[Mac] Adds a new view that will allow us to animate the height property of vi...

chrome/browser/cocoa/animatable_view.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.
+
+#import <Cocoa/Cocoa.h>
+#import <QuartzCore/QuartzCore.h>
+
+#import "chrome/browser/cocoa/animatable_view.h"
+
+// NSAnimation subclass that animates the height of an AnimatableView.  Allows
+// the caller to start and cancel the animation as desired.
+@interface NSHeightAnimation : NSAnimation {
+ @private
+  AnimatableView* view_;  // weak, owns us.
+  CGFloat startHeight_;
+  CGFloat endHeight_;
+}
+
+// Initialize a new height animation for the given view.  The animation will not
+// start until startAnimation: is called.
+- (id)initWithView:(AnimatableView*)view
+       finalHeight:(CGFloat)height
+          duration:(NSTimeInterval)duration;
+@end
+
+@implementation NSHeightAnimation
+- (id)initWithView:(AnimatableView*)view
+       finalHeight:(CGFloat)height
+          duration:(NSTimeInterval)duration {
+  if ((self = [super initWithDuration:duration
+                       animationCurve:NSAnimationEaseIn])) {
+    view_ = view;
+    startHeight_ = [view_ height];
+    endHeight_ = height;
+    [self setAnimationBlockingMode:NSAnimationNonblocking];
+    [self setDelegate:view_];
+  }
+  return self;
+}
+
+// Overridden to call setHeight for each progress tick.
+- (void)setCurrentProgress:(NSAnimationProgress)progress {
+  [super setCurrentProgress:progress];
+  [view_ setHeight:((progress * (endHeight_ - startHeight_)) + startHeight_)];
+}
+@end
+
+
+@implementation AnimatableView
+@synthesize delegate = delegate_;
+
+- (void)dealloc {
+  // Stop the animation if it is running, since it holds a pointer to this view.
+  [self stopAnimation];
+  [super dealloc];
+}
+
+- (CGFloat)height {
+  return [self frame].size.height;
+}
+
+- (void)setHeight:(CGFloat)newHeight {
+  // Force the height to be an integer because some animations look terrible
+  // with non-integer intermediate heights.  We only ever set integer heights
+  // for our views, so this shouldn't be a limitation in practice.
+  int height = floor(newHeight);
+  [resizeDelegate_ resizeView:self newHeight:height];
+}
+
+- (void)animateToNewHeight:(CGFloat)newHeight
+                  duration:(NSTimeInterval)duration {
+  [currentAnimation_ stopAnimation];
+
+  currentAnimation_.reset([[NSHeightAnimation alloc] initWithView:self
+                                                      finalHeight:newHeight
+                                                         duration:duration]);
+  [currentAnimation_ startAnimation];
+}
+
+- (void)stopAnimation {
+  [currentAnimation_ stopAnimation];
+}
+
+- (void)setResizeDelegate:(id<ViewResizer>)resizeDelegate {
+  resizeDelegate_ = resizeDelegate;
+}
+
+- (void)animationDidStop:(NSAnimation*)animation {
+  if ([delegate_ respondsToSelector:@selector(animationDidStop:)])
+    [delegate_ animationDidStop:animation];
+  currentAnimation_.reset(nil);
+}
+
+- (void)animationDidEnd:(NSAnimation*)animation {
+  if ([delegate_ respondsToSelector:@selector(animationDidEnd:)])
+    [delegate_ animationDidEnd:animation];
+  currentAnimation_.reset(nil);
+}
+
+@end