Fix margin auto for start and end values

Summary: Margin auto was not handling start/end margins correctly

Reviewed By: astreet

Differential Revision: D4627339

fbshipit-source-id: eebf64e79a34331e79cffcfa3662d4938fbd6c13

csharp/tests/Facebook.Yoga/YGMarginTest.cs

@@ -913,6 +913,118 @@ namespace Facebook.Yoga
             Assert.AreEqual(50f, root_child1.LayoutHeight);
         }
 
+        [Test]
+        public void Test_margin_auto_start_and_end_column()
+        {
+            YogaNode root = new YogaNode();
+            root.FlexDirection = YogaFlexDirection.Row;
+            root.AlignItems = YogaAlign.Center;
+            root.Width = 200;
+            root.Height = 200;
+
+            YogaNode root_child0 = new YogaNode();
+            root_child0.MarginStart = YogaValue.Auto();
+            root_child0.MarginEnd = YogaValue.Auto();
+            root_child0.Width = 50;
+            root_child0.Height = 50;
+            root.Insert(0, root_child0);
+
+            YogaNode root_child1 = new YogaNode();
+            root_child1.Width = 50;
+            root_child1.Height = 50;
+            root.Insert(1, root_child1);
+            root.StyleDirection = YogaDirection.LTR;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(200f, root.LayoutWidth);
+            Assert.AreEqual(200f, root.LayoutHeight);
+
+            Assert.AreEqual(50f, root_child0.LayoutX);
+            Assert.AreEqual(75f, root_child0.LayoutY);
+            Assert.AreEqual(50f, root_child0.LayoutWidth);
+            Assert.AreEqual(50f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(150f, root_child1.LayoutX);
+            Assert.AreEqual(75f, root_child1.LayoutY);
+            Assert.AreEqual(50f, root_child1.LayoutWidth);
+            Assert.AreEqual(50f, root_child1.LayoutHeight);
+
+            root.StyleDirection = YogaDirection.RTL;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(200f, root.LayoutWidth);
+            Assert.AreEqual(200f, root.LayoutHeight);
+
+            Assert.AreEqual(100f, root_child0.LayoutX);
+            Assert.AreEqual(75f, root_child0.LayoutY);
+            Assert.AreEqual(50f, root_child0.LayoutWidth);
+            Assert.AreEqual(50f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child1.LayoutX);
+            Assert.AreEqual(75f, root_child1.LayoutY);
+            Assert.AreEqual(50f, root_child1.LayoutWidth);
+            Assert.AreEqual(50f, root_child1.LayoutHeight);
+        }
+
+        [Test]
+        public void Test_margin_auto_start_and_end()
+        {
+            YogaNode root = new YogaNode();
+            root.Width = 200;
+            root.Height = 200;
+
+            YogaNode root_child0 = new YogaNode();
+            root_child0.MarginStart = YogaValue.Auto();
+            root_child0.MarginEnd = YogaValue.Auto();
+            root_child0.Width = 50;
+            root_child0.Height = 50;
+            root.Insert(0, root_child0);
+
+            YogaNode root_child1 = new YogaNode();
+            root_child1.Width = 50;
+            root_child1.Height = 50;
+            root.Insert(1, root_child1);
+            root.StyleDirection = YogaDirection.LTR;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(200f, root.LayoutWidth);
+            Assert.AreEqual(200f, root.LayoutHeight);
+
+            Assert.AreEqual(75f, root_child0.LayoutX);
+            Assert.AreEqual(0f, root_child0.LayoutY);
+            Assert.AreEqual(50f, root_child0.LayoutWidth);
+            Assert.AreEqual(50f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(0f, root_child1.LayoutX);
+            Assert.AreEqual(50f, root_child1.LayoutY);
+            Assert.AreEqual(50f, root_child1.LayoutWidth);
+            Assert.AreEqual(50f, root_child1.LayoutHeight);
+
+            root.StyleDirection = YogaDirection.RTL;
+            root.CalculateLayout();
+
+            Assert.AreEqual(0f, root.LayoutX);
+            Assert.AreEqual(0f, root.LayoutY);
+            Assert.AreEqual(200f, root.LayoutWidth);
+            Assert.AreEqual(200f, root.LayoutHeight);
+
+            Assert.AreEqual(75f, root_child0.LayoutX);
+            Assert.AreEqual(0f, root_child0.LayoutY);
+            Assert.AreEqual(50f, root_child0.LayoutWidth);
+            Assert.AreEqual(50f, root_child0.LayoutHeight);
+
+            Assert.AreEqual(150f, root_child1.LayoutX);
+            Assert.AreEqual(50f, root_child1.LayoutY);
+            Assert.AreEqual(50f, root_child1.LayoutWidth);
+            Assert.AreEqual(50f, root_child1.LayoutHeight);
+        }
+
         [Test]
         public void Test_margin_auto_left_and_right_column_and_center()
         {

