWithAspectRatio(sourceImageAspectRatio, scaledSizeForImage);
   }
 
   // Figure out the rectangle into which to draw the image.
   CGRect drawRect = CGRectZero;
   if (cropToRectDimensions) {
-    drawRect = CGRectMake(-cropRect.origin.x * scaledSizeForDestination.width,
-                          -cropRect.origin.y * scaledSizeForDestination.height,
-                          scaledSizeForDestination.width,
-                          scaledSizeForDestination.height);
+    drawRect = CGRectMake(-cropRect.origin.x * scaledSizeForImage.width,
+                          -cropRect.origin.y * scaledSizeForImage.height,
+                          scaledSizeForImage.width,
+                          scaledSizeForImage.height);
   } else {
     // We want to obey the origin of cropRect in aspect-fill mode.
     if (contentMode == UIViewContentModeScaleAspectFill) {
-      drawRect = CGRectMake(((destinationWidth - scaledSizeForDestination.width) * cropRect.origin.x),
-                            ((destinationHeight - scaledSizeForDestination.height) * cropRect.origin.y),
-                            scaledSizeForDestination.width,
-                            scaledSizeForDestination.height);
+      drawRect = CGRectMake(((destinationWidth - scaledSizeForImage.width) * cropRect.origin.x),
+                            ((destinationHeight - scaledSizeForImage.height) * cropRect.origin.y),
+                            scaledSizeForImage.width,
+                            scaledSizeForImage.height);
 
     }
     // And otherwise just center it.
     else {
-      drawRect = CGRectMake(((destinationWidth - scaledSizeForDestination.width) / 2.0),
-                            ((destinationHeight - scaledSizeForDestination.height) / 2.0),
-                            scaledSizeForDestination.width,
-                            scaledSizeForDestination.height);
+      drawRect = CGRectMake(((destinationWidth - scaledSizeForImage.width) / 2.0),
+                            ((destinationHeight - scaledSizeForImage.height) / 2.0),
+                            scaledSizeForImage.width,
+                            scaledSizeForImage.height);
     }
   }