mac: Implement custom AppKit Enter Fullscreen transition.

chrome/browser/ui/cocoa/browser_window_enter_fullscreen_transition.mm

+// Copyright 2015 The Chromium 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 "chrome/browser/ui/cocoa/browser_window_enter_fullscreen_transition.h"
+
+#include <QuartzCore/QuartzCore.h>
+
+#include "base/mac/scoped_cftyperef.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/mac/sdk_forward_declarations.h"
+
+namespace {
+
+NSString* const kPrimaryWindowAnimationID = @"PrimaryWindowAnimationID";
+NSString* const kSnapshotWindowAnimationID = @"SnapshotWindowAnimationID";
+NSString* const kAnimationIDKey = @"AnimationIDKey";
+
+// This class has two simultaneous animations to resize and reposition layers.
+// These animations must use the same timing function, otherwise there will be
+// visual discordance.
+NSString* const kTransformAnimationTimingFunction =
+    kCAMediaTimingFunctionEaseInEaseOut;
+
+}  // namespace
+
+@interface BrowserWindowEnterFullscreenTransition () {
+  // The window which is undergoing the fullscreen transition.
+  base::scoped_nsobject<NSWindow> primaryWindow_;
+
+  // A layer that holds a snapshot of the original state of |primaryWindow_|.
+  base::scoped_nsobject<CALayer> snapshotLayer_;
+
+  // A temporary window that holds |snapshotLayer_|.
+  base::scoped_nsobject<NSWindow> snapshotWindow_;
+
+  // The animation applied to |snapshotLayer_|.
+  base::scoped_nsobject<CAAnimationGroup> snapshotAnimation_;
+
+  // The animation applied to the root layer of |primaryWindow_|.
+  base::scoped_nsobject<CAAnimationGroup> primaryWindowAnimation_;
+
+  // The frame of the |primaryWindow_| before the transition began.
+  NSRect primaryWindowInitialFrame_;
+
+  // The background color of |primaryWindow_| before the transition began.
+  base::scoped_nsobject<NSColor> primaryWindowInitialBackgroundColor_;
+
+  // Whether |primaryWindow_| was opaque before the transition began.
+  BOOL primaryWindowInitialOpaque_;
+
+  // Whether the instance is in the process of changing the size of
+  // |primaryWindow_|.
+  BOOL changingPrimaryWindowSize_;
+
+  // The frame that |primaryWindow_| is expected to have after the transition
+  // is finished.
+  NSRect primaryWindowFinalFrame_;
+}
+
+// Takes a snapshot of |primaryWindow_| and puts it in |snapshotLayer_|.
+- (void)takeSnapshot;
+
+// Creates |snapshotWindow_| and adds |snapshotLayer_| to it.
+- (void)makeAndPrepareSnapshotWindow;
+
+// This method has several effects on |primaryWindow_|:
+//  - Saves current state.
+//  - Makes window transparent, with clear background.
+//  - Adds NSFullScreenWindowMask style mask.
+//  - Sets the size to the screen's size.
+- (void)preparePrimaryWindowForAnimation;
+
+// Applies the fullscreen animation to |snapshotLayer_|.
+- (void)animateSnapshotWindowWithDuration:(CGFloat)duration;
+
+// Applies the fullscreen animation to the root layer of |primaryWindow_|.
+- (void)animatePrimaryWindowWithDuration:(CGFloat)duration;
+
+// Override of CAAnimation delegate method.
+- (void)animationDidStop:(CAAnimation*)theAnimation finished:(BOOL)flag;
+
+// Returns the layer of the root view of |window|.
