packages/flutter/lib/src/rendering/view.dart - external/github.com/flutter/flutter - Git at Google

 // 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 'dart:developer';
 import 'dart:io' show Platform;
 import 'dart:ui' as ui show Scene, SceneBuilder, FlutterView;

 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:vector_math/vector_math_64.dart';

 import 'binding.dart';
 import 'box.dart';
 import 'debug.dart';
 import 'layer.dart';
 import 'object.dart';

 /// The layout constraints for the root render object.
 @immutable
 class ViewConfiguration {
   /// Creates a view configuration.
   ///
   /// By default, the view has zero [size] and a [devicePixelRatio] of 1.0.
   const ViewConfiguration({
     this.size = Size.zero,
     this.devicePixelRatio = 1.0,
   });

   /// The size of the output surface.
   final Size size;

   /// The pixel density of the output surface.
   final double devicePixelRatio;

   /// Creates a transformation matrix that applies the [devicePixelRatio].
   Matrix4 toMatrix() {
     return Matrix4.diagonal3Values(devicePixelRatio, devicePixelRatio, 1.0);
   }

   @override
   bool operator ==(Object other) {
     if (other.runtimeType != runtimeType)
       return false;
     return other is ViewConfiguration
         && other.size == size
         && other.devicePixelRatio == devicePixelRatio;
   }

   @override
   int get hashCode => hashValues(size, devicePixelRatio);

   @override
   String toString() => '$size at ${debugFormatDouble(devicePixelRatio)}x';
 }

 /// The root of the render tree.
 ///
 /// The view represents the total output surface of the render tree and handles
 /// bootstrapping the rendering pipeline. The view has a unique child
 /// [RenderBox], which is required to fill the entire output surface.
 class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox> {
   /// Creates the root of the render tree.
   ///
   /// Typically created by the binding (e.g., [RendererBinding]).
   ///
   /// The [configuration] must not be null.
   RenderView({
     RenderBox? child,
     required ViewConfiguration configuration,
     required ui.FlutterView window,
   }) : assert(configuration != null),
        _configuration = configuration,
        _window = window {
     this.child = child;
   }

   /// The current layout size of the view.
   Size get size => _size;
   Size _size = Size.zero;

   /// The constraints used for the root layout.
   ViewConfiguration get configuration => _configuration;
   ViewConfiguration _configuration;
   /// The configuration is initially set by the `configuration` argument
   /// passed to the constructor.
   ///
   /// Always call [prepareInitialFrame] before changing the configuration.
   set configuration(ViewConfiguration value) {
     assert(value != null);
     if (configuration == value)
       return;
     _configuration = value;
     replaceRootLayer(_updateMatricesAndCreateNewRootLayer());
     assert(_rootTransform != null);
     markNeedsLayout();
   }

   final ui.FlutterView _window;

   /// Whether Flutter should automatically compute the desired system UI.
   ///
   /// When this setting is enabled, Flutter will hit-test the layer tree at the
   /// top and bottom of the screen on each frame looking for an
   /// [AnnotatedRegionLayer] with an instance of a [SystemUiOverlayStyle]. The
   /// hit-test result from the top of the screen provides the status bar settings
   /// and the hit-test result from the bottom of the screen provides the system
   /// nav bar settings.
   ///
   /// Setting this to false does not cause previous automatic adjustments to be
   /// reset, nor does setting it to true cause the app to update immediately.
   ///
   /// If you want to imperatively set the system ui style instead, it is
   /// recommended that [automaticSystemUiAdjustment] is set to false.
   ///
   /// See also:
   ///
   ///  * [AnnotatedRegion], for placing [SystemUiOverlayStyle] in the layer tree.
   ///  * [SystemChrome.setSystemUIOverlayStyle], for imperatively setting the system ui style.
   bool automaticSystemUiAdjustment = true;

