yoga/Yoga.c

@@ -98,6 +98,7 @@ typedef struct YGNode {
   YGNodeRef parent;
   YGNodeListRef children;
   bool isDirty;
+  bool isVisible;
 
   struct YGNode *nextChild;
 
@@ -190,6 +191,7 @@ static void YGNodeInit(const YGNodeRef node) {
   node->children = NULL;
   node->hasNewLayout = true;
   node->isDirty = false;
+  node->isVisible = true;
 
   node->style.flex = YGUndefined;
   node->style.flexGrow = YGUndefined;
@@ -348,6 +350,22 @@ bool YGNodeIsDirty(const YGNodeRef node) {
   return node->isDirty;
 }
 
+void YGNodeHide(const YGNodeRef node) {
+  node->isVisible = false;
+  node->isDirty = false; /* See https://github.com/facebook/css-layout/issues/241 */
+  YGNodeMarkDirty(node);
+}
+
+void YGNodeShow(const YGNodeRef node) {
+  node->isVisible = true;
+  node->isDirty = false; /* See https://github.com/facebook/css-layout/issues/241 */
+  YGNodeMarkDirty(node);
+}
+
+bool YGNodeIsVisible(const YGNodeRef node) {
+  return node->isVisible;
+}
+
 void YGNodeCopyStyle(const YGNodeRef dstNode, const YGNodeRef srcNode) {
   if (memcmp(&dstNode->style, &srcNode->style, sizeof(YGStyle)) != 0) {
     memcpy(&dstNode->style, &srcNode->style, sizeof(YGStyle));
@@ -1531,6 +1549,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
   // STEP 3: DETERMINE FLEX BASIS FOR EACH ITEM
   for (uint32_t i = 0; i < childCount; i++) {
     const YGNodeRef child = YGNodeListGet(node->children, i);
+    if (NULL != child && false == YGNodeIsVisible(child)) {
+      continue;
+    }
 
     if (performLayout) {
       // Set the initial position (relative to the parent).
@@ -1605,6 +1626,10 @@ static void YGNodelayoutImpl(const YGNodeRef node,
     // Add items to the current line until it's full or we run out of items.
     for (uint32_t i = startOfLineIndex; i < childCount; i++, endOfLineIndex++) {
       const YGNodeRef child = YGNodeListGet(node->children, i);
+      if (NULL != child && false == YGNodeIsVisible(child)) {
+        continue;
+      }
+
       child->lineIndex = lineCount;
 
       if (child->style.positionType != YGPositionTypeAbsolute) {
@@ -1939,6 +1964,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
 
     for (uint32_t i = startOfLineIndex; i < endOfLineIndex; i++) {
       const YGNodeRef child = YGNodeListGet(node->children, i);
+      if (NULL != child && false == YGNodeIsVisible(child)) {
+        continue;
+      }
 
       if (child->style.positionType == YGPositionTypeAbsolute &&
           YGNodeIsLeadingPosDefined(child, mainAxis)) {
@@ -2011,6 +2039,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
     if (performLayout) {
       for (uint32_t i = startOfLineIndex; i < endOfLineIndex; i++) {
         const YGNodeRef child = YGNodeListGet(node->children, i);
+        if (NULL != child && false == YGNodeIsVisible(child)) {
+          continue;
+        }
 
         if (child->style.positionType == YGPositionTypeAbsolute) {
           // If the child is absolutely positioned and has a
@@ -2136,6 +2167,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
       float lineHeight = 0;
       for (ii = startIndex; ii < childCount; ii++) {
         const YGNodeRef child = YGNodeListGet(node->children, ii);
+        if (NULL != child && false == YGNodeIsVisible(child)) {
+          continue;
+        }
 
         if (child->style.positionType == YGPositionTypeRelative) {
           if (child->lineIndex != i) {
@@ -2155,6 +2189,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
       if (performLayout) {
         for (ii = startIndex; ii < endIndex; ii++) {
           const YGNodeRef child = YGNodeListGet(node->children, ii);
+          if (NULL != child && false == YGNodeIsVisible(child)) {
+            continue;
+          }
 
           if (child->style.positionType == YGPositionTypeRelative) {
             switch (YGNodeAlignItem(node, child)) {
@@ -2246,6 +2283,9 @@ static void YGNodelayoutImpl(const YGNodeRef node,
     if (needsMainTrailingPos || needsCrossTrailingPos) {
       for (uint32_t i = 0; i < childCount; i++) {
         const YGNodeRef child = YGNodeListGet(node->children, i);
+        if (NULL != child && false == YGNodeIsVisible(child)) {
+          continue;
+        }
 
         if (needsMainTrailingPos) {
           YGNodeSetChildTrailingPosition(node, child, mainAxis);

yoga/Yoga.h

@@ -80,6 +80,10 @@ WIN_EXPORT void YGNodeCalculateLayout(const YGNodeRef node,
 WIN_EXPORT void YGNodeMarkDirty(const YGNodeRef node);
 WIN_EXPORT bool YGNodeIsDirty(const YGNodeRef node);
 
+WIN_EXPORT void YGNodeHide(const YGNodeRef node);
+WIN_EXPORT void YGNodeShow(const YGNodeRef node);
+WIN_EXPORT bool YGNodeIsVisible(const YGNodeRef node);
+
 WIN_EXPORT void YGNodePrint(const YGNodeRef node, const YGPrintOptions options);
 
 WIN_EXPORT bool YGValueIsUndefined(const float value);