FlutterView Class Reference

#include <FlutterView.h>

Inheritance diagram for FlutterView:

Instance Methods
(instancetype)	- NS_UNAVAILABLE
(instancetype)	- initWithFrame:
(instancetype)	- initWithCoder:
(instancetype)	- initWithDelegate:opaque:enableWideGamut:
(UIScreen *)	- screen
(MTLPixelFormat)	- pixelFormat
(nullable instancetype)	- initWithMTLDevice:commandQueue:delegate:threadSynchronizer:viewIdentifier:
(nullable instancetype)	- initWithFrame:pixelFormat:
(nonnull instancetype)	- initWithFrame:
(nullable instancetype)	- initWithCoder:
(nonnull instancetype)	- NS_UNAVAILABLE
(void)	- setBackgroundColor:
(void)	- didUpdateMouseCursor:
(instancetype)	- init [implementation]
(BOOL)	- isWideGamutSupported [implementation]
(void)	- layoutSubviews [implementation]
(void)	- drawLayer:inContext: [implementation]
(BOOL)	- isAccessibilityElement [implementation]
(instancetype)	- initWithMTLDevice:commandQueue:delegate:threadSynchronizer:viewIdentifier: [implementation]
(void)	- onPresent:withBlock: [implementation]
(void)	- reshaped [implementation]
(void)	- setBackgroundColor: [implementation]
(void)	- setFrameSize: [implementation]
(BOOL)	- isFlipped [implementation]
(BOOL)	- isOpaque [implementation]
(BOOL)	- acceptsFirstMouse: [implementation]
(BOOL)	- acceptsFirstResponder [implementation]
(void)	- didUpdateMouseCursor: [implementation]
(void)	- cursorUpdate: [implementation]
(void)	- viewDidChangeBackingProperties [implementation]
(BOOL)	- layer:shouldInheritContentsScale:fromWindow: [implementation]
(NSAccessibilityRole)	- accessibilityRole [implementation]
(NSString *)	- accessibilityLabel [implementation]
Instance Methods inherited from <FlutterSurfaceManagerDelegate>
(void)	- onPresent:withBlock:

Class Methods
(instancetype)	+ NS_UNAVAILABLE
(static void)	+ PrintWideGamutWarningOnce [implementation]
(void)	+ setForceSoftwareRendering: [implementation]
(Class)	+ layerClass [implementation]

Protected Attributes
FlutterViewIdentifier	_viewIdentifier
__weak id< FlutterViewDelegate >	_viewDelegate
FlutterThreadSynchronizer *	_threadSynchronizer
FlutterSurfaceManager *	_surfaceManager
NSCursor *	_lastCursor

Properties
BOOL	forceSoftwareRendering
FlutterSurfaceManager *	surfaceManager

Detailed Description

View capable of acting as a rendering target and input source for the Flutter engine.

Definition at line 34 of file FlutterView.h.

Method Documentation

acceptsFirstMouse:

- (BOOL) acceptsFirstMouse: (NSEvent*)  event

implementation

Declares that the initial mouse-down when the view is not in focus will send an event to the view.

Definition at line 17 of file FlutterView.mm.

                         :(NSEvent*)event {
  return YES;
}

acceptsFirstResponder

- (BOOL) acceptsFirstResponder

implementation

Definition at line 17 of file FlutterView.mm.

                              {
  // This is to ensure that FlutterView does not take first responder status from TextInputPlugin
  // on mouse clicks.
  return [_viewDelegate viewShouldAcceptFirstResponder:self];
}

accessibilityLabel

- (NSString *) accessibilityLabel

implementation

Definition at line 17 of file FlutterView.mm.