   /// Bootstrap the rendering pipeline by preparing the first frame.
   ///
   /// This should only be called once, and must be called before changing
   /// [configuration]. It is typically called immediately after calling the
   /// constructor.
   ///
   /// This does not actually schedule the first frame. Call
   /// [PipelineOwner.requestVisualUpdate] on [owner] to do that.
   void prepareInitialFrame() {
     assert(owner != null);
     assert(_rootTransform == null);
     scheduleInitialLayout();
     scheduleInitialPaint(_updateMatricesAndCreateNewRootLayer());
     assert(_rootTransform != null);
   }

   Matrix4? _rootTransform;

   TransformLayer _updateMatricesAndCreateNewRootLayer() {
     _rootTransform = configuration.toMatrix();
     final TransformLayer rootLayer = TransformLayer(transform: _rootTransform);
     rootLayer.attach(this);
     assert(_rootTransform != null);
     return rootLayer;
   }

   // We never call layout() on this class, so this should never get
   // checked. (This class is laid out using scheduleInitialLayout().)
   @override
   void debugAssertDoesMeetConstraints() { assert(false); }

   @override
   void performResize() {
     assert(false);
   }

   @override
   void performLayout() {
     assert(_rootTransform != null);
     _size = configuration.size;
     assert(_size.isFinite);

     if (child != null)
       child!.layout(BoxConstraints.tight(_size));
   }

   @override
   void rotate({ int? oldAngle, int? newAngle, Duration? time }) {
     assert(false); // nobody tells the screen to rotate, the whole rotate() dance is started from our performResize()
   }

   /// Determines the set of render objects located at the given position.
   ///
   /// Returns true if the given point is contained in this render object or one
   /// of its descendants. Adds any render objects that contain the point to the
   /// given hit test result.
   ///
   /// The [position] argument is in the coordinate system of the render view,
   /// which is to say, in logical pixels. This is not necessarily the same
   /// coordinate system as that expected by the root [Layer], which will
   /// normally be in physical (device) pixels.
   bool hitTest(HitTestResult result, { required Offset position }) {
     if (child != null)
       child!.hitTest(BoxHitTestResult.wrap(result), position: position);
     result.add(HitTestEntry(this));
     return true;
   }

   /// Determines the set of mouse tracker annotations at the given position.
   ///
   /// See also:
   ///
   ///  * [Layer.findAllAnnotations], which is used by this method to find all
   ///    [AnnotatedRegionLayer]s annotated for mouse tracking.
   HitTestResult hitTestMouseTrackers(Offset position) {
     assert(position != null);
     final BoxHitTestResult result = BoxHitTestResult();
     hitTest(result, position: position);
     return result;
   }

   @override
   bool get isRepaintBoundary => true;

   @override
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
       context.paintChild(child!, offset);
   }

   @override
   void applyPaintTransform(RenderBox child, Matrix4 transform) {
     assert(_rootTransform != null);
     transform.multiply(_rootTransform!);
     super.applyPaintTransform(child, transform);
   }

   /// Uploads the composited layer tree to the engine.
   ///
   /// Actually causes the output of the rendering pipeline to appear on screen.
   void compositeFrame() {
     if (!kReleaseMode) {
       Timeline.startSync('COMPOSITING', arguments: timelineArgumentsIndicatingLandmarkEvent);
     }
     try {
       final ui.SceneBuilder builder = ui.SceneBuilder();
       final ui.Scene scene = layer!.buildScene(builder);
       if (automaticSystemUiAdjustment)
         _updateSystemChrome();
       _window.render(scene);
       scene.dispose();
       assert(() {
         if (debugRepaintRainbowEnabled || debugRepaintTextRainbowEnabled)
           debugCurrentRepaintColor = debugCurrentRepaintColor.withHue((debugCurrentRepaintColor.hue + 2.0) % 360.0);
         return true;
       }());
     } finally {
       if (!kReleaseMode) {
         Timeline.finishSync();
       }
     }
   }

