Implement the download arrow animation for Mac

chrome/browser/cocoa/download_started_animation_mac.mm

+// Copyright (c) 2009 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.
+//
+// This file contains the Mac implementation the download animation, displayed
+// at the start of a download. The animation produces an arrow pointing
+// downwards and animates towards the bottom of the window where the new
+// download appears in the download shelf.
+
+#include "chrome/browser/download/download_started_animation.h"
+
+#import <QuartzCore/QuartzCore.h>
+
+#include "app/resource_bundle.h"
+#include "base/scoped_cftyperef.h"
+#include "base/scoped_nsobject.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/browser/tab_contents/tab_contents_view_mac.h"
+#include "chrome/common/notification_registrar.h"
+#include "chrome/common/notification_service.h"
+#include "third_party/skia/include/utils/mac/SkCGUtils.h"
+
+class DownloadAnimationTabObserver;
+
+// A class for managing the Core Animation download animation.
+@interface DownloadStartedAnimationMac : NSObject {
+  // The download arrow image which we are responsible for freeing.
+  scoped_cftyperef<CGImageRef> image_;
+
+  // The TabContents we will animate in (weak).
+  TabContents* tabContents_;
+
+  // The cocoa view object for our TabContents (weak).
+  NSView* view_;
+
+  // The observer for the TabContents we are drawing on.
+  scoped_ptr<DownloadAnimationTabObserver> observer_;
+
+  // Our animation layer.
+  scoped_nsobject<CALayer> layer_;
+
+  // Set once the animation is complete, either by interrupting (via window
+  // close) or through normal a end of the animation.
+  BOOL isComplete_;
+};
+
+// Called by our DownloadAnimationTabObserver if the tab is hidden or closed.
+- (void)animationComplete;
+
+@end  // interface DownloadStartedAnimationMac.
+
+
+// A helper class to monitor tab hidden and closed notifications. If we receive
+// such a notification, we stop the animation.
+class DownloadAnimationTabObserver : public NotificationObserver {
+public:
+  DownloadAnimationTabObserver(DownloadStartedAnimationMac* owner,
+                               TabContents* tab_contents)
+      : owner_(owner),
+        tab_contents_(tab_contents) {
+    registrar_.Add(this,
+                   NotificationType::TAB_CONTENTS_HIDDEN,
+                   Source<TabContents>(tab_contents_));
+    registrar_.Add(this,
+                   NotificationType::TAB_CONTENTS_DESTROYED,
+                   Source<TabContents>(tab_contents_));
+  }
+
+  // Runs when a tab is hidden or destroyed. Let our owner know we should end
+  // the animation.
+  void Observe(NotificationType type,
+               const NotificationSource& source,
+               const NotificationDetails& details) {
+    registrar_.Remove(this,
+                      NotificationType::TAB_CONTENTS_HIDDEN,
+                      Source<TabContents>(tab_contents_));
+    registrar_.Remove(this,
+                      NotificationType::TAB_CONTENTS_DESTROYED,
+                      Source<TabContents>(tab_contents_));
+    [owner_ animationComplete];
+  }
+
+private:
+  // The object we need to inform when we get a notification. Weak.
+  DownloadStartedAnimationMac* owner_;
+
+  // The tab we are observing. Weak.
+  TabContents* tab_contents_;
+
+  // Used for registering to receive notifications and automatic clean up.
+  NotificationRegistrar registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadAnimationTabObserver);
+};
+
+
+@implementation DownloadStartedAnimationMac
+
+// Load the image of the download arrow.
+- (id)initWithTabContents:(TabContents*)tabContents {
+  if ((self = [super init])) {
+    SkBitmap* image_bitmap =
+        ResourceBundle::GetSharedInstance().GetBitmapNamed(
+            IDR_DOWNLOAD_ANIMATION_BEGIN);
+    image_.reset(SkCreateCGImageRef(*image_bitmap));
+    tabContents_ = tabContents;
+    view_ = tabContents_->GetContentNativeView();
+    observer_.reset(new DownloadAnimationTabObserver(self, tabContents));
+    isComplete_ = NO;
+  }
+  return self;
+}
+
+// Common clean up code.
+- (void)animationComplete {
+  if (isComplete_)
+    return;
+  isComplete_ = YES;
+  [view_ setWantsLayer:NO];
+  [layer_ removeAllAnimations];
+  [layer_ removeFromSuperlayer];
+}
+
+// Set up the animation and let Core Animation do all the hard work.
+- (void)animate {
+  // Figure out the positioning in the current tab. We try to position ourselves
+  // against the left edge, and three times the download image's height from the
+  // bottom of the tab, assuming there is enough room. If there isn't enough, we
+  // won't show the animation and let the shelf speak for itself.
+  gfx::Rect bounds;
+  tabContents_->GetContainerBounds(&bounds);
+  int imageWidth = CGImageGetWidth(image_);
+  int imageHeight = CGImageGetHeight(image_);
+  CGRect imageBounds = CGRectMake(0, 0, imageWidth, imageHeight);
+
+  // Sanity check the size in case there's no room to display the animation.
+  if (bounds.height() < imageHeight) {
+    [self release];
+    return;
+  }
+
+  int animationHeight = std::min(bounds.height(), 3 * imageHeight);
+  NSPoint start = NSMakePoint(0, animationHeight);
+  NSPoint stop = NSMakePoint(0, 0);  // Bottom of the tab.
+
+  // Set for the duration of the animation, or we won't see our layer. We reset
+  // this in the completion callback.
+  [view_ setWantsLayer:YES];
+
+  // CALayer initalization.
+  layer_.reset([[CALayer layer] retain]);
+  [layer_ setNeedsDisplay];
+  [layer_ setContents:(id)image_.get()];
+  [layer_ setAnchorPoint:CGPointMake(0, 0)];
+  [layer_ setFrame:imageBounds];
+  [[view_ layer] addSublayer:layer_];
+
+  // Positional animation.
+  CABasicAnimation *animation =
+      [CABasicAnimation animationWithKeyPath:@"position"];
+  [animation setFromValue:[NSValue valueWithPoint:start]];
+  [animation setToValue:[NSValue valueWithPoint:stop]];
+  [animation setDuration:0.6];
+  CAMediaTimingFunction* mediaFunction =
+      [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
+  [animation setTimingFunction:mediaFunction];
+  [animation setDelegate:self];
+  [layer_ addAnimation:animation forKey:@"downloadPosition"];
+
+  // Opacity animation.
+  animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
+  [animation setFromValue:[NSNumber numberWithFloat:1.0]];
+  [animation setToValue:[NSNumber numberWithFloat:0.0]];
+  [animation setDuration:1.5];  // Slightly longer, so it doesn't fade too much.
+  mediaFunction =
+      [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
+  [animation setTimingFunction:mediaFunction];
+  [layer_ addAnimation:animation forKey:@"downloadOpacity"];
+}
+
+// CAAnimation delegate method called when the animation is complete.
+- (void)animationDidStop:(CAAnimation *)animation finished:(BOOL)flag {
+  [self animationComplete];
+  [self release];
+}
+
+@end  // implementation DownloadStartedAnimationMac
+
+
+// static
+void DownloadStartedAnimation::Show(TabContents* tab_contents) {
+  DCHECK(tab_contents);
+
+  // Will be deleted when the animation is complete.
+  DownloadStartedAnimationMac* downloadArrow =
+      [[DownloadStartedAnimationMac alloc] initWithTabContents:tab_contents];
+
+  // Go!
+  [downloadArrow animate];
+}