handle clamp

Author: Emmanuel Garcia

shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java

@@ -11,7 +11,6 @@
 import android.content.Context;
 import android.content.MutableContextWrapper;
 import android.os.Build;
-import android.util.DisplayMetrics;
 import android.util.SparseArray;
 import android.view.MotionEvent;
 import android.view.SurfaceView;
@@ -257,8 +256,6 @@ public long createForTextureLayer(
                   || Build.VERSION.SDK_INT < 23;
 
           if (!usesSoftwareRendering && shouldUseVirtualDisplay) {
-            validateVirtualDisplayDimensions(physicalWidth, physicalHeight);
-
             Log.i(TAG, "Hosting view in a virtual display for platform view: " + viewId);
             // API level 20 is required to use VirtualDisplay#setSurface.
             ensureValidAndroidVersion(20);
@@ -952,21 +949,6 @@ private static PointerCoords parsePointerCoords(Object rawCoords, float density)
     return coords;
   }
 
-  // Creating a VirtualDisplay larger than the size of the device screen size
-  // could cause the device to restart: https://github.com/flutter/flutter/issues/28978
-  private void validateVirtualDisplayDimensions(int width, int height) {
-    DisplayMetrics metrics = context.getResources().getDisplayMetrics();
-    if (height > metrics.heightPixels || width > metrics.widthPixels) {
-      String message =
-          String.format(
-              "Creating a virtual display of size: [%d, %d] "
-                  + "may result in problems (https://github.com/flutter/flutter/issues/2897). "
-                  + "It is larger than the device screen size: [%d, %d].",
-              width, height, metrics.widthPixels, metrics.heightPixels);
-      Log.w(TAG, message);
-    }
-  }
-
   private float getDisplayDensity() {
     return context.getResources().getDisplayMetrics().density;
   }

shell/platform/android/io/flutter/plugin/platform/VirtualDisplayController.java

@@ -10,16 +10,20 @@
 import android.content.Context;
 import android.hardware.display.DisplayManager;
 import android.hardware.display.VirtualDisplay;
+import android.util.DisplayMetrics;
 import android.view.MotionEvent;
 import android.view.Surface;
 import android.view.View;
 import android.view.ViewTreeObserver;
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
+import io.flutter.Log;
 import io.flutter.view.TextureRegistry;
+import java.util.Locale;
 
 @TargetApi(20)
 class VirtualDisplayController {
+  private static String TAG = "VirtualDisplayController";
 
   public static VirtualDisplayController create(
       Context context,
@@ -31,14 +35,53 @@ public static VirtualDisplayController create(
       int viewId,
       Object createParams,
       OnFocusChangeListener focusChangeListener) {
-    textureEntry.surfaceTexture().setDefaultBufferSize(width, height);
+
+    int selectedWidth = width;
+    int selectedHeight = height;
+
+    DisplayMetrics metrics = context.getResources().getDisplayMetrics();
+    if (selectedWidth == 0 || selectedHeight == 0) {
+      return null;
+    }
+    // Prevent https://github.com/flutter/flutter/issues/2897.
+    if (selectedWidth > metrics.widthPixels || selectedHeight > metrics.heightPixels) {
+      float aspectRatio = (float) selectedWidth / (float) selectedHeight;
+      int maybeWidth = (int) (metrics.heightPixels * aspectRatio);
+      int maybeHeight = (int) (metrics.widthPixels / aspectRatio);
+
+      if (maybeHeight <= metrics.heightPixels) {
+        selectedWidth = metrics.widthPixels;
+        selectedHeight = maybeHeight;
+      } else if (maybeWidth <= metrics.widthPixels) {
+        selectedHeight = metrics.heightPixels;
+        selectedWidth = maybeWidth;
+      } else {
+        return null;
+      }
+
+      String message =
+          String.format(
+              Locale.US,
+              "Resizing virtual display of size: [%d, %d] to size [%d, %d] "
+                  + "since it's larger than the device display size [%d, %d].",
+              width,
+              height,
+              selectedWidth,
+              selectedHeight,
+              metrics.widthPixels,
+              metrics.heightPixels);
+      Log.w(TAG, message);
+    }
+
+    textureEntry.surfaceTexture().setDefaultBufferSize(selectedWidth, selectedHeight);
     Surface surface = new Surface(textureEntry.surfaceTexture());
     DisplayManager displayManager =
         (DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE);
 