   void _updateSystemChrome() {
     // Take overlay style from the place where a system status bar and system
     // navigation bar are placed to update system style overlay.
     // The center of the system navigation bar and the center of the status bar
     // are used to get SystemUiOverlayStyle's to update system overlay appearance.
     //
     //         Horizontal center of the screen
     //                 V
     //    ++++++++++++++++++++++++++
     //    |                        |
     //    |    System status bar   |  <- Vertical center of the status bar
     //    |                        |
     //    ++++++++++++++++++++++++++
     //    |                        |
     //    |        Content         |
     //    ~                        ~
     //    |                        |
     //    ++++++++++++++++++++++++++
     //    |                        |
     //    |  System navigation bar | <- Vertical center of the navigation bar
     //    |                        |
     //    ++++++++++++++++++++++++++ <- bounds.bottom
     final Rect bounds = paintBounds;
     // Center of the status bar
     final Offset top = Offset(
       // Horizontal center of the screen
       bounds.center.dx,
       // The vertical center of the system status bar. The system status bar
       // height is kept as top window padding.
       _window.padding.top / 2.0,
     );
     // Center of the navigation bar
     final Offset bottom = Offset(
       // Horizontal center of the screen
       bounds.center.dx,
       // Vertical center of the system navigation bar. The system navigation bar
       // height is kept as bottom window padding. The "1" needs to be subtracted
       // from the bottom because available pixels are in (0..bottom) range.
       // I.e. for a device with 1920 height, bound.bottom is 1920, but the most
       // bottom drawn pixel is at 1919 position.
       bounds.bottom - 1.0 - _window.padding.bottom / 2.0,
     );
     final SystemUiOverlayStyle? upperOverlayStyle = layer!.find<SystemUiOverlayStyle>(top);
     // Only android has a customizable system navigation bar.
     SystemUiOverlayStyle? lowerOverlayStyle;
     switch (defaultTargetPlatform) {
       case TargetPlatform.android:
         lowerOverlayStyle = layer!.find<SystemUiOverlayStyle>(bottom);
         break;
       case TargetPlatform.fuchsia:
       case TargetPlatform.iOS:
       case TargetPlatform.linux:
       case TargetPlatform.macOS:
       case TargetPlatform.windows:
         break;
     }
     // If there are no overlay styles in the UI don't bother updating.
     if (upperOverlayStyle != null || lowerOverlayStyle != null) {
       final SystemUiOverlayStyle overlayStyle = SystemUiOverlayStyle(
         statusBarBrightness: upperOverlayStyle?.statusBarBrightness,
         statusBarIconBrightness: upperOverlayStyle?.statusBarIconBrightness,
         statusBarColor: upperOverlayStyle?.statusBarColor,
         systemStatusBarContrastEnforced: upperOverlayStyle?.systemStatusBarContrastEnforced,
         systemNavigationBarColor: lowerOverlayStyle?.systemNavigationBarColor,
         systemNavigationBarDividerColor: lowerOverlayStyle?.systemNavigationBarDividerColor,
         systemNavigationBarIconBrightness: lowerOverlayStyle?.systemNavigationBarIconBrightness,
         systemNavigationBarContrastEnforced: lowerOverlayStyle?.systemNavigationBarContrastEnforced,
       );
       SystemChrome.setSystemUIOverlayStyle(overlayStyle);
     }
   }

   @override
   Rect get paintBounds => Offset.zero & (size * configuration.devicePixelRatio);

   @override
   Rect get semanticBounds {
     assert(_rootTransform != null);
     return MatrixUtils.transformRect(_rootTransform!, Offset.zero & size);
   }

   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     // call to ${super.debugFillProperties(description)} is omitted because the
     // root superclasses don't include any interesting information for this
     // class
     assert(() {
       properties.add(DiagnosticsNode.message('debug mode enabled - ${kIsWeb ? 'Web' :  Platform.operatingSystem}'));
       return true;
     }());
     properties.add(DiagnosticsProperty<Size>('window size', _window.physicalSize, tooltip: 'in physical pixels'));
     properties.add(DoubleProperty('device pixel ratio', _window.devicePixelRatio, tooltip: 'physical pixels per logical pixel'));
     properties.add(DiagnosticsProperty<ViewConfiguration>('configuration', configuration, tooltip: 'in logical pixels'));
     if (_window.platformDispatcher.semanticsEnabled)
       properties.add(DiagnosticsNode.message('semantics enabled'));
   }
 }
	// 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 'dart:developer';
	import 'dart:io' show Platform;
	import 'dart:ui' as ui show Scene, SceneBuilder, FlutterView;

	import 'package:flutter/foundation.dart';
	import 'package:flutter/services.dart';
	import 'package:vector_math/vector_math_64.dart';

	import 'binding.dart';
	import 'box.dart';
	import 'debug.dart';
	import 'layer.dart';
	import 'object.dart';

