fix(ios): prevent missing hairlineWidth border strokes at subpixel Y offsets (#58054)

Author: shashikant-panchal

packages/react-native/React/Fabric/Mounting/ComponentViews/View/RCTViewComponentView.mm

@@ -887,7 +887,9 @@ static void RCTAddContourEffectToLayer(
     UIEdgeInsets imageCapInsets = image.capInsets;
     CGRect contentsCenter = CGRect{
         CGPoint{imageCapInsets.left / imageSize.width, imageCapInsets.top / imageSize.height},
-        CGSize{(CGFloat)1.0 / imageSize.width, (CGFloat)1.0 / imageSize.height}};
+        CGSize{
+            MAX(0, (imageSize.width - imageCapInsets.left - imageCapInsets.right) / imageSize.width),
+            MAX(0, (imageSize.height - imageCapInsets.top - imageCapInsets.bottom) / imageSize.height)}};
     layer.contents = (id)image.CGImage;
     layer.contentsScale = image.scale;
 

packages/react-native/React/Views/RCTBorderDrawing.m

@@ -247,12 +247,8 @@ static CGPathRef RCTPathCreateOuterOutline(BOOL drawToEdge, CGRect rect, RCTCorn
 
   const CGSize size = makeStretchable ? (CGSize){
     // 1pt for the middle stretchable area along each axis
-    // we also need to round the edge insets to avoid border bleeding
-    // this is because if the size is decimal, when calculating the unit
-    // rectangle for CALayer.contentsCenter we encounter rounding errors
-    // which causes visual glitches
-    ceil(edgeInsets.left) + 1 + ceil(edgeInsets.right),
-    ceil(edgeInsets.top) + 1 + ceil(edgeInsets.bottom),
+    edgeInsets.left + 1 + edgeInsets.right,
+    edgeInsets.top + 1 + edgeInsets.bottom,
   } : viewSize;
 
   UIGraphicsImageRenderer *const imageRenderer =

packages/react-native/React/Views/RCTView.m

@@ -860,7 +860,10 @@ - (void)displayLayer:(CALayer *)layer
     CGSize size = image.size;
     UIEdgeInsets insets = image.capInsets;
     CGRectMake(
-        insets.left / size.width, insets.top / size.height, (CGFloat)1.0 / size.width, (CGFloat)1.0 / size.height);
+        insets.left / size.width,
+        insets.top / size.height,
+        MAX(0, (size.width - insets.left - insets.right) / size.width),
+        MAX(0, (size.height - insets.top - insets.bottom) / size.height));
   });
 
   layer.contents = (id)image.CGImage;