fix: use capInsets for stretchable border image

Author: aleclarson

React/Views/RCTBorderDrawing.m

@@ -240,12 +240,11 @@ static CGContextRef RCTUIGraphicsBeginImageContext(CGSize size, CGColorRef backg
     borderInsets.right + MAX(cornerInsets.bottomRight.width, cornerInsets.topRight.width)
   };
 
-  const CGSize size = viewSize;
-//  makeStretchable ? (CGSize){
-//    // 1pt for the middle stretchable area along each axis
-//    edgeInsets.left + 1 + edgeInsets.right,
-//    edgeInsets.top + 1 + edgeInsets.bottom
-//  } : viewSize;
+  const CGSize size = makeStretchable ? (CGSize){
+    // 1pt for the middle stretchable area along each axis
+    edgeInsets.left + 1 + edgeInsets.right,
+    edgeInsets.top + 1 + edgeInsets.bottom
+  } : viewSize;
 
   CGContextRef ctx = RCTUIGraphicsBeginImageContext(size, backgroundColor, hasCornerRadii, drawToEdge);
   const CGRect rect = {.size = size};
@@ -403,25 +402,7 @@ static CGContextRef RCTUIGraphicsBeginImageContext(CGSize size, CGColorRef backg
   UIGraphicsEndImageContext();
 
   if (makeStretchable) {
-    /*
-     * Strechable solid borders is not implemented
-     * image = [image resizableImageWithCapInsets:edgeInsets];
-     **/
-
-//    NSInteger left = edgeInsets.left;
-//    NSInteger top = edgeInsets.top;
-//    NSImage *strechableImage = [[NSImage alloc] initWithSize:viewSize];
-//    [strechableImage lockFocus];
-//    NSSize imgSize = viewSize;
-//
-//
-//    [image drawAtPoint:NSMakePoint(0, 0) fromRect:NSMakeRect(0, 0, left, top) operation:NSCompositeSourceOver fraction:1];
-//    [image drawInRect:NSMakeRect(left, 0, imgSize.width-2*left, top) fromRect:NSMakeRect(left, 0, imgSize.width-2*left, top) operation:NSCompositeSourceOver fraction:1];
-//    [image drawAtPoint:NSMakePoint(0 + imgSize.width - left, 0) fromRect:NSMakeRect(imgSize.width-left, 0, left, top) operation:NSCompositeSourceOver fraction:1];
-//    [strechableImage unlockFocus];
-//
-//    image = strechableImage;
-
+    image.capInsets = edgeInsets;
   }
 
   return image;