Merge "Fix fragment transition epicenter calculation" into androidx-master-dev

2 files changed, 130 insertions, 3 deletions

diff --git a/fragment/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java b/fragment/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java
index 4cb1f3462bd..4e4a7f75879 100644
--- a/fragment/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java
+++ b/fragment/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java
@@ -20,8 +20,10 @@ import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP_PREFIX;
 
 import android.annotation.SuppressLint;
 import android.graphics.Rect;
+import android.graphics.RectF;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.ViewParent;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.RestrictTo;
@@ -77,9 +79,32 @@ public abstract class FragmentTransitionImpl {
      * containing the bounds relative to the screen that the view is in.
      */
     protected void getBoundsOnScreen(View view, Rect epicenter) {
-        int[] loc = new int[2];
-        view.getLocationOnScreen(loc);
-        epicenter.set(loc[0], loc[1], loc[0] + view.getWidth(), loc[1] + view.getHeight());
+        if (!ViewCompat.isAttachedToWindow(view)) {
+            return;
+        }
+
+        final RectF rect = new RectF();
+        rect.set(0, 0, view.getWidth(), view.getHeight());
+
+        view.getMatrix().mapRect(rect);
+        rect.offset(view.getLeft(), view.getTop());
+
+        ViewParent parent = view.getParent();
+        while (parent instanceof View) {
+            View parentView = (View) parent;
+
+            rect.offset(-parentView.getScrollX(), -parentView.getScrollY());
+            parentView.getMatrix().mapRect(rect);
+            rect.offset(parentView.getLeft(), parentView.getTop());
+
+            parent = parentView.getParent();
+        }
+
+        final int[] loc = new int[2];
+        view.getRootView().getLocationOnScreen(loc);
+        rect.offset(loc[0], loc[1]);
+        epicenter.set(Math.round(rect.left), Math.round(rect.top), Math.round(rect.right),
+                Math.round(rect.bottom));
     }
 
     /**
diff --git a/transition/transition/src/androidTest/java/androidx/transition/EpicenterTest.kt b/transition/transition/src/androidTest/java/androidx/transition/EpicenterTest.kt
new file mode 100644
index 00000000000..9360122a8f3
--- /dev/null
+++ b/transition/transition/src/androidTest/java/androidx/transition/EpicenterTest.kt
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.transition
+
+import android.graphics.Rect
+import android.graphics.RectF
+import android.view.View
+import android.view.ViewGroup
+import android.widget.FrameLayout
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.filters.SmallTest
+import androidx.test.platform.app.InstrumentationRegistry
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@SmallTest
+@RunWith(AndroidJUnit4::class)
+class EpicenterTest : BaseTest() {
+
+    @Test
+    fun defaultEpicenter() {
+        testViewEpicenter {}
+    }
+
+    @Test
+    fun rotatedViewEpicenter() {
+        testViewEpicenter {
+            rotation = 180f
+        }
+    }
+
+    @Test
+    fun scaledPivotEpicenter() {
+        testViewEpicenter {
+            pivotX = width.toFloat()
+            pivotY = height.toFloat()
+            scaleX = 0.5f
+            scaleY = 0.5f
+        }
+    }
+
+    private fun testViewEpicenter(viewSetup: View.() -> Unit) {
+        val view = setupTestView()
+        view.viewSetup()
+        val transitionSupport = FragmentTransitionSupport()
+
+        val transition = AutoTransition()
+        transitionSupport.setEpicenter(transition, view)
+
+        val rect = RectF(0f, 0f, view.width.toFloat(), view.height.toFloat())
+        view.matrix.mapRect(rect)
+
+        rect.offset(view.left.toFloat(), view.top.toFloat())
+        val (parentX, parentY) = IntArray(2).apply {
+            (view.parent as View).getLocationOnScreen(this)
+        }
+        rect.offset(parentX.toFloat(), parentY.toFloat())
+
+        val expected = Rect().also {
+            rect.round(it)
+        }
+
+        assertThat(transition.epicenter).isEqualTo(expected)
+        InstrumentationRegistry.getInstrumentation().runOnMainSync {
+            (view.parent as ViewGroup).removeView(view)
+        }
+    }
+
+    /**
+     * Returns a view of size 100x100 located at (50, 50)
+     */
+    private fun setupTestView(): View {
+        val view = View(rule.activity)
+        InstrumentationRegistry.getInstrumentation().runOnMainSync {
+            rule.activity.root.addView(view, FrameLayout.LayoutParams(100, 100)
+                .apply {
+                    leftMargin = 50
+                    topMargin = 50
+                })
+            view.left = 50
+            view.top = 50
+            view.right = 150
+            view.bottom = 150
+        }
+        return view
+    }
+}
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