                                {
  // TODO(chunhtai): Provides a way to let developer customize the accessibility
  // label.
  // https://github.com/flutter/flutter/issues/75446
  NSString* applicationName =
      [NSBundle.mainBundle objectForInfoDictionaryKey:@"CFBundleDisplayName"];
  if (!applicationName) {
    applicationName = [NSBundle.mainBundle objectForInfoDictionaryKey:@"CFBundleName"];
  }
  return applicationName;
}

accessibilityRole

- (NSAccessibilityRole) accessibilityRole

implementation

Definition at line 17 of file FlutterView.mm.

                                         {
  return NSAccessibilityGroupRole;
}

cursorUpdate:

- (void) cursorUpdate: (NSEvent*)  event

implementation

Definition at line 17 of file FlutterView.mm.

                    :(NSEvent*)event {
  // Make sure to not override cursor when over a platform view.
  NSView* hitTestView = [self hitTest:[self convertPoint:event.locationInWindow fromView:nil]];
  if (hitTestView != self) {
    return;
  }
  [_lastCursor set];
  // It is possible that there is a platform view with NSTrackingArea below flutter content.
  // This could override the mouse cursor as a result of mouse move event. There is no good way
  // to prevent that short of swizzling [NSCursor set], so as a workaround force flutter cursor
  // in next runloop turn. This is not ideal, as it may cause the cursor flicker a bit.
  [[NSRunLoop currentRunLoop] performBlock:^{
    [_lastCursor set];
  }];
}

didUpdateMouseCursor: [1/2]

- (void) didUpdateMouseCursor:

(nonnull NSCursor *)

cursor

Called from the engine to notify the view that mouse cursor was updated while the mouse is over the view. The view is responsible from restoring the cursor when the mouse enters the view from another subview.

didUpdateMouseCursor: [2/2]

- (void) didUpdateMouseCursor: (NSCursor*)  cursor

implementation

Definition at line 17 of file FlutterView.mm.

                            :(NSCursor*)cursor {
  _lastCursor = cursor;
}

drawLayer:inContext:

- (void) drawLayer: (CALayer*)  layer inContext: (CGContextRef)  context

implementation

Definition at line 123 of file FlutterView.mm.

                 :(CALayer*)layer inContext:(CGContextRef)context {
  TRACE_EVENT0("flutter", "SnapshotFlutterView");
 
  if (layer != self.layer || context == nullptr) {
    return;
  }
 
  auto screenshot = [_delegate takeScreenshot:flutter::Rasterizer::ScreenshotType::UncompressedImage
                              asBase64Encoded:NO];
 
  if (!screenshot.data || screenshot.data->isEmpty() || screenshot.frame_size.isEmpty()) {
    return;
  }
 
  NSData* data = [NSData dataWithBytes:const_cast<void*>(screenshot.data->data())
                                length:screenshot.data->size()];
 
  fml::CFRef<CGDataProviderRef> image_data_provider(
      CGDataProviderCreateWithCFData(reinterpret_cast<CFDataRef>(data)));
 
  fml::CFRef<CGColorSpaceRef> colorspace(CGColorSpaceCreateDeviceRGB());
 
  // Defaults for RGBA8888.
  size_t bits_per_component = 8u;
  size_t bits_per_pixel = 32u;
  size_t bytes_per_row_multiplier = 4u;
  CGBitmapInfo bitmap_info =
      static_cast<CGBitmapInfo>(static_cast<uint32_t>(kCGImageAlphaPremultipliedLast) |
                                static_cast<uint32_t>(kCGBitmapByteOrder32Big));
 