     int densityDpi = context.getResources().getDisplayMetrics().densityDpi;
     VirtualDisplay virtualDisplay =
-        displayManager.createVirtualDisplay("flutter-vd", width, height, densityDpi, surface, 0);
+        displayManager.createVirtualDisplay(
+            "flutter-vd", selectedWidth, selectedHeight, densityDpi, surface, 0);
 
     if (virtualDisplay == null) {
       return null;
@@ -54,8 +97,8 @@ public static VirtualDisplayController create(
             focusChangeListener,
             viewId,
             createParams);
-    controller.bufferWidth = width;
-    controller.bufferHeight = height;
+    controller.bufferWidth = selectedWidth;
+    controller.bufferHeight = selectedHeight;
     return controller;
   }
 

testing/scenario_app/android/app/src/androidTest/java/dev/flutter/scenariosui/PlatformViewWithSurfaceViewUiTest.java

@@ -123,4 +123,12 @@ public void testPlatformViewWithoutOverlayIntersection() throws Exception {
         activityRule.launchActivity(intent),
         goldName("testPlatformViewWithoutOverlayIntersection"));
   }
+
+  @Test
+  public void testPlatformViewLargerThanDisplaySize() throws Exception {
+    // Regression test for https://github.com/flutter/flutter/issues/2897.
+    intent.putExtra("scenario_name", "platform_view_larger_than_display_size");
+    ScreenshotUtil.capture(
+        activityRule.launchActivity(intent), goldName("testPlatformViewLargerThanDisplaySize"));
+  }
 }

testing/scenario_app/lib/src/platform_view.dart

@@ -114,6 +114,42 @@ class PlatformViewNoOverlayIntersectionScenario extends Scenario
   }
 }
 
+
+/// A platform view that is larger than the display size.
+/// This is only applicable on Android while using virtual displays.
+/// Related issue https://github.com/flutter/flutter/issues/2897.
+class PlatformViewLargerThanDisplaySize extends Scenario
+    with _BasePlatformViewScenarioMixin {
+  /// Creates the PlatformView scenario.
+  ///
+  /// The [dispatcher] parameter must not be null.
+  PlatformViewLargerThanDisplaySize(
+    PlatformDispatcher dispatcher, {
+    required this.id,
+  })  : assert(dispatcher != null),
+        super(dispatcher);
+
+  /// The platform view identifier.
+  final int id;
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+
+    addPlatformView(
+      id,
+      dispatcher: dispatcher,
+      sceneBuilder: builder,
+      width: 15000,
+      height: 60000,
+    );
+
+    finishBuilder(
+      builder,
+    );
+  }
+}
+
 /// A simple platform view with an overlay that partially intersects with the platform view.
 class PlatformViewPartialIntersectionScenario extends Scenario
     with _BasePlatformViewScenarioMixin {

testing/scenario_app/lib/src/scenarios.dart

@@ -24,6 +24,7 @@ Map<String, ScenarioFactory> _scenarios = <String, ScenarioFactory>{
   'locale_initialization': () => LocaleInitialization(PlatformDispatcher.instance),
   'platform_view': () => PlatformViewScenario(PlatformDispatcher.instance, id: _viewId++),
   'platform_view_no_overlay_intersection': () => PlatformViewNoOverlayIntersectionScenario(PlatformDispatcher.instance, id: _viewId++),
+  'platform_view_larger_than_display_size': () => PlatformViewLargerThanDisplaySize(PlatformDispatcher.instance, id: _viewId++),
   'platform_view_partial_intersection': () => PlatformViewPartialIntersectionScenario(PlatformDispatcher.instance, id: _viewId++),
   'platform_view_two_intersecting_overlays': () => PlatformViewTwoIntersectingOverlaysScenario(PlatformDispatcher.instance, id: _viewId++),
   'platform_view_one_overlay_two_intersecting_overlays': () => PlatformViewOneOverlayTwoIntersectingOverlaysScenario(PlatformDispatcher.instance, id: _viewId++),