+- (CALayer*)rootLayerOfWindow:(NSWindow*)window;
+
+@end
+
+@implementation BrowserWindowEnterFullscreenTransition
+
+// -------------------------Public Methods----------------------------
+
+- (instancetype)initWithWindow:(NSWindow*)window {
+  DCHECK(window);
+  DCHECK([self rootLayerOfWindow:window]);
+  if ((self = [super init])) {
+    primaryWindow_.reset([window retain]);
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [snapshotAnimation_ setDelegate:nil];
+  [primaryWindowAnimation_ setDelegate:nil];
+  [super dealloc];
+}
+
+- (NSArray*)customWindowsToEnterFullScreen {
+  [self takeSnapshot];
+  [self makeAndPrepareSnapshotWindow];
+  [self preparePrimaryWindowForAnimation];
+  return @[ primaryWindow_.get(), snapshotWindow_.get() ];
+}
+
+- (void)startCustomAnimationToEnterFullScreenWithDuration:
+    (NSTimeInterval)duration {
+  [self animateSnapshotWindowWithDuration:duration];
+  [self animatePrimaryWindowWithDuration:duration];
+}
+
+- (BOOL)shouldWindowBeUnconstrained {
+  return changingPrimaryWindowSize_;
+}
+
+// -------------------------Private Methods----------------------------
+
+- (void)takeSnapshot {
+  base::ScopedCFTypeRef<CGImageRef> windowSnapshot(CGWindowListCreateImage(
+      CGRectNull, kCGWindowListOptionIncludingWindow,
+      [primaryWindow_ windowNumber], kCGWindowImageBoundsIgnoreFraming));
+  snapshotLayer_.reset([[CALayer alloc] init]);
+  [snapshotLayer_ setFrame:NSRectToCGRect([primaryWindow_ frame])];
+  [snapshotLayer_ setContents:static_cast<id>(windowSnapshot.get())];
+  [snapshotLayer_ setAnchorPoint:CGPointMake(0, 0)];
+  [snapshotLayer_ setBackgroundColor:CGColorCreateGenericRGB(0, 0, 0, 0)];
+}
+
+- (void)makeAndPrepareSnapshotWindow {
+  DCHECK(snapshotLayer_);
+
+  snapshotWindow_.reset(
+      [[NSWindow alloc] initWithContentRect:[[primaryWindow_ screen] frame]
+                                  styleMask:0
+                                    backing:NSBackingStoreBuffered
+                                      defer:NO]);
+  [[snapshotWindow_ contentView] setWantsLayer:YES];
+  [snapshotWindow_ setOpaque:NO];
+  [snapshotWindow_ setBackgroundColor:[NSColor clearColor]];
+  [snapshotWindow_ setAnimationBehavior:NSWindowAnimationBehaviorNone];
+
+  [snapshotWindow_ orderFront:nil];
+  [[[snapshotWindow_ contentView] layer] addSublayer:snapshotLayer_];
+
+  // Compute the frame of the snapshot layer such that the snapshot is
+  // positioned exactly on top of the original position of |primaryWindow_|.
+  NSRect snapshotLayerFrame =
+      [snapshotWindow_ convertRectFromScreen:[primaryWindow_ frame]];
+  [snapshotLayer_ setFrame:snapshotLayerFrame];
+}
+
+- (void)preparePrimaryWindowForAnimation {
+  // Save initial state of |primaryWindow_|.
+  primaryWindowInitialFrame_ = [primaryWindow_ frame];
+  primaryWindowInitialBackgroundColor_.reset(
+      [[primaryWindow_ backgroundColor] copy]);
+  primaryWindowInitialOpaque_ = [primaryWindow_ isOpaque];
+
+  primaryWindowFinalFrame_ = [[primaryWindow_ screen] frame];
+
+  // Make |primaryWindow_| invisible. This must happen before the window is
+  // resized, since resizing the window will call drawRect: and cause content
+  // to flash over the entire screen.
+  [primaryWindow_ setOpaque:NO];
+  [primaryWindow_ setBackgroundColor:[NSColor clearColor]];
+  CALayer* rootLayer = [self rootLayerOfWindow:primaryWindow_];
+  rootLayer.opacity = 0;
+
+  // As soon as the style mask includes the flag NSFullScreenWindowMask, the
+  // window is expected to receive fullscreen layout. This must be set before
+  // the window is resized, as that causes a relayout.
+  [primaryWindow_
+      setStyleMask:[primaryWindow_ styleMask] | NSFullScreenWindowMask];
+
+  // Resize |primaryWindow_|.
+  changingPrimaryWindowSize_ = YES;
+  [primaryWindow_ setFrame:primaryWindowFinalFrame_ display:YES];
+  changingPrimaryWindowSize_ = NO;
+}
+
+- (void)animateSnapshotWindowWithDuration:(CGFloat)duration {
+  // Move the snapshot layer until it's bottom-left corner is at the
+  // bottom-left corner of the screen.
+  CABasicAnimation* positionAnimation =
+      [CABasicAnimation animationWithKeyPath:@"position"];
+  positionAnimation.toValue = [NSValue valueWithPoint:NSZeroPoint];
+  positionAnimation.timingFunction = [CAMediaTimingFunction
+      functionWithName:kTransformAnimationTimingFunction];
+
+  // Expand the bounds until it covers the screen.
+  NSRect finalBounds = NSMakeRect(0, 0, NSWidth(primaryWindowFinalFrame_),
+                                  NSHeight(primaryWindowFinalFrame_));
+  CABasicAnimation* boundsAnimation =
+      [CABasicAnimation animationWithKeyPath:@"bounds"];
+  boundsAnimation.toValue = [NSValue valueWithRect:finalBounds];
+  boundsAnimation.timingFunction = [CAMediaTimingFunction
+      functionWithName:kTransformAnimationTimingFunction];
+
+  // Fade out the snapshot layer.