  switch (screenshot.pixel_format) {
    case flutter::Rasterizer::ScreenshotFormat::kUnknown:
    case flutter::Rasterizer::ScreenshotFormat::kR8G8B8A8UNormInt:
      // Assume unknown is Skia and is RGBA8888. Keep defaults.
      break;
    case flutter::Rasterizer::ScreenshotFormat::kB8G8R8A8UNormInt:
      // Treat this as little endian with the alpha first so that it's read backwards.
      bitmap_info =
          static_cast<CGBitmapInfo>(static_cast<uint32_t>(kCGImageAlphaPremultipliedFirst) |
                                    static_cast<uint32_t>(kCGBitmapByteOrder32Little));
      break;
    case flutter::Rasterizer::ScreenshotFormat::kR16G16B16A16Float:
      bits_per_component = 16u;
      bits_per_pixel = 64u;
      bytes_per_row_multiplier = 8u;
      bitmap_info =
          static_cast<CGBitmapInfo>(static_cast<uint32_t>(kCGImageAlphaPremultipliedLast) |
                                    static_cast<uint32_t>(kCGBitmapFloatComponents) |
                                    static_cast<uint32_t>(kCGBitmapByteOrder16Little));
      break;
  }
 
  fml::CFRef<CGImageRef> image(CGImageCreate(
      screenshot.frame_size.width(),                             // size_t width
      screenshot.frame_size.height(),                            // size_t height
      bits_per_component,                                        // size_t bitsPerComponent
      bits_per_pixel,                                            // size_t bitsPerPixel,
      bytes_per_row_multiplier * screenshot.frame_size.width(),  // size_t bytesPerRow
      colorspace,                                                // CGColorSpaceRef space
      bitmap_info,                                               // CGBitmapInfo bitmapInfo
      image_data_provider,                                       // CGDataProviderRef provider
      nullptr,                                                   // const CGFloat* decode
      false,                                                     // bool shouldInterpolate
      kCGRenderingIntentDefault                                  // CGColorRenderingIntent intent
      ));
 
  const CGRect frame_rect =
      CGRectMake(0.0, 0.0, screenshot.frame_size.width(), screenshot.frame_size.height());
  CGContextSaveGState(context);
  // If the CGContext is not a bitmap based context, this returns zero.
  CGFloat height = CGBitmapContextGetHeight(context);
  if (height == 0) {
    height = CGFloat(screenshot.frame_size.height());
  }
  CGContextTranslateCTM(context, 0.0, height);
  CGContextScaleCTM(context, 1.0, -1.0);
  CGContextDrawImage(context, frame_rect, image);
  CGContextRestoreGState(context);
}

init

- (instancetype) init

implementation

Definition at line 11 of file FlutterView.mm.

                     {
  NSAssert(NO, @"FlutterView must initWithDelegate");
  return nil;
}

initWithCoder: [1/2]

- (nullable instancetype) initWithCoder:

(nonnull NSCoder *)

NS_UNAVAILABLE

initWithCoder: [2/2]

- (instancetype) initWithCoder:

(NSCoder*)

NS_UNAVAILABLE

Definition at line 11 of file FlutterView.mm.

                             :(NSCoder*)aDecoder {
  NSAssert(NO, @"FlutterView must initWithDelegate");
  return nil;
}

initWithDelegate:opaque:enableWideGamut:

- (instancetype) initWithDelegate:		(id<FlutterViewEngineDelegate>)	delegate
opaque:		(BOOL)	opaque
enableWideGamut:		(BOOL)	NS_DESIGNATED_INITIALIZER

Definition at line 11 of file FlutterView.mm.

                                :(id<FlutterViewEngineDelegate>)delegate
                          opaque:(BOOL)opaque
                 enableWideGamut:(BOOL)isWideGamutEnabled {
  if (delegate == nil) {
    NSLog(@"FlutterView delegate was nil.");
    [self release];
    return nil;
  }
 
  self = [super initWithFrame:CGRectNull];
 
  if (self) {
    _delegate = delegate;
    _isWideGamutEnabled = isWideGamutEnabled;
    self.layer.opaque = opaque;
 
    // This line is necessary. CoreAnimation(or UIKit) may take this to do
    // something to compute the final frame presented on screen, if we don't set this,
    // it will make it take long time for us to take next CAMetalDrawable and will
    // cause constant junk during rendering.
    self.backgroundColor = UIColor.clearColor;
  }
 
  return self;
}

initWithFrame: [1/2]

- (instancetype) initWithFrame:

(CGRect)

NS_UNAVAILABLE

Definition at line 11 of file FlutterView.mm.

