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Create Snapshot Images from Webpages in Cocoa

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  1. //  MWWebSnapshot
  2. //
  3. //  Created by Jim McGowan on 08/09/2010.
  4. //  Copyright 2010 Jim McGowan. All rights reserved.
  5. //
  6. //  This code is made available under the BSD license.  
  7. //  Please see the accompanying license.txt file
  8. //  or view the license online at http://www.malkinware.com/developer/License.txt
  9. //
  10.  
  11. #import <Cocoa/Cocoa.h>
  12. #import <WebKit/WebKit.h>
  13.  
  14.  
  15. @interface MWWebSnapshot : NSObject 
  16. {
  17. 	void (^completionBlock)(NSImage *image);
  18. 	WebView *webView;
  19. }
  20.  
  21. + (void)takeSnapshotOfWebPageAtURL:(NSURL *)url completionBlock:(void (^)(NSImage *))block;
  22.  
  23. @end
  24.  
  25.  
  26.  
  27. @interface MWWebSnapshot()
  28. - (id)_initWithCompletionBlock:(void (^)(NSImage *))block;
  29. - (void)_beginDownloadFromURL:(NSURL *)url;
  30. @end
  31.  
  32.  
  33.  
  34. @implementation MWWebSnapshot
  35.  
  36.  
  37. + (void)takeSnapshotOfWebPageAtURL:(NSURL *)url completionBlock:(void (^)(NSImage *))block;
  38. {
  39. 	MWWebSnapshot *instance = [[self alloc] _initWithCompletionBlock:block];
  40. 	[instance _beginDownloadFromURL:url];
  41. 	[instance autorelease];
  42. }
  43.  
  44.  
  45. - (id)_initWithCompletionBlock:(void (^)(NSImage *))block;
  46. {
  47. 	self = [super init];
  48. 	if (self != nil)
  49. 	{
  50. 		completionBlock = [block copy];
  51.  
  52. 		webView = [[WebView alloc] initWithFrame:NSMakeRect(0.0, 0.0, 1000.0, 1000.0) 
  53.                                                frameName:nil 
  54.                                                groupName:nil];
  55. 		[webView setFrameLoadDelegate:self];
  56. 	}
  57. 	return self;
  58. }
  59.  
  60.  
  61. - (void)_beginDownloadFromURL:(NSURL *)url;
  62. {
  63. 	[self retain];
  64. 	[webView setMainFrameURL:[url absoluteString]];
  65. }
  66.  
  67.  
  68. - (void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame
  69. {
  70. 	if (frame != [webView mainFrame])
  71. 	{
  72. 		return;
  73. 	}
  74.  
  75. 	NSView *webFrameViewDocView = [[[webView mainFrame] frameView] documentView];
  76. 	NSRect cacheRect = [webFrameViewDocView bounds];
  77.  
  78. 	NSBitmapImageRep *bitmapRep = [webFrameViewDocView bitmapImageRepForCachingDisplayInRect:cacheRect];
  79. 	[webFrameViewDocView cacheDisplayInRect:cacheRect toBitmapImageRep:bitmapRep];
  80.  
  81. 	NSSize imgSize = cacheRect.size;
  82. 	if (imgSize.height > imgSize.width)
  83. 	{
  84. 		imgSize.height = imgSize.width;
  85. 	}
  86.  
  87. 	NSRect srcRect = NSZeroRect;
  88. 	srcRect.size = imgSize;
  89. 	srcRect.origin.y = cacheRect.size.height - imgSize.height;
  90.  
  91. 	NSRect destRect = NSZeroRect;
  92. 	destRect.size = imgSize;
  93.  
  94. 	NSImage *webImage = [[[NSImage alloc] initWithSize:imgSize] autorelease];
  95. 	[webImage lockFocus];
  96. 	[bitmapRep drawInRect:destRect 
  97.                      fromRect:srcRect 
  98.                     operation:NSCompositeCopy 
  99.                      fraction:1.0 
  100.                respectFlipped:YES 
  101.                         hints:nil];
  102. 	[webImage unlockFocus];
  103.  
  104. 	NSSize defaultDisplaySize;
  105. 	defaultDisplaySize.height = 64.0 * (imgSize.height / imgSize.width);
  106. 	defaultDisplaySize.width = 64.0;
  107. 	[webImage setSize:defaultDisplaySize];
  108.  
  109. 	completionBlock(webImage);
  110.  
  111. 	[self autorelease];
  112. }
  113.  
  114.  
  115. - (void)dealloc
  116. {
  117. 	[completionBlock release];
  118. 	[webView release];
  119.  
  120. 	[super dealloc];
  121. }
  122.  
  123. @end

URL: http://www.malkinware.com/developer/

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