gentest/fixtures/YGMarginTest.html

@@ -82,6 +82,16 @@
   <div style="width: 50px; height: 50px;"></div>
 </div>
 
+<div id="margin_auto_start_and_end_column" style="width: 200px; height: 200px; align-items: center; flex-direction: row;">
+  <div style="width: 50px; height: 50px; margin-start: auto; margin-end: auto;"></div>
+  <div style="width: 50px; height: 50px;"></div>
+</div>
+
+<div id="margin_auto_start_and_end" style="width: 200px; height: 200px; ">
+  <div style="width: 50px; height: 50px; margin-start: auto; margin-end: auto;"></div>
+  <div style="width: 50px; height: 50px;"></div>
+</div>
+
 <div id="margin_auto_left_and_right_column_and_center" style="width: 200px; height: 200px; align-items: center;">
   <div style="width: 50px; height: 50px; margin-left:auto; margin-right:auto;"></div>
   <div style="width: 50px; height: 50px;"></div>

java/tests/com/facebook/yoga/YGMarginTest.java

@@ -894,6 +894,116 @@ public class YGMarginTest {
     assertEquals(50f, root_child1.getLayoutHeight(), 0.0f);
   }
 
+  @Test
+  public void test_margin_auto_start_and_end_column() {
+    final YogaNode root = new YogaNode();
+    root.setFlexDirection(YogaFlexDirection.ROW);
+    root.setAlignItems(YogaAlign.CENTER);
+    root.setWidth(200f);
+    root.setHeight(200f);
+
+    final YogaNode root_child0 = new YogaNode();
+    root_child0.setMarginAuto(YogaEdge.START);
+    root_child0.setMarginAuto(YogaEdge.END);
+    root_child0.setWidth(50f);
+    root_child0.setHeight(50f);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child1 = new YogaNode();
+    root_child1.setWidth(50f);
+    root_child1.setHeight(50f);
+    root.addChildAt(root_child1, 1);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(50f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(75f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(150f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(75f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutHeight(), 0.0f);
+
+    root.setDirection(YogaDirection.RTL);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(100f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(75f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(75f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutHeight(), 0.0f);
+  }
+
+  @Test
+  public void test_margin_auto_start_and_end() {
+    final YogaNode root = new YogaNode();
+    root.setWidth(200f);
+    root.setHeight(200f);
+
+    final YogaNode root_child0 = new YogaNode();
+    root_child0.setMarginAuto(YogaEdge.START);
+    root_child0.setMarginAuto(YogaEdge.END);
+    root_child0.setWidth(50f);
+    root_child0.setHeight(50f);
+    root.addChildAt(root_child0, 0);
+
+    final YogaNode root_child1 = new YogaNode();
+    root_child1.setWidth(50f);
+    root_child1.setHeight(50f);
+    root.addChildAt(root_child1, 1);
+    root.setDirection(YogaDirection.LTR);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(75f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(0f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutHeight(), 0.0f);
+
+    root.setDirection(YogaDirection.RTL);
+    root.calculateLayout(YogaConstants.UNDEFINED, YogaConstants.UNDEFINED);
+
+    assertEquals(0f, root.getLayoutX(), 0.0f);
+    assertEquals(0f, root.getLayoutY(), 0.0f);
+    assertEquals(200f, root.getLayoutWidth(), 0.0f);
+    assertEquals(200f, root.getLayoutHeight(), 0.0f);
+
+    assertEquals(75f, root_child0.getLayoutX(), 0.0f);
+    assertEquals(0f, root_child0.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child0.getLayoutHeight(), 0.0f);
+
+    assertEquals(150f, root_child1.getLayoutX(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutY(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutWidth(), 0.0f);
+    assertEquals(50f, root_child1.getLayoutHeight(), 0.0f);
+  }
+
   @Test
   public void test_margin_auto_left_and_right_column_and_center() {
     final YogaNode root = new YogaNode();