                             :(CGRect)frame {
  NSAssert(NO, @"FlutterView must initWithDelegate");
  return nil;
}

initWithFrame: [2/2]

- (nonnull instancetype) initWithFrame:

(NSRect)

NS_UNAVAILABLE

initWithFrame:pixelFormat:

- (nullable instancetype) initWithFrame:		(NSRect)	frameRect
pixelFormat:		(nullable NSOpenGLPixelFormat *)	NS_UNAVAILABLE

initWithMTLDevice:commandQueue:delegate:threadSynchronizer:viewIdentifier: [1/2]

- (instancetype) initWithMTLDevice: (id<MTLDevice>)  device commandQueue: (id<MTLCommandQueue>)  commandQueue delegate: (id<FlutterViewDelegate>)  delegate threadSynchronizer: (FlutterThreadSynchronizer*)  threadSynchronizer viewIdentifier: (FlutterViewIdentifier)  viewIdentifier

implementation

Definition at line 17 of file FlutterView.mm.

                                 :(id<MTLDevice>)device
                     commandQueue:(id<MTLCommandQueue>)commandQueue
                         delegate:(id<FlutterViewDelegate>)delegate
               threadSynchronizer:(FlutterThreadSynchronizer*)threadSynchronizer
                   viewIdentifier:(FlutterViewIdentifier)viewIdentifier {
  self = [super initWithFrame:NSZeroRect];
  if (self) {
    [self setWantsLayer:YES];
    [self setBackgroundColor:[NSColor blackColor]];
    [self setLayerContentsRedrawPolicy:NSViewLayerContentsRedrawDuringViewResize];
    _viewIdentifier = viewIdentifier;
    _viewDelegate = delegate;
    _threadSynchronizer = threadSynchronizer;
    _surfaceManager = [[FlutterSurfaceManager alloc] initWithDevice:device
                                                       commandQueue:commandQueue
                                                              layer:self.layer
                                                           delegate:self];
  }
  return self;
}

initWithMTLDevice:commandQueue:delegate:threadSynchronizer:viewIdentifier: [2/2]

- (nullable instancetype) initWithMTLDevice:		(nonnull id< MTLDevice >)	device
commandQueue:		(nonnull id< MTLCommandQueue >)	commandQueue
delegate:		(nonnull id< FlutterViewDelegate >)	delegate
threadSynchronizer:		(nonnull FlutterThreadSynchronizer *)	threadSynchronizer
viewIdentifier:		(FlutterViewIdentifier)	NS_DESIGNATED_INITIALIZER

Initialize a FlutterView that will be rendered to using Metal rendering apis.

isAccessibilityElement

- (BOOL) isAccessibilityElement

implementation

Definition at line 123 of file FlutterView.mm.

                               {
  // iOS does not provide an API to query whether the voice control
  // is turned on or off. It is likely at least one of the assitive
  // technologies is turned on if this method is called. If we do
  // not catch it in notification center, we will catch it here.
  //
  // TODO(chunhtai): Remove this workaround once iOS provides an
  // API to query whether voice control is enabled.
  // https://github.com/flutter/flutter/issues/76808.
  [_delegate flutterViewAccessibilityDidCall];
  return NO;
}

isFlipped

- (BOOL) isFlipped

implementation

Declares that the view uses a flipped coordinate system, consistent with Flutter conventions.

Definition at line 17 of file FlutterView.mm.

                  {
  return YES;
}

isOpaque

- (BOOL) isOpaque

implementation

Definition at line 17 of file FlutterView.mm.

                 {
  return YES;
}

isWideGamutSupported

- (BOOL) isWideGamutSupported

implementation

Definition at line 11 of file FlutterView.mm.

