From bbd91446dd7a71e785b0405df68bc87fa1c9f3aa Mon Sep 17 00:00:00 2001
From: Samuel Susla <samuelsusla@fb.com>
Date: Mon, 30 Mar 2020 04:00:43 -0700
Subject: [PATCH] Include transform property when calling
 getRelativeLayoutMetrics

Summary:
Changelog: [Internal]

Current implementation of `measure` doesn't take transform into account..

So if you had a view which has width and height 100 and had `Scale(0.5, 0.5, 1)` (this will shrink view by half). Calling `getRelativeLayoutMetrics` would report its size being `{100, 100}`.
This applies if view's parent has transformation as well, because transformation is applied to all subviews of the view as well.

Reviewed By: mdvacca

Differential Revision: D20621590

fbshipit-source-id: 2cf902a0494291c821ecada56f810c5e6620db5a
---
 .../core/layout/LayoutableShadowNode.cpp      | 20 +++---
 .../core/tests/LayoutableShadowNodeTest.cpp   | 63 +++++++++++++++++++
 2 files changed, 75 insertions(+), 8 deletions(-)

diff --git a/ReactCommon/fabric/core/layout/LayoutableShadowNode.cpp b/ReactCommon/fabric/core/layout/LayoutableShadowNode.cpp
index 2108fd3826..4ae44ed720 100644
--- a/ReactCommon/fabric/core/layout/LayoutableShadowNode.cpp
+++ b/ReactCommon/fabric/core/layout/LayoutableShadowNode.cpp
@@ -55,15 +55,15 @@ static LayoutMetrics calculateOffsetForLayoutMetrics(
       return EmptyLayoutMetrics;
     }
 
-    auto origin = layoutableCurrentShadowNode->getLayoutMetrics().frame.origin;
+    auto frame = layoutableCurrentShadowNode->getLayoutMetrics().frame;
 
     if (policy.includeTransform) {
-      // The check for ScrollView will be implemented after we have
-      // a dedicated trait (part of `ShadowNodeTraits`) for that.
-      origin = origin * layoutableCurrentShadowNode->getTransform();
+      layoutMetrics.frame.size = layoutMetrics.frame.size *
+          layoutableCurrentShadowNode->getTransform();
+      frame = frame * layoutableCurrentShadowNode->getTransform();
     }
 
-    layoutMetrics.frame.origin += origin;
+    layoutMetrics.frame.origin += frame.origin;
   }
   return layoutMetrics;
 }
@@ -132,9 +132,13 @@ LayoutMetrics LayoutableShadowNode::getRelativeLayoutMetrics(
     return EmptyLayoutMetrics;
   }
 
-  auto layoutMetrics = dynamic_cast<LayoutableShadowNode const *>(newestChild)
-                           ->getLayoutMetrics();
-
+  auto layoutableNewestChild =
+      dynamic_cast<LayoutableShadowNode const *>(newestChild);
+  auto layoutMetrics = layoutableNewestChild->getLayoutMetrics();
+  if (policy.includeTransform) {
+    layoutMetrics.frame =
+        layoutMetrics.frame * layoutableNewestChild->getTransform();
+  }
   return calculateOffsetForLayoutMetrics(layoutMetrics, ancestors, policy);
 }
 
diff --git a/ReactCommon/fabric/core/tests/LayoutableShadowNodeTest.cpp b/ReactCommon/fabric/core/tests/LayoutableShadowNodeTest.cpp
index 02662038f9..9c13ae700f 100644
--- a/ReactCommon/fabric/core/tests/LayoutableShadowNodeTest.cpp
+++ b/ReactCommon/fabric/core/tests/LayoutableShadowNodeTest.cpp
@@ -71,14 +71,33 @@ class LayoutableShadowNodeTest : public ::testing::Test {
         familyAAA,
         traits);
 