	/// The layout constraints for the root render object.
	@immutable
	class ViewConfiguration {
	/// Creates a view configuration.
	///
	/// By default, the view has zero [size] and a [devicePixelRatio] of 1.0.
	const ViewConfiguration({
	this.size = Size.zero,
	this.devicePixelRatio = 1.0,
	});

	/// The size of the output surface.
	final Size size;

	/// The pixel density of the output surface.
	final double devicePixelRatio;

	/// Creates a transformation matrix that applies the [devicePixelRatio].
	Matrix4 toMatrix() {
	return Matrix4.diagonal3Values(devicePixelRatio, devicePixelRatio, 1.0);
	}

	@override
	bool operator ==(Object other) {
	if (other.runtimeType != runtimeType)
	return false;
	return other is ViewConfiguration
	&& other.size == size
	&& other.devicePixelRatio == devicePixelRatio;
	}

	@override
	int get hashCode => hashValues(size, devicePixelRatio);

	@override
	String toString() => '$size at ${debugFormatDouble(devicePixelRatio)}x';
	}

	/// The root of the render tree.
	///
	/// The view represents the total output surface of the render tree and handles
	/// bootstrapping the rendering pipeline. The view has a unique child
	/// [RenderBox], which is required to fill the entire output surface.
	class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox> {
	/// Creates the root of the render tree.
	///
	/// Typically created by the binding (e.g., [RendererBinding]).
	///
	/// The [configuration] must not be null.
	RenderView({
	RenderBox? child,
	required ViewConfiguration configuration,
	required ui.FlutterView window,
	}) : assert(configuration != null),
	_configuration = configuration,
	_window = window {
	this.child = child;
	}

	/// The current layout size of the view.
	Size get size => _size;
	Size _size = Size.zero;

	/// The constraints used for the root layout.
	ViewConfiguration get configuration => _configuration;
	ViewConfiguration _configuration;
	/// The configuration is initially set by the `configuration` argument
	/// passed to the constructor.
	///
	/// Always call [prepareInitialFrame] before changing the configuration.
	set configuration(ViewConfiguration value) {
	assert(value != null);
	if (configuration == value)
	return;
	_configuration = value;
	replaceRootLayer(_updateMatricesAndCreateNewRootLayer());
	assert(_rootTransform != null);
	markNeedsLayout();
	}

	final ui.FlutterView _window;

	/// Whether Flutter should automatically compute the desired system UI.
	///
	/// When this setting is enabled, Flutter will hit-test the layer tree at the
	/// top and bottom of the screen on each frame looking for an
	/// [AnnotatedRegionLayer] with an instance of a [SystemUiOverlayStyle]. The
	/// hit-test result from the top of the screen provides the status bar settings
	/// and the hit-test result from the bottom of the screen provides the system
	/// nav bar settings.
	///
	/// Setting this to false does not cause previous automatic adjustments to be
	/// reset, nor does setting it to true cause the app to update immediately.
	///
	/// If you want to imperatively set the system ui style instead, it is
	/// recommended that [automaticSystemUiAdjustment] is set to false.
	///
	/// See also:
	///
	/// * [AnnotatedRegion], for placing [SystemUiOverlayStyle] in the layer tree.
	/// * [SystemChrome.setSystemUIOverlayStyle], for imperatively setting the system ui style.
	bool automaticSystemUiAdjustment = true;

	/// Bootstrap the rendering pipeline by preparing the first frame.
	///
	/// This should only be called once, and must be called before changing
	/// [configuration]. It is typically called immediately after calling the
	/// constructor.
	///
	/// This does not actually schedule the first frame. Call
	/// [PipelineOwner.requestVisualUpdate] on [owner] to do that.
	void prepareInitialFrame() {
	assert(owner != null);
	assert(_rootTransform == null);
	scheduleInitialLayout();
	scheduleInitialPaint(_updateMatricesAndCreateNewRootLayer());
	assert(_rootTransform != null);
	}

