Merged RCTStaticImage with FB internal version

Summary:
Merged RCTStaticImage with our internal RKStaticImage and ported over logic where assets are loaded at the optimal size and reloaded if the view size changes.

Libraries/Image/RCTImageUtils.m

@@ -0,0 +1,147 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "RCTImageUtils.h"
+
+#import "RCTLog.h"
+
+CGSize RCTTargetSizeForClipRect(CGRect clipRect)
+{
+  return (CGSize){
+    clipRect.size.width + clipRect.origin.x * 2,
+    clipRect.size.height + clipRect.origin.y * 2
+  };
+}
+
+CGRect RCTClipRect(CGSize sourceSize, CGFloat sourceScale,
+                   CGSize destSize, CGFloat destScale,
+                   UIViewContentMode resizeMode)
+{
+  if (CGSizeEqualToSize(destSize, CGSizeZero)) {
+    // Assume we require the largest size available
+    return (CGRect){CGPointZero, sourceSize};
+  }
+
+  // Precompensate for scale
+  CGFloat scale = sourceScale / destScale;
+  sourceSize.width *= scale;
+  sourceSize.height *= scale;
+
+  // Calculate aspect ratios if needed (don't bother if resizeMode == stretch)
+  CGFloat aspect = 0.0, targetAspect = 0.0;
+  if (resizeMode != UIViewContentModeScaleToFill) {
+    aspect = sourceSize.width / sourceSize.height;
+    targetAspect = destSize.width / destSize.height;
+    if (aspect == targetAspect) {
+      resizeMode = UIViewContentModeScaleToFill;
+    }
+  }
+
+  switch (resizeMode) {
+    case UIViewContentModeScaleToFill: // stretch
+
+      sourceSize.width = MIN(destSize.width, sourceSize.width);
+      sourceSize.height = MIN(destSize.height, sourceSize.height);
+      return (CGRect){CGPointZero, sourceSize};
+
+    case UIViewContentModeScaleAspectFit: // contain
+
+      if (targetAspect <= aspect) { // target is taller than content
+
+        sourceSize.width = destSize.width = MIN(sourceSize.width, destSize.width);
+        sourceSize.height = sourceSize.width / aspect;
+
+      } else { // target is wider than content
+
+        sourceSize.height = destSize.height = MIN(sourceSize.height, destSize.height);
+        sourceSize.width = sourceSize.height * aspect;
+      }
+      return (CGRect){CGPointZero, sourceSize};
+
+    case UIViewContentModeScaleAspectFill: // cover
+
+      if (targetAspect <= aspect) { // target is taller than content
+
+        sourceSize.height = destSize.height = MIN(sourceSize.height, destSize.height);
+        sourceSize.width = sourceSize.height * aspect;
+        destSize.width = destSize.height * targetAspect;
+        return (CGRect){{(destSize.width - sourceSize.width) / 2, 0}, sourceSize};
+
+      } else { // target is wider than content
+
+        sourceSize.width = destSize.width = MIN(sourceSize.width, destSize.width);
+        sourceSize.height = sourceSize.width / aspect;
+        destSize.height = destSize.width / targetAspect;
+        return (CGRect){{0, (destSize.height - sourceSize.height) / 2}, sourceSize};
+      }
+
+    default:
+
+      RCTLogError(@"A resizeMode value of %zd is not supported", resizeMode);
+      return (CGRect){CGPointZero, destSize};
+  }
+}
+
+RCT_EXTERN BOOL RCTUpscalingRequired(CGSize sourceSize, CGFloat sourceScale,
+                                     CGSize destSize, CGFloat destScale,
+                                     UIViewContentMode resizeMode)
+{
+  if (CGSizeEqualToSize(destSize, CGSizeZero)) {
+    // Assume we require the largest size available
+    return YES;
+  }
+
+  // Precompensate for scale
+  CGFloat scale = sourceScale / destScale;
+  sourceSize.width *= scale;
+  sourceSize.height *= scale;
+
+  // Calculate aspect ratios if needed (don't bother if resizeMode == stretch)
+  CGFloat aspect = 0.0, targetAspect = 0.0;
+  if (resizeMode != UIViewContentModeScaleToFill) {
+    aspect = sourceSize.width / sourceSize.height;
+    targetAspect = destSize.width / destSize.height;
+    if (aspect == targetAspect) {
+      resizeMode = UIViewContentModeScaleToFill;
+    }
+  }
+
+  switch (resizeMode) {
+    case UIViewContentModeScaleToFill: // stretch
+
+      return destSize.width > sourceSize.width || destSize.height > sourceSize.height;
+
+    case UIViewContentModeScaleAspectFit: // contain
+
+      if (targetAspect <= aspect) { // target is taller than content
+
+        return destSize.width > sourceSize.width;
+
+      } else { // target is wider than content
+
+        return destSize.height > sourceSize.height;
+      }
+
+    case UIViewContentModeScaleAspectFill: // cover
+
+      if (targetAspect <= aspect) { // target is taller than content
+
+        return destSize.height > sourceSize.height;
+
+      } else { // target is wider than content
+
+        return destSize.width > sourceSize.width;
+      }
+
+    default:
+
+      RCTLogError(@"A resizeMode value of %zd is not supported", resizeMode);
+      return NO;
+  }
+}