                             {
  if (![_delegate isUsingImpeller]) {
    return NO;
  }
 
  FML_DCHECK(self.screen);
 
  // This predicates the decision on the capabilities of the iOS device's
  // display.  This means external displays will not support wide gamut if the
  // device's display doesn't support it.  It practice that should be never.
  return self.screen.traitCollection.displayGamut != UIDisplayGamutSRGB;
}

layer:shouldInheritContentsScale:fromWindow:

- (BOOL) layer: (CALayer*)  layer shouldInheritContentsScale: (CGFloat)  newScale fromWindow: (NSWindow*)  window

implementation

Definition at line 17 of file FlutterView.mm.

             :(CALayer*)layer
    shouldInheritContentsScale:(CGFloat)newScale
                    fromWindow:(NSWindow*)window {
  return YES;
}

layerClass

+ (Class) layerClass

implementation

Definition at line 123 of file FlutterView.mm.

                    {
  return flutter::GetCoreAnimationLayerClassForRenderingAPI(
      flutter::GetRenderingAPIForProcess(FlutterView.forceSoftwareRendering));
}

layoutSubviews

- (void) layoutSubviews

implementation

Definition at line 86 of file FlutterView.mm.

                       {
  if ([self.layer isKindOfClass:NSClassFromString(@"CAMetalLayer")]) {
// It is a known Apple bug that CAMetalLayer incorrectly reports its supported
// SDKs. It is, in fact, available since iOS 8.
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunguarded-availability-new"
    CAMetalLayer* layer = (CAMetalLayer*)self.layer;
#pragma clang diagnostic pop
    CGFloat screenScale = self.screen.scale;
    layer.allowsGroupOpacity = YES;
    layer.contentsScale = screenScale;
    layer.rasterizationScale = screenScale;
    layer.framebufferOnly = flutter::Settings::kSurfaceDataAccessible ? NO : YES;
    BOOL isWideGamutSupported = self.isWideGamutSupported;
    if (_isWideGamutEnabled && isWideGamutSupported) {
      CGColorSpaceRef srgb = CGColorSpaceCreateWithName(kCGColorSpaceExtendedSRGB);
      layer.colorspace = srgb;
      CFRelease(srgb);
      layer.pixelFormat = MTLPixelFormatBGRA10_XR;
    } else if (_isWideGamutEnabled && !isWideGamutSupported) {
      PrintWideGamutWarningOnce();
    }
  }
 
  [super layoutSubviews];
}

NS_UNAVAILABLE [1/3]

+ (instancetype) NS_UNAVAILABLE

NS_UNAVAILABLE [2/3]

- (instancetype) NS_UNAVAILABLE

NS_UNAVAILABLE [3/3]

- (nonnull instancetype) NS_UNAVAILABLE

onPresent:withBlock:

- (void) onPresent: (CGSize)  frameSize withBlock: (dispatch_block_t)  block

implementation

Definition at line 17 of file FlutterView.mm.

                 :(CGSize)frameSize withBlock:(dispatch_block_t)block {
  [_threadSynchronizer performCommitForView:_viewIdentifier size:frameSize notify:block];
}

pixelFormat

- (MTLPixelFormat) pixelFormat

Definition at line 11 of file FlutterView.mm.

                              {
  if ([self.layer isKindOfClass:NSClassFromString(@"CAMetalLayer")]) {
// It is a known Apple bug that CAMetalLayer incorrectly reports its supported
// SDKs. It is, in fact, available since iOS 8.
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunguarded-availability-new"
    CAMetalLayer* layer = (CAMetalLayer*)self.layer;
    return layer.pixelFormat;
  }
  return MTLPixelFormatBGRA8Unorm;
}

PrintWideGamutWarningOnce

+ (static void) PrintWideGamutWarningOnce

implementation

Definition at line 86 of file FlutterView.mm.

