Adopting Yoga's YGConfig in RCTShadowView

Reviewed By: javache

Differential Revision: D4932540

fbshipit-source-id: 4a5ff3b34fc635b3291dff9a7c1a603179c90fa7

React/Views/RCTShadowView.h

@@ -35,6 +35,13 @@ typedef void (^RCTApplierBlock)(NSDictionary<NSNumber *, UIView *> *viewRegistry
  */
 @interface RCTShadowView : NSObject <RCTComponent>
 
+/**
+ * Yoga Config which will be used to create `yogaNode` property.
+ * Override in subclass to enable special Yoga features.
+ * Defaults to suitable to current device configuration.
+ */
++ (YGConfigRef)yogaConfig;
+
 /**
  * RCTComponent interface.
  */

React/Views/RCTShadowView.m

@@ -46,6 +46,18 @@ typedef NS_ENUM(unsigned int, meta_prop_t) {
   YGValue _borderMetaProps[META_PROP_COUNT];
 }
 
++ (YGConfigRef)yogaConfig
+{
+  static YGConfigRef yogaConfig;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    yogaConfig = YGConfigNew();
+    // Turnig off pixel rounding.
+    YGConfigSetPointScaleFactor(yogaConfig, 0.0);
+  });
+  return yogaConfig;
+}
+
 @synthesize reactTag = _reactTag;
 
 // YogaNode API
@@ -318,7 +330,6 @@ static void RCTProcessMetaPropsBorder(const YGValue metaProps[META_PROP_COUNT],
 - (instancetype)init
 {
   if ((self = [super init])) {
-
     _frame = CGRectMake(0, 0, YGUndefined, YGUndefined);
 
     for (unsigned int ii = 0; ii < META_PROP_COUNT; ii++) {
@@ -335,7 +346,8 @@ static void RCTProcessMetaPropsBorder(const YGValue metaProps[META_PROP_COUNT],
 
     _reactSubviews = [NSMutableArray array];
 
-    _yogaNode = YGNodeNew();
+    _yogaNode = YGNodeNewWithConfig([[self class] yogaConfig]);
+
     YGNodeSetContext(_yogaNode, (__bridge void *)self);
     YGNodeSetPrintFunc(_yogaNode, RCTPrint);
   }