javascript/tests/Facebook.Yoga/YGMarginTest.js

@@ -925,6 +925,120 @@ it("margin_auto_left_and_right", function () {
     }
   }
 });
+it("margin_auto_start_and_end_column", function () {
+  try {
+    var root = Yoga.Node.create();
+    root.setFlexDirection(Yoga.FLEX_DIRECTION_ROW);
+    root.setAlignItems(Yoga.ALIGN_CENTER);
+    root.setWidth(200);
+    root.setHeight(200);
+
+    var root_child0 = Yoga.Node.create();
+    root_child0.setMargin(Yoga.EDGE_START, "auto");
+    root_child0.setMargin(Yoga.EDGE_END, "auto");
+    root_child0.setWidth(50);
+    root_child0.setHeight(50);
+    root.insertChild(root_child0, 0);
+
+    var root_child1 = Yoga.Node.create();
+    root_child1.setWidth(50);
+    root_child1.setHeight(50);
+    root.insertChild(root_child1, 1);
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_LTR);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(200 === root.getComputedWidth(), "200 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(200 === root.getComputedHeight(), "200 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(50 === root_child0.getComputedLeft(), "50 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(75 === root_child0.getComputedTop(), "75 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(50 === root_child0.getComputedWidth(), "50 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(50 === root_child0.getComputedHeight(), "50 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(150 === root_child1.getComputedLeft(), "150 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(75 === root_child1.getComputedTop(), "75 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(50 === root_child1.getComputedWidth(), "50 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(50 === root_child1.getComputedHeight(), "50 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_RTL);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(200 === root.getComputedWidth(), "200 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(200 === root.getComputedHeight(), "200 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(100 === root_child0.getComputedLeft(), "100 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(75 === root_child0.getComputedTop(), "75 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(50 === root_child0.getComputedWidth(), "50 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(50 === root_child0.getComputedHeight(), "50 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(0 === root_child1.getComputedLeft(), "0 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(75 === root_child1.getComputedTop(), "75 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(50 === root_child1.getComputedWidth(), "50 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(50 === root_child1.getComputedHeight(), "50 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+  } finally {
+    if (typeof root !== "undefined") {
+      root.freeRecursive();
+    }
+  }
+});
+it("margin_auto_start_and_end", function () {
+  try {
+    var root = Yoga.Node.create();
+    root.setWidth(200);
+    root.setHeight(200);
+
+    var root_child0 = Yoga.Node.create();
+    root_child0.setMargin(Yoga.EDGE_START, "auto");
+    root_child0.setMargin(Yoga.EDGE_END, "auto");
+    root_child0.setWidth(50);
+    root_child0.setHeight(50);
+    root.insertChild(root_child0, 0);
+
+    var root_child1 = Yoga.Node.create();
+    root_child1.setWidth(50);
+    root_child1.setHeight(50);
+    root.insertChild(root_child1, 1);
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_LTR);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(200 === root.getComputedWidth(), "200 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(200 === root.getComputedHeight(), "200 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(75 === root_child0.getComputedLeft(), "75 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(0 === root_child0.getComputedTop(), "0 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(50 === root_child0.getComputedWidth(), "50 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(50 === root_child0.getComputedHeight(), "50 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(0 === root_child1.getComputedLeft(), "0 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(50 === root_child1.getComputedTop(), "50 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(50 === root_child1.getComputedWidth(), "50 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(50 === root_child1.getComputedHeight(), "50 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+
+    root.calculateLayout(Yoga.UNDEFINED, Yoga.UNDEFINED, Yoga.DIRECTION_RTL);
+
+    console.assert(0 === root.getComputedLeft(), "0 === root.getComputedLeft() (" + root.getComputedLeft() + ")");
+    console.assert(0 === root.getComputedTop(), "0 === root.getComputedTop() (" + root.getComputedTop() + ")");
+    console.assert(200 === root.getComputedWidth(), "200 === root.getComputedWidth() (" + root.getComputedWidth() + ")");
+    console.assert(200 === root.getComputedHeight(), "200 === root.getComputedHeight() (" + root.getComputedHeight() + ")");
+
+    console.assert(75 === root_child0.getComputedLeft(), "75 === root_child0.getComputedLeft() (" + root_child0.getComputedLeft() + ")");
+    console.assert(0 === root_child0.getComputedTop(), "0 === root_child0.getComputedTop() (" + root_child0.getComputedTop() + ")");
+    console.assert(50 === root_child0.getComputedWidth(), "50 === root_child0.getComputedWidth() (" + root_child0.getComputedWidth() + ")");
+    console.assert(50 === root_child0.getComputedHeight(), "50 === root_child0.getComputedHeight() (" + root_child0.getComputedHeight() + ")");
+
+    console.assert(150 === root_child1.getComputedLeft(), "150 === root_child1.getComputedLeft() (" + root_child1.getComputedLeft() + ")");
+    console.assert(50 === root_child1.getComputedTop(), "50 === root_child1.getComputedTop() (" + root_child1.getComputedTop() + ")");
+    console.assert(50 === root_child1.getComputedWidth(), "50 === root_child1.getComputedWidth() (" + root_child1.getComputedWidth() + ")");
+    console.assert(50 === root_child1.getComputedHeight(), "50 === root_child1.getComputedHeight() (" + root_child1.getComputedHeight() + ")");
+  } finally {
+    if (typeof root !== "undefined") {
+      root.freeRecursive();
+    }
+  }
+});
 it("margin_auto_left_and_right_column_and_center", function () {
   try {
     var root = Yoga.Node.create();