	Matrix4? _rootTransform;

	TransformLayer _updateMatricesAndCreateNewRootLayer() {
	_rootTransform = configuration.toMatrix();
	final TransformLayer rootLayer = TransformLayer(transform: _rootTransform);
	rootLayer.attach(this);
	assert(_rootTransform != null);
	return rootLayer;
	}

	// We never call layout() on this class, so this should never get
	// checked. (This class is laid out using scheduleInitialLayout().)
	@override
	void debugAssertDoesMeetConstraints() { assert(false); }

	@override
	void performResize() {
	assert(false);
	}

	@override
	void performLayout() {
	assert(_rootTransform != null);
	_size = configuration.size;
	assert(_size.isFinite);

	if (child != null)
	child!.layout(BoxConstraints.tight(_size));
	}

	@override
	void rotate({ int? oldAngle, int? newAngle, Duration? time }) {
	assert(false); // nobody tells the screen to rotate, the whole rotate() dance is started from our performResize()
	}

	/// Determines the set of render objects located at the given position.
	///
	/// Returns true if the given point is contained in this render object or one
	/// of its descendants. Adds any render objects that contain the point to the
	/// given hit test result.
	///
	/// The [position] argument is in the coordinate system of the render view,
	/// which is to say, in logical pixels. This is not necessarily the same
	/// coordinate system as that expected by the root [Layer], which will
	/// normally be in physical (device) pixels.
	bool hitTest(HitTestResult result, { required Offset position }) {
	if (child != null)
	child!.hitTest(BoxHitTestResult.wrap(result), position: position);
	result.add(HitTestEntry(this));
	return true;
	}

	/// Determines the set of mouse tracker annotations at the given position.
	///
	/// See also:
	///
	/// * [Layer.findAllAnnotations], which is used by this method to find all
	/// [AnnotatedRegionLayer]s annotated for mouse tracking.
	HitTestResult hitTestMouseTrackers(Offset position) {
	assert(position != null);
	final BoxHitTestResult result = BoxHitTestResult();
	hitTest(result, position: position);
	return result;
	}

	@override
	bool get isRepaintBoundary => true;

	@override
	void paint(PaintingContext context, Offset offset) {
	if (child != null)
	context.paintChild(child!, offset);
	}

	@override
	void applyPaintTransform(RenderBox child, Matrix4 transform) {
	assert(_rootTransform != null);
	transform.multiply(_rootTransform!);
	super.applyPaintTransform(child, transform);
	}

	/// Uploads the composited layer tree to the engine.
	///
	/// Actually causes the output of the rendering pipeline to appear on screen.
	void compositeFrame() {
	if (!kReleaseMode) {
	Timeline.startSync('COMPOSITING', arguments: timelineArgumentsIndicatingLandmarkEvent);
	}
	try {
	final ui.SceneBuilder builder = ui.SceneBuilder();
	final ui.Scene scene = layer!.buildScene(builder);
	if (automaticSystemUiAdjustment)
	_updateSystemChrome();
	_window.render(scene);
	scene.dispose();
	assert(() {
	if (debugRepaintRainbowEnabled \|\| debugRepaintTextRainbowEnabled)
	debugCurrentRepaintColor = debugCurrentRepaintColor.withHue((debugCurrentRepaintColor.hue + 2.0) % 360.0);
	return true;
	}());
	} finally {
	if (!kReleaseMode) {
	Timeline.finishSync();
	}
	}
	}