+    auto familyAAAA = std::make_shared<ShadowNodeFamily>(
+        ShadowNodeFamilyFragment{
+            /* .tag = */ 11,
+            /* .surfaceId = */ 1,
+            /* .eventEmitter = */ nullptr,
+        },
+        eventDispatcher_,
+        componentDescriptor_);
+
+    nodeAAAA_ = std::make_shared<TestShadowNode>(
+        ShadowNodeFragment{
+            /* .props = */ std::make_shared<const TestProps>(),
+            /* .children = */ ShadowNode::emptySharedShadowNodeSharedList(),
+        },
+        familyAAAA,
+        traits);
+
     nodeA_->appendChild(nodeAA_);
     nodeAA_->appendChild(nodeAAA_);
+    nodeAAA_->appendChild(nodeAAAA_);
   }
 
   std::shared_ptr<EventDispatcher const> eventDispatcher_;
   std::shared_ptr<TestShadowNode> nodeA_;
   std::shared_ptr<TestShadowNode> nodeAA_;
   std::shared_ptr<TestShadowNode> nodeAAA_;
+  std::shared_ptr<TestShadowNode> nodeAAAA_;
   TestComponentDescriptor componentDescriptor_;
 };
 
@@ -98,6 +117,50 @@ TEST_F(LayoutableShadowNodeTest, relativeLayoutMetrics) {
   EXPECT_EQ(relativeLayoutMetrics.frame.origin.y, 20);
 }
 
+TEST_F(LayoutableShadowNodeTest, relativeLayoutMetricsOnTransformedNode) {
+  auto layoutMetrics = EmptyLayoutMetrics;
+  layoutMetrics.frame.size = {1000, 1000};
+  nodeA_->setLayoutMetrics(layoutMetrics);
+
+  layoutMetrics.frame.origin = {10, 20};
+  layoutMetrics.frame.size = {100, 200};
+  nodeAA_->_transform = Transform::Scale(0.5, 0.5, 1);
+  nodeAA_->setLayoutMetrics(layoutMetrics);
+
+  auto relativeLayoutMetrics = nodeAA_->getRelativeLayoutMetrics(*nodeA_, {});
+
+  EXPECT_EQ(relativeLayoutMetrics.frame.origin.x, 35);
+  EXPECT_EQ(relativeLayoutMetrics.frame.origin.y, 70);
+
+  EXPECT_EQ(relativeLayoutMetrics.frame.size.width, 50);
+  EXPECT_EQ(relativeLayoutMetrics.frame.size.height, 100);
+}
+
+TEST_F(LayoutableShadowNodeTest, relativeLayoutMetricsOnTransformedParent) {
+  auto layoutMetrics = EmptyLayoutMetrics;
+  layoutMetrics.frame.size = {1000, 1000};
+  nodeA_->setLayoutMetrics(layoutMetrics);
+  nodeAA_->setLayoutMetrics(layoutMetrics);
+
+  layoutMetrics.frame.origin = {10, 10};
+  layoutMetrics.frame.size = {100, 100};
+  nodeAAA_->_transform = Transform::Scale(0.5, 0.5, 1);
+  nodeAAA_->setLayoutMetrics(layoutMetrics);
+
+  layoutMetrics.frame.origin = {10, 10};
+  layoutMetrics.frame.size = {50, 50};
+  nodeAAAA_->setLayoutMetrics(layoutMetrics);
+
+  auto relativeLayoutMetrics =
+      nodeAAAA_->getRelativeLayoutMetrics(*nodeAA_, {});
+
+  EXPECT_EQ(relativeLayoutMetrics.frame.origin.x, 45);
+  EXPECT_EQ(relativeLayoutMetrics.frame.origin.y, 45);
+
+  EXPECT_EQ(relativeLayoutMetrics.frame.size.width, 25);
+  EXPECT_EQ(relativeLayoutMetrics.frame.size.height, 25);
+}
+
 TEST_F(LayoutableShadowNodeTest, relativeLayoutMetricsOnSameNode) {
   auto layoutMetrics = EmptyLayoutMetrics;
   layoutMetrics.frame.origin = {10, 20};