tests/YGMarginTest.cpp

@@ -872,6 +872,114 @@ TEST(YogaTest, margin_auto_left_and_right) {
   YGNodeFreeRecursive(root);
 }
 
+TEST(YogaTest, margin_auto_start_and_end_column) {
+  const YGNodeRef root = YGNodeNew();
+  YGNodeStyleSetFlexDirection(root, YGFlexDirectionRow);
+  YGNodeStyleSetAlignItems(root, YGAlignCenter);
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 200);
+
+  const YGNodeRef root_child0 = YGNodeNew();
+  YGNodeStyleSetMarginAuto(root_child0, YGEdgeStart);
+  YGNodeStyleSetMarginAuto(root_child0, YGEdgeEnd);
+  YGNodeStyleSetWidth(root_child0, 50);
+  YGNodeStyleSetHeight(root_child0, 50);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  const YGNodeRef root_child1 = YGNodeNew();
+  YGNodeStyleSetWidth(root_child1, 50);
+  YGNodeStyleSetHeight(root_child1, 50);
+  YGNodeInsertChild(root, root_child1, 1);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(75, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(150, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(75, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(100, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(75, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(75, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeFreeRecursive(root);
+}
+
+TEST(YogaTest, margin_auto_start_and_end) {
+  const YGNodeRef root = YGNodeNew();
+  YGNodeStyleSetWidth(root, 200);
+  YGNodeStyleSetHeight(root, 200);
+
+  const YGNodeRef root_child0 = YGNodeNew();
+  YGNodeStyleSetMarginAuto(root_child0, YGEdgeStart);
+  YGNodeStyleSetMarginAuto(root_child0, YGEdgeEnd);
+  YGNodeStyleSetWidth(root_child0, 50);
+  YGNodeStyleSetHeight(root_child0, 50);
+  YGNodeInsertChild(root, root_child0, 0);
+
+  const YGNodeRef root_child1 = YGNodeNew();
+  YGNodeStyleSetWidth(root_child1, 50);
+  YGNodeStyleSetHeight(root_child1, 50);
+  YGNodeInsertChild(root, root_child1, 1);
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(75, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionRTL);
+
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetLeft(root));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetWidth(root));
+  ASSERT_FLOAT_EQ(200, YGNodeLayoutGetHeight(root));
+
+  ASSERT_FLOAT_EQ(75, YGNodeLayoutGetLeft(root_child0));
+  ASSERT_FLOAT_EQ(0, YGNodeLayoutGetTop(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child0));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child0));
+
+  ASSERT_FLOAT_EQ(150, YGNodeLayoutGetLeft(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetTop(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetWidth(root_child1));
+  ASSERT_FLOAT_EQ(50, YGNodeLayoutGetHeight(root_child1));
+
+  YGNodeFreeRecursive(root);
+}
+
 TEST(YogaTest, margin_auto_left_and_right_column_and_center) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignCenter);

yoga/Yoga.c

@@ -1247,6 +1247,22 @@ static float YGNodeBoundAxisWithinMinAndMax(const YGNodeRef node,
   return boundValue;
 }
 
