[iOS] Add platform view to integration_test example (#164144)

Adds a platform view that simply renders a blue square to the
integration_test
example, and updates the screenshot capture code to capture all windows,
ensuring that any native picture-in-picture, split views, etc. are
catpured.

Adds a screenshot test that captures the platform view alongside the
existing
test. Improved API for screenshot capture will land in a followup patch.

Fixes: https://github.com/flutter/flutter/issues/164129
Issue: https://github.com/flutter/flutter/issues/51890

## Pre-launch Checklist

- [X] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [X] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [X] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [X] I signed the [CLA].
- [X] I listed at least one issue that this PR fixes in the description
above.
- [X] I updated/added relevant documentation (doc comments with `///`).
- [X] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [X] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [X] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

packages/integration_test/example/.gitignore

@@ -46,4 +46,5 @@ app.*.map.json
 /android/app/release
 
 # Golden images.
-integration_test/integration_test_matches_golden_file.png
+integration_test/integration_test_widget_matches_golden_file.png
+integration_test/integration_test_screen_matches_golden_file.png

packages/integration_test/example/integration_test/matches_golden_test.dart

@@ -30,11 +30,22 @@ void main() {
 
     // TODO(matanlurey): Is this necessary?
     await tester.pumpAndSettle();
+    // TODO(cbracken): not only is it necessary, but so is this.
+    await tester.pumpAndSettle();
 
-    // Take a screenshot.
+    // Take a widget screenshot.
     await expectLater(
       find.byType(MaterialApp),
-      matchesGoldenFile('integration_test_matches_golden_file.png'),
+      matchesGoldenFile('integration_test_widget_matches_golden_file.png'),
+    );
+
+    // Take a full-screen screenshot.
+    final List<int> screenshot = await IntegrationTestWidgetsFlutterBinding.instance.takeScreenshot(
+      'integration_test_screen_matches_golden_file',
+    );
+    await expectLater(
+      screenshot,
+      matchesGoldenFile('integration_test_screen_matches_golden_file.png'),
     );
   });
 }

packages/integration_test/example/ios/Runner.xcodeproj/project.pbxproj

@@ -9,6 +9,7 @@
 /* Begin PBXBuildFile section */
 		1498D2341E8E89220040F4C2 /* GeneratedPluginRegistrant.m in Sources */ = {isa = PBXBuildFile; fileRef = 1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */; };
 		3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */ = {isa = PBXBuildFile; fileRef = 3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */; };
+		3BA56D9B2D36D966004F0F1C /* SimplePlatformView.m in Sources */ = {isa = PBXBuildFile; fileRef = 3BA56D9A2D36D960004F0F1C /* SimplePlatformView.m */; };
 		4DB404AC7CF2C89658A01173 /* libPods-RunnerTests.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 81BF64028CE7AE2E6196250D /* libPods-RunnerTests.a */; };
 		769541CB23A0351900E5C350 /* RunnerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 769541CA23A0351900E5C350 /* RunnerTests.m */; };
 		978B8F6F1D3862AE00F588F7 /* AppDelegate.m in Sources */ = {isa = PBXBuildFile; fileRef = 7AFFD8EE1D35381100E5BB4D /* AppDelegate.m */; };
@@ -48,6 +49,8 @@
 		1498D2321E8E86230040F4C2 /* GeneratedPluginRegistrant.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = GeneratedPluginRegistrant.h; sourceTree = "<group>"; };
 		1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = GeneratedPluginRegistrant.m; sourceTree = "<group>"; };
 		3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; name = AppFrameworkInfo.plist; path = Flutter/AppFrameworkInfo.plist; sourceTree = "<group>"; };
+		3BA56D992D36D939004F0F1C /* SimplePlatformView.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SimplePlatformView.h; sourceTree = "<group>"; };
+		3BA56D9A2D36D960004F0F1C /* SimplePlatformView.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SimplePlatformView.m; sourceTree = "<group>"; };
 		625A5A90428602E25C0DE2F6 /* libPods-Runner.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = "libPods-Runner.a"; sourceTree = BUILT_PRODUCTS_DIR; };
 		750225973AAB5D7832AFA60C /* Pods-RunnerTests.profile.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-RunnerTests.profile.xcconfig"; path = "Target Support Files/Pods-RunnerTests/Pods-RunnerTests.profile.xcconfig"; sourceTree = "<group>"; };
 		769541BF23A0337200E5C350 /* XCTest.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = XCTest.framework; path = Platforms/iPhoneOS.platform/Developer/Library/Frameworks/XCTest.framework; sourceTree = DEVELOPER_DIR; };
@@ -145,6 +148,8 @@
 		97C146F01CF9000F007C117D /* Runner */ = {
 			isa = PBXGroup;
 			children = (
+				3BA56D992D36D939004F0F1C /* SimplePlatformView.h */,
+				3BA56D9A2D36D960004F0F1C /* SimplePlatformView.m */,
 				7AFFD8ED1D35381100E5BB4D /* AppDelegate.h */,
 				7AFFD8EE1D35381100E5BB4D /* AppDelegate.m */,
 				97C146FA1CF9000F007C117D /* Main.storyboard */,
@@ -373,6 +378,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				978B8F6F1D3862AE00F588F7 /* AppDelegate.m in Sources */,
+				3BA56D9B2D36D966004F0F1C /* SimplePlatformView.m in Sources */,
 				97C146F31CF9000F007C117D /* main.m in Sources */,
 				1498D2341E8E89220040F4C2 /* GeneratedPluginRegistrant.m in Sources */,
 			);