	void _updateSystemChrome() {
	// Take overlay style from the place where a system status bar and system
	// navigation bar are placed to update system style overlay.
	// The center of the system navigation bar and the center of the status bar
	// are used to get SystemUiOverlayStyle's to update system overlay appearance.
	//
	// Horizontal center of the screen
	// V
	// ++++++++++++++++++++++++++
	// \| \|
	// \| System status bar \| <- Vertical center of the status bar
	// \| \|
	// ++++++++++++++++++++++++++
	// \| \|
	// \| Content \|
	// ~ ~
	// \| \|
	// ++++++++++++++++++++++++++
	// \| \|
	// \| System navigation bar \| <- Vertical center of the navigation bar
	// \| \|
	// ++++++++++++++++++++++++++ <- bounds.bottom
	final Rect bounds = paintBounds;
	// Center of the status bar
	final Offset top = Offset(
	// Horizontal center of the screen
	bounds.center.dx,
	// The vertical center of the system status bar. The system status bar
	// height is kept as top window padding.
	_window.padding.top / 2.0,
	);
	// Center of the navigation bar
	final Offset bottom = Offset(
	// Horizontal center of the screen
	bounds.center.dx,
	// Vertical center of the system navigation bar. The system navigation bar
	// height is kept as bottom window padding. The "1" needs to be subtracted
	// from the bottom because available pixels are in (0..bottom) range.
	// I.e. for a device with 1920 height, bound.bottom is 1920, but the most
	// bottom drawn pixel is at 1919 position.
	bounds.bottom - 1.0 - _window.padding.bottom / 2.0,
	);
	final SystemUiOverlayStyle? upperOverlayStyle = layer!.find<SystemUiOverlayStyle>(top);
	// Only android has a customizable system navigation bar.
	SystemUiOverlayStyle? lowerOverlayStyle;
	switch (defaultTargetPlatform) {
	case TargetPlatform.android:
	lowerOverlayStyle = layer!.find<SystemUiOverlayStyle>(bottom);
	break;
	case TargetPlatform.fuchsia:
	case TargetPlatform.iOS:
	case TargetPlatform.linux:
	case TargetPlatform.macOS:
	case TargetPlatform.windows:
	break;
	}
	// If there are no overlay styles in the UI don't bother updating.
	if (upperOverlayStyle != null \|\| lowerOverlayStyle != null) {
	final SystemUiOverlayStyle overlayStyle = SystemUiOverlayStyle(
	statusBarBrightness: upperOverlayStyle?.statusBarBrightness,
	statusBarIconBrightness: upperOverlayStyle?.statusBarIconBrightness,
	statusBarColor: upperOverlayStyle?.statusBarColor,
	systemStatusBarContrastEnforced: upperOverlayStyle?.systemStatusBarContrastEnforced,
	systemNavigationBarColor: lowerOverlayStyle?.systemNavigationBarColor,
	systemNavigationBarDividerColor: lowerOverlayStyle?.systemNavigationBarDividerColor,
	systemNavigationBarIconBrightness: lowerOverlayStyle?.systemNavigationBarIconBrightness,
	systemNavigationBarContrastEnforced: lowerOverlayStyle?.systemNavigationBarContrastEnforced,
	);
	SystemChrome.setSystemUIOverlayStyle(overlayStyle);
	}
	}

	@override
	Rect get paintBounds => Offset.zero & (size * configuration.devicePixelRatio);

	@override
	Rect get semanticBounds {
	assert(_rootTransform != null);
	return MatrixUtils.transformRect(_rootTransform!, Offset.zero & size);
	}

	@override
	void debugFillProperties(DiagnosticPropertiesBuilder properties) {
	// call to ${super.debugFillProperties(description)} is omitted because the
	// root superclasses don't include any interesting information for this
	// class
	assert(() {
	properties.add(DiagnosticsNode.message('debug mode enabled - ${kIsWeb ? 'Web' : Platform.operatingSystem}'));
	return true;
	}());
	properties.add(DiagnosticsProperty<Size>('window size', _window.physicalSize, tooltip: 'in physical pixels'));
	properties.add(DoubleProperty('device pixel ratio', _window.devicePixelRatio, tooltip: 'physical pixels per logical pixel'));
	properties.add(DiagnosticsProperty<ViewConfiguration>('configuration', configuration, tooltip: 'in logical pixels'));
	if (_window.platformDispatcher.semanticsEnabled)
	properties.add(DiagnosticsNode.message('semantics enabled'));
	}
	}