From 071f576db99775e51d384e99373a86610f712a28 Mon Sep 17 00:00:00 2001
From: Emil Sjolander <emilsj@fb.com>
Date: Thu, 22 Dec 2016 02:57:15 -0800
Subject: [PATCH] BREAKING - Change aspect ratio to always be width/height

Summary:
@public

Aspect ratio being defined as width/height or height/width depending on the situation it was used in turned out to be very confusing. This diff makes aspect ratio always be defined as width/height irregardless of the usage.

Differential Revision: D4339132

fbshipit-source-id: e5da32750b55ddaf6acaf1cbd7662d86f2b480c3
---
 tests/YGAspectRatioTest.cpp | 4 ++--
 yoga/Yoga.c                 | 6 +++---
 yoga/Yoga.h                 | 3 +++
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/tests/YGAspectRatioTest.cpp b/tests/YGAspectRatioTest.cpp
index 22846c9b..8b28abdb 100644
--- a/tests/YGAspectRatioTest.cpp
+++ b/tests/YGAspectRatioTest.cpp
@@ -351,7 +351,7 @@ TEST(YogaTest, aspect_ratio_double_main) {
 
   const YGNodeRef root_child0 = YGNodeNew();
   YGNodeStyleSetWidth(root_child0, 50);
-  YGNodeStyleSetAspectRatio(root_child0, 2);
+  YGNodeStyleSetAspectRatio(root_child0, 0.5);
   YGNodeInsertChild(root, root_child0, 0);
 
   YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
@@ -372,7 +372,7 @@ TEST(YogaTest, aspect_ratio_half_main) {
 
   const YGNodeRef root_child0 = YGNodeNew();
   YGNodeStyleSetWidth(root_child0, 100);
-  YGNodeStyleSetAspectRatio(root_child0, 0.5);
+  YGNodeStyleSetAspectRatio(root_child0, 2);
   YGNodeInsertChild(root, root_child0, 0);
 
   YGNodeCalculateLayout(root, YGUndefined, YGUndefined, YGDirectionLTR);
diff --git a/yoga/Yoga.c b/yoga/Yoga.c
index 4762cee4..8b1c5fda 100644
--- a/yoga/Yoga.c
+++ b/yoga/Yoga.c
@@ -1062,7 +1062,7 @@ static void YGNodeComputeFlexBasisForChild(const YGNodeRef node,
     if (!YGValueIsUndefined(child->style.aspectRatio)) {
       if (!isMainAxisRow && childWidthMeasureMode == YGMeasureModeExactly) {
         child->layout.computedFlexBasis =
-            fmaxf(childWidth * child->style.aspectRatio,
+            fmaxf(childWidth / child->style.aspectRatio,
                   YGNodePaddingAndBorderForAxis(child, YGFlexDirectionColumn));
         return;
       } else if (isMainAxisRow && childHeightMeasureMode == YGMeasureModeExactly) {
@@ -1157,7 +1157,7 @@ static void YGNodeAbsoluteLayoutChild(const YGNodeRef node,
         childWidth = fmaxf(childHeight * child->style.aspectRatio,
                            YGNodePaddingAndBorderForAxis(child, YGFlexDirectionColumn));
       } else if (YGValueIsUndefined(childHeight)) {
-        childHeight = fmaxf(childWidth * child->style.aspectRatio,
+        childHeight = fmaxf(childWidth / child->style.aspectRatio,
                             YGNodePaddingAndBorderForAxis(child, YGFlexDirectionRow));
       }
     }
@@ -1880,7 +1880,7 @@ static void YGNodelayoutImpl(const YGNodeRef node,
         if (!YGValueIsUndefined(currentRelativeChild->style.aspectRatio)) {
           if (isMainAxisRow && childHeightMeasureMode != YGMeasureModeExactly) {
             childHeight =
-                fmaxf(childWidth * currentRelativeChild->style.aspectRatio,
+                fmaxf(childWidth / currentRelativeChild->style.aspectRatio,
                       YGNodePaddingAndBorderForAxis(currentRelativeChild, YGFlexDirectionColumn));
             childHeightMeasureMode = YGMeasureModeExactly;
           } else if (!isMainAxisRow && childWidthMeasureMode != YGMeasureModeExactly) {
diff --git a/yoga/Yoga.h b/yoga/Yoga.h
index 3bb96727..5e10b503 100644
--- a/yoga/Yoga.h
+++ b/yoga/Yoga.h
@@ -151,6 +151,9 @@ YG_NODE_STYLE_PROPERTY(float, MaxHeight, maxHeight);
 
 // Yoga specific properties, not compatible with flexbox specification
 // Aspect ratio control the size of the undefined dimension of a node.
+// Aspect ratio is encoded as a floating point value width/height. e.g. A value of 2 leads to a node
+// with a width twice the size of its height while a value of 0.5 gives the opposite effect.
+//
 // - On a node with a set width/height aspect ratio control the size of the unset dimension
 // - On a node with a set flex basis aspect ratio controls the size of the node in the cross axis if
 // unset