packages/integration_test/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

@@ -72,6 +72,7 @@
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
+      enableGPUValidationMode = "1"
       allowLocationSimulation = "YES">
       <BuildableProductRunnable
          runnableDebuggingMode = "0">

packages/integration_test/example/ios/Runner/AppDelegate.m

@@ -4,12 +4,19 @@
 
 #include "AppDelegate.h"
 #include "GeneratedPluginRegistrant.h"
+#include "SimplePlatformView.h"
 
 @implementation AppDelegate
 
 - (BOOL)application:(UIApplication *)application
     didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   [GeneratedPluginRegistrant registerWithRegistry:self];
+
+  // Register platform view factory.
+  NSObject<FlutterPluginRegistrar>* registrar = [self registrarForPlugin:@"spv-plugin"];
+  SimplePlatformViewFactory* factory = [[SimplePlatformViewFactory alloc] initWithMessenger:registrar.messenger];
+  [registrar registerViewFactory:factory withId:@"simple-platform-view"];
+
   // Override point for customization after application launch.
   return [super application:application didFinishLaunchingWithOptions:launchOptions];
 }

packages/integration_test/example/ios/Runner/SimplePlatformView.h

@@ -0,0 +1,23 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Flutter/Flutter.h>
+#import <UIKit/UIKit.h>
+
+@interface SimplePlatformViewFactory : NSObject<FlutterPlatformViewFactory>
+
+- (instancetype _Nullable)initWithMessenger:(NSObject<FlutterBinaryMessenger>* _Nonnull)messenger;
+
+@end
+
+@interface SimplePlatformView : NSObject<FlutterPlatformView>
+
+- (instancetype _Nullable)initWithFrame:(CGRect)frame
+                         viewIdentifier:(int64_t)viewId
+                              arguments:(id _Nullable)args
+                        binaryMessenger:(NSObject<FlutterBinaryMessenger>* _Nonnull)messenger;
+
+- (UIView* _Nonnull)view;
+
+@end

packages/integration_test/example/ios/Runner/SimplePlatformView.m

@@ -0,0 +1,52 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "SimplePlatformView.h"
+
+@implementation SimplePlatformViewFactory {
+  NSObject<FlutterBinaryMessenger>* _messenger;
+}
+
+- (instancetype _Nullable)initWithMessenger:(NSObject<FlutterBinaryMessenger>* _Nonnull)messenger {
+  if (self = [super init]) {
+    _messenger = messenger;
+  }
+  return self;
+}
+
+- (nonnull NSObject<FlutterPlatformView>*)createWithFrame:(CGRect)frame
+                                           viewIdentifier:(int64_t)viewId
+                                                arguments:(id _Nullable)args {
+  return [[SimplePlatformView alloc] initWithFrame:frame
+                                    viewIdentifier:viewId
+                                         arguments:args
+                                   binaryMessenger:_messenger];
+}
+
+- (NSObject<FlutterMessageCodec>*)createArgsCodec {
+  return [FlutterStandardMessageCodec sharedInstance];
+}
+
+@end
+
+@implementation SimplePlatformView {
+  UIView* _view;
+}
+
+- (instancetype _Nullable)initWithFrame:(CGRect)frame
+                         viewIdentifier:(int64_t)viewId
+                              arguments:(id _Nullable)args
+                        binaryMessenger:(NSObject<FlutterBinaryMessenger>* _Nonnull)messenger {
+  if (self = [super init]) {
+    _view = [[UIView alloc] initWithFrame:frame];
+    _view.backgroundColor = UIColor.blueColor;
+  }
+  return self;
+}
+
+- (UIView* _Nonnull)view {
+  return _view;
+}
+
+@end