+static inline YGValue *YGMarginLeadingValue(const YGNodeRef node, const YGFlexDirection axis) {
+  if (YGFlexDirectionIsRow(axis) && node->style.margin[YGEdgeStart].unit != YGUnitUndefined) {
+    return &node->style.margin[YGEdgeStart];
+  } else {
+    return &node->style.margin[leading[axis]];
+  }
+}
+
+static inline YGValue *YGMarginTrailingValue(const YGNodeRef node, const YGFlexDirection axis) {
+  if (YGFlexDirectionIsRow(axis) && node->style.margin[YGEdgeEnd].unit != YGUnitUndefined) {
+    return &node->style.margin[YGEdgeEnd];
+  } else {
+    return &node->style.margin[trailing[axis]];
+  }
+}
+
 // Like YGNodeBoundAxisWithinMinAndMax but also ensures that the value doesn't go
 // below the
 // padding and border amount.
@@ -2442,10 +2458,10 @@ static void YGNodelayoutImpl(const YGNodeRef node,
     for (uint32_t i = startOfLineIndex; i < endOfLineIndex; i++) {
       const YGNodeRef child = YGNodeListGet(node->children, i);
       if (child->style.positionType == YGPositionTypeRelative) {
-        if (child->style.margin[leading[mainAxis]].unit == YGUnitAuto) {
+        if (YGMarginLeadingValue(child, mainAxis)->unit == YGUnitAuto) {
           numberOfAutoMarginsOnCurrentLine++;
         }
-        if (child->style.margin[trailing[mainAxis]].unit == YGUnitAuto) {
+        if (YGMarginTrailingValue(child, mainAxis)->unit == YGUnitAuto) {
           numberOfAutoMarginsOnCurrentLine++;
         }
       }
@@ -2500,7 +2516,7 @@ static void YGNodelayoutImpl(const YGNodeRef node,
         // We need to do that only for relative elements. Absolute elements
         // do not take part in that phase.
         if (child->style.positionType == YGPositionTypeRelative) {
-          if (child->style.margin[leading[mainAxis]].unit == YGUnitAuto) {
+          if (YGMarginLeadingValue(child, mainAxis)->unit == YGUnitAuto) {
             mainDim += remainingFreeSpace / numberOfAutoMarginsOnCurrentLine;
           }
 
@@ -2508,7 +2524,7 @@ static void YGNodelayoutImpl(const YGNodeRef node,
             child->layout.position[pos[mainAxis]] += mainDim;
           }
 
-          if (child->style.margin[trailing[mainAxis]].unit == YGUnitAuto) {
+          if (YGMarginTrailingValue(child, mainAxis)->unit == YGUnitAuto) {
             mainDim += remainingFreeSpace / numberOfAutoMarginsOnCurrentLine;
           }
 
@@ -2601,8 +2617,8 @@ static void YGNodelayoutImpl(const YGNodeRef node,
           // forcing the cross-axis size to be the computed cross size for the
           // current line.
           if (alignItem == YGAlignStretch &&
-              child->style.margin[leading[crossAxis]].unit != YGUnitAuto &&
+              YGMarginLeadingValue(child, crossAxis)->unit != YGUnitAuto &&
-              child->style.margin[trailing[crossAxis]].unit != YGUnitAuto) {
+              YGMarginTrailingValue(child, crossAxis)->unit != YGUnitAuto) {
             // If the child defines a definite size for its cross axis, there's
             // no need to stretch.
             if (!YGNodeIsStyleDimDefined(child, crossAxis, availableInnerCrossDim)) {
@@ -2650,12 +2666,12 @@ static void YGNodelayoutImpl(const YGNodeRef node,
             const float remainingCrossDim =
                 containerCrossAxis - YGNodeDimWithMargin(child, crossAxis, availableInnerWidth);
 
-            if (child->style.margin[leading[crossAxis]].unit == YGUnitAuto &&
+            if (YGMarginLeadingValue(child, crossAxis)->unit == YGUnitAuto &&
-                child->style.margin[trailing[crossAxis]].unit == YGUnitAuto) {
+                YGMarginTrailingValue(child, crossAxis)->unit == YGUnitAuto) {
               leadingCrossDim += remainingCrossDim / 2;
-            } else if (child->style.margin[trailing[crossAxis]].unit == YGUnitAuto) {
+            } else if (YGMarginTrailingValue(child, crossAxis)->unit == YGUnitAuto) {
               // No-Op
-            } else if (child->style.margin[leading[crossAxis]].unit == YGUnitAuto) {
+            } else if (YGMarginLeadingValue(child, crossAxis)->unit == YGUnitAuto) {
               leadingCrossDim += remainingCrossDim;
             } else if (alignItem == YGAlignFlexStart) {
               // No-Op