+  CABasicAnimation* opacityAnimation =
+      [CABasicAnimation animationWithKeyPath:@"opacity"];
+  opacityAnimation.toValue = @(0.0);
+  opacityAnimation.timingFunction =
+      [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
+
+  // Fill forwards, and don't remove the animation. When the animation
+  // completes, the entire window will be removed.
+  CAAnimationGroup* group = [CAAnimationGroup animation];
+  group.removedOnCompletion = NO;
+  group.fillMode = kCAFillModeForwards;
+  group.animations = @[ positionAnimation, boundsAnimation, opacityAnimation ];
+  group.duration = duration;
+  [group setValue:kSnapshotWindowAnimationID forKey:kAnimationIDKey];
+  group.delegate = self;
+
+  snapshotAnimation_.reset([group retain]);
+  [snapshotLayer_ addAnimation:group forKey:nil];
+}
+
+- (void)animatePrimaryWindowWithDuration:(CGFloat)duration {
+  // As soon as the window's root layer is scaled down, the opacity should be
+  // set back to 1. There are a couple of ways to do this. The easiest is to
+  // just have a dummy animation as part of the same animation group.
+  CABasicAnimation* opacityAnimation =
+      [CABasicAnimation animationWithKeyPath:@"opacity"];
+  opacityAnimation.fromValue = @(1.0);
+  opacityAnimation.toValue = @(1.0);
+
+  // The root layer's size should start scaled down to the initial size of
+  // |primaryWindow_|. The animation increases the size until the root layer
+  // fills the screen.
+  NSRect initialFrame = primaryWindowInitialFrame_;
+  NSRect endFrame = primaryWindowFinalFrame_;
+  CGFloat xScale = NSWidth(initialFrame) / NSWidth(endFrame);
+  CGFloat yScale = NSHeight(initialFrame) / NSHeight(endFrame);
+  CATransform3D initial = CATransform3DMakeScale(xScale, yScale, 1);
+  CABasicAnimation* transformAnimation =
+      [CABasicAnimation animationWithKeyPath:@"transform"];
+  transformAnimation.fromValue = [NSValue valueWithCATransform3D:initial];
+
+  CALayer* root = [self rootLayerOfWindow:primaryWindow_];
+
+  // Calculate the initial position of the root layer. This calculation is
+  // agnostic of the anchorPoint.
+  CGFloat layerStartPositionDeltaX = NSMidX(initialFrame) - NSMidX(endFrame);
+  CGFloat layerStartPositionDeltaY = NSMidY(initialFrame) - NSMidY(endFrame);
+  NSPoint layerStartPosition =
+      NSMakePoint(root.position.x + layerStartPositionDeltaX,
+                  root.position.y + layerStartPositionDeltaY);
+
+  // Animate the primary window from its initial position.
+  CABasicAnimation* positionAnimation =
+      [CABasicAnimation animationWithKeyPath:@"position"];
+  positionAnimation.fromValue = [NSValue valueWithPoint:layerStartPosition];
+
+  CAAnimationGroup* group = [CAAnimationGroup animation];
+  group.removedOnCompletion = NO;
+  group.fillMode = kCAFillModeForwards;
+  group.animations =
+      @[ transformAnimation, opacityAnimation, positionAnimation ];
+  group.timingFunction = [CAMediaTimingFunction
+      functionWithName:kTransformAnimationTimingFunction];
+  group.duration = duration;
+  [group setValue:kPrimaryWindowAnimationID forKey:kAnimationIDKey];
+  group.delegate = self;
+
+  primaryWindowAnimation_.reset([group retain]);
+
+  [root addAnimation:group forKey:kPrimaryWindowAnimationID];
+}
+
+- (void)animationDidStop:(CAAnimation*)theAnimation finished:(BOOL)flag {
+  NSString* animationID = [theAnimation valueForKey:kAnimationIDKey];
+  if ([animationID isEqual:kSnapshotWindowAnimationID]) {
+    [snapshotWindow_ orderOut:nil];
+    snapshotWindow_.reset();
+    snapshotLayer_.reset();
+    return;
+  }
+
+  if ([animationID isEqual:kPrimaryWindowAnimationID]) {
+    [primaryWindow_ setOpaque:YES];
+    [primaryWindow_ setBackgroundColor:primaryWindowInitialBackgroundColor_];
+    CALayer* root = [self rootLayerOfWindow:primaryWindow_];
+    root.opacity = 1;
+    [root removeAnimationForKey:kPrimaryWindowAnimationID];
+  }
+}
+
+- (CALayer*)rootLayerOfWindow:(NSWindow*)window {
+  return [[[window contentView] superview] layer];
+}
+
+@end