packages/integration_test/example/lib/my_app.dart

@@ -2,8 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:io' show Platform;
+import 'dart:io';
 import 'package:flutter/material.dart';
+import 'simple_platform_view.dart';
 
 // ignore_for_file: public_member_api_docs
 
@@ -22,7 +23,12 @@ class _MyAppState extends State<MyApp> {
     return MaterialApp(
       home: Scaffold(
         appBar: AppBar(title: const Text('Plugin example app')),
-        body: Center(child: Text('Platform: ${Platform.operatingSystem}\n')),
+        body: Column(
+          children: <Widget>[
+            Text('Platform: ${Platform.operatingSystem}\n'),
+            const Expanded(child: SimplePlatformView()),
+          ],
+        ),
       ),
     );
   }

packages/integration_test/example/lib/simple_platform_view.dart

@@ -0,0 +1,28 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
+/// A platform view that displays a blue fill.
+class SimplePlatformView extends StatelessWidget {
+  /// Creates a platform view that displays a blue fill.
+  const SimplePlatformView({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.android:
+        // TODO(cbracken): Implement. https://github.com/flutter/flutter/issues/164130
+        return Container();
+      case TargetPlatform.iOS:
+        return const UiKitView(viewType: 'simple-platform-view');
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.linux:
+      case TargetPlatform.macOS:
+      case TargetPlatform.windows:
+        throw UnimplementedError();
+    }
+  }
+}

packages/integration_test/ios/integration_test/Sources/integration_test/IntegrationTestPlugin.m

@@ -50,6 +50,11 @@ static NSString *const kMethodRevertImage = @"revertFlutterImage";
   [registrar addMethodCallDelegate:[self instance] channel:channel];
 }
 
+/// Handle method calls from Dart code:
+/// - allTestsFinished: Populate NSString* testResults property with a string summary of test run.
+/// - captureScreenshot: Capture a screenshot. Populate capturedScreenshotsByName["name"] with image.
+/// - convertSurfaceToImage: Android-only. Not implemented on iOS.
+/// - revertFlutterImage: Android-only. Not implemented on iOS.
 - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
   if ([call.method isEqualToString:kMethodTestFinished]) {
     self.testResults = call.arguments[@"results"];
@@ -73,18 +78,23 @@ static NSString *const kMethodRevertImage = @"revertFlutterImage";
 }
 
 - (UIImage *)capturePngScreenshot {
-  UIWindow *window = [UIApplication.sharedApplication.windows
+  // Get all windows in the app
-                      filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"keyWindow = YES"]].firstObject;
+  NSArray<UIWindow *> *windows = [UIApplication sharedApplication].windows;
-  CGRect screenshotBounds = window.bounds;
-  UIImage *image;
 
-  UIGraphicsImageRenderer *renderer = [[UIGraphicsImageRenderer alloc] initWithBounds:screenshotBounds];
+  // Find the overall bounding rect for all windows
+  CGRect screenBounds = [UIScreen mainScreen].bounds;
 
-  image = [renderer imageWithActions:^(UIGraphicsImageRendererContext *rendererContext) {
+  UIGraphicsImageRenderer *renderer = [[UIGraphicsImageRenderer alloc] initWithBounds:screenBounds];
-    [window drawViewHierarchyInRect:screenshotBounds afterScreenUpdates:YES];
+  UIImage *screenshot =
-  }];
+      [renderer imageWithActions:^(UIGraphicsImageRendererContext *_Nonnull rendererContext) {
+        for (UIWindow *window in windows) {
+          if (!window.hidden) {  // Render only visible windows
+            [window drawViewHierarchyInRect:window.frame afterScreenUpdates:YES];
+          }
+        }
+      }];
 
-  return image;
+  return screenshot;
 }
 
 @end