                                        {
  static BOOL did_print = NO;
  if (did_print) {
    return;
  }
  FML_DLOG(WARNING) << "Rendering wide gamut colors is turned on but isn't "
                       "supported, downgrading the color gamut to sRGB.";
  did_print = YES;
}

reshaped

- (void) reshaped

implementation

Reimplemented in TestFlutterView.

Definition at line 17 of file FlutterView.mm.

                 {
  CGSize scaledSize = [self convertSizeToBacking:self.bounds.size];
  [_threadSynchronizer beginResizeForView:_viewIdentifier
                                     size:scaledSize
                                   notify:^{
                                     [_viewDelegate viewDidReshape:self];
                                   }];
}

screen

- (UIScreen *) screen

Definition at line 11 of file FlutterView.mm.

                    {
  if (@available(iOS 13.0, *)) {
    return self.window.windowScene.screen;
  }
  return UIScreen.mainScreen;
}

setBackgroundColor: [1/2]

- (void) setBackgroundColor:

(nonnull NSColor *)

color

By default, the FlutterSurfaceManager creates two layers to manage Flutter content, the content layer and containing layer. To set the native background color, onto which the Flutter content is drawn, call this method with the NSColor which you would like to override the default, black background color with.

setBackgroundColor: [2/2]

- (void) setBackgroundColor: (NSColor*)  color

implementation

Definition at line 17 of file FlutterView.mm.

                          :(NSColor*)color {
  self.layer.backgroundColor = color.CGColor;
}

setForceSoftwareRendering:

+ (void) setForceSoftwareRendering: (BOOL)  forceSoftwareRendering

implementation

Definition at line 123 of file FlutterView.mm.

                                 :(BOOL)forceSoftwareRendering {
  _forceSoftwareRendering = forceSoftwareRendering;
}

setFrameSize:

- (void) setFrameSize: (NSSize)  newSize

implementation

Definition at line 17 of file FlutterView.mm.

                    :(NSSize)newSize {
  [super setFrameSize:newSize];
  [self reshaped];
}

viewDidChangeBackingProperties

- (void) viewDidChangeBackingProperties

implementation

Definition at line 17 of file FlutterView.mm.

                                       {
  [super viewDidChangeBackingProperties];
  // Force redraw
  [_viewDelegate viewDidReshape:self];
}

Member Data Documentation

_lastCursor

- (NSCursor*) _lastCursor

protected

Provided by category FlutterView().

Definition at line 17 of file FlutterView.mm.

_surfaceManager

- (FlutterSurfaceManager*) _surfaceManager

protected

Provided by category FlutterView().

Definition at line 16 of file FlutterView.mm.

_threadSynchronizer

- (FlutterThreadSynchronizer*) _threadSynchronizer

protected

Provided by category FlutterView().

Definition at line 15 of file FlutterView.mm.

_viewDelegate

- (__weak id<FlutterViewDelegate>) _viewDelegate

protected

Provided by category FlutterView().

Definition at line 14 of file FlutterView.mm.

_viewIdentifier

- (FlutterViewIdentifier) _viewIdentifier

protected

Provided by category FlutterView().

Definition at line 13 of file FlutterView.mm.

Property Documentation

forceSoftwareRendering

- (BOOL) forceSoftwareRendering

readwritenonatomicassign

Definition at line 49 of file FlutterView.h.

surfaceManager

- (FlutterSurfaceManager *) surfaceManager

readnonatomicassign

Returns SurfaceManager for this view. SurfaceManager is responsible for providing and presenting render surfaces.

Definition at line 57 of file FlutterView.h.

---

The documentation for this class was generated from the following files:

• shell/platform/darwin/ios/framework/Source/FlutterView.h
• shell/platform/darwin/macos/framework/Source/FlutterView.h
• shell/platform/darwin/ios/framework/Source/FlutterView.mm
• shell/platform/darwin/macos/framework/Source/FlutterView.mm