From 48e346193a477561b137684bd656c8247985bca1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lukas=20W=C3=B6hrl?= <lukas@woehrl.net>
Date: Thu, 26 Jan 2017 13:36:35 -0800
Subject: [PATCH] Fix absolute position if align-item or justify-content is
 center or flex-end

Summary:
Fix #310 (```center```)

additionally fixes if ```flex-end``` is set.
Closes https://github.com/facebook/yoga/pull/349

Reviewed By: dshahidehpour

Differential Revision: D4458528

Pulled By: emilsjolander

fbshipit-source-id: f073c80bfc3ea6675cb95b00283074d10e91a042
---
 ReactCommon/yoga/yoga/Yoga.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/ReactCommon/yoga/yoga/Yoga.c b/ReactCommon/yoga/yoga/Yoga.c
index 51a9287c5..ff944368b 100644
--- a/ReactCommon/yoga/yoga/Yoga.c
+++ b/ReactCommon/yoga/yoga/Yoga.c
@@ -1471,6 +1471,14 @@ static void YGNodeAbsoluteLayoutChild(const YGNodeRef node,
                                                 child->layout.measuredDimensions[dim[mainAxis]] -
                                                 YGNodeTrailingBorder(node, mainAxis) -
                                                 YGNodeTrailingPosition(child, mainAxis, width);
+  } else if (!YGNodeIsLeadingPosDefined(child, mainAxis) && 
+      node->style.justifyContent == YGJustifyCenter) {
+    child->layout.position[leading[mainAxis]] = (node->layout.measuredDimensions[dim[mainAxis]] -
+                                                 child->layout.measuredDimensions[dim[mainAxis]]) / 2.0f;
+  } else if (!YGNodeIsLeadingPosDefined(child, mainAxis) && 
+      node->style.justifyContent == YGJustifyFlexEnd) {
+    child->layout.position[leading[mainAxis]] = (node->layout.measuredDimensions[dim[mainAxis]] -
+                                                 child->layout.measuredDimensions[dim[mainAxis]]);
   }
 
   if (YGNodeIsTrailingPosDefined(child, crossAxis) &&
@@ -1479,6 +1487,14 @@ static void YGNodeAbsoluteLayoutChild(const YGNodeRef node,
                                                  child->layout.measuredDimensions[dim[crossAxis]] -
                                                  YGNodeTrailingBorder(node, crossAxis) -
                                                  YGNodeTrailingPosition(child, crossAxis, width);
+  } else if (!YGNodeIsLeadingPosDefined(child, crossAxis) && 
+    YGNodeAlignItem(node, child) == YGAlignCenter) {
+    child->layout.position[leading[crossAxis]] = (node->layout.measuredDimensions[dim[crossAxis]] -
+                                                  child->layout.measuredDimensions[dim[crossAxis]]) / 2.0f;
+  } else if (!YGNodeIsLeadingPosDefined(child, crossAxis) && 
+    YGNodeAlignItem(node, child) == YGAlignFlexEnd) {
+    child->layout.position[leading[crossAxis]] = (node->layout.measuredDimensions[dim[crossAxis]] -
+                                                  child->layout.measuredDimensions[dim[crossAxis]]);
   }
 }
 
@@ -2785,7 +2801,7 @@ static inline bool YGMeasureModeOldSizeIsUnspecifiedAndStillFits(YGMeasureMode s
                                                                  YGMeasureMode lastSizeMode,
                                                                  float lastComputedSize) {
   return sizeMode == YGMeasureModeAtMost && lastSizeMode == YGMeasureModeUndefined &&
-         size >= lastComputedSize;
+         (size >= lastComputedSize || YGFloatsEqual(size, lastComputedSize));
 }
 
 static inline bool YGMeasureModeNewMeasureSizeIsStricterAndStillValid(YGMeasureMode sizeMode,
@@ -2794,7 +2810,7 @@ static inline bool YGMeasureModeNewMeasureSizeIsStricterAndStillValid(YGMeasureM
                                                                       float lastSize,
                                                                       float lastComputedSize) {
   return lastSizeMode == YGMeasureModeAtMost && sizeMode == YGMeasureModeAtMost &&
-         lastSize > size && lastComputedSize <= size;
+         lastSize > size && (lastComputedSize <= size || YGFloatsEqual(size, lastComputedSize));
 }
 
 bool YGNodeCanUseCachedMeasurement(const YGMeasureMode widthMode,