Rendering any UIViews into UIImage in one line

LICENSE

Copyright (c) 2013 Jamz Tang <jamz@jamztang.com>
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is furnished
to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

UIView-JTViewToImage.h

/*
 * This file is part of the http://ioscodesnippet.com
 * http://ioscodesnippet.com/2011/08/25/rendering-any-uiviews-into-uiimage-in-one-line/
 *
 * (c) Jamz Tang <jamz@jamztang.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

#import <UIKit/UIKit.h>

@interface UIView (JTViewToImage)

// - [UIImage toImage]
//
// Follow device screen scaling. If your view is sized 320 * 480, 
// it renders 320 * 480 on non-retina display devices, 
// and 640 * 960 on retina display devices
// Use this option for making high resolution view elements snapshots to display on retina devices
- (UIImage *)toImage;

// - [UIImage toImageWithScale]
//
// Force rendering in a given scale. Commonly used will be "1".
// Good for output or saving a static image with the exact size of the view element.
- (UIImage *)toImageWithScale:(CGFloat)scale;

// - [UIImage toImageWithScale:legacy:]
//
// Set legacy to YES to force use the old API instead of
// iOS 7's drawViewHierarchyInRect:afterScreenUpdates: API
- (UIImage *)toImageWithScale:(CGFloat)scale legacy:(BOOL)legacy;

@end

UIView-JTViewToImage.m

/*
 * This file is part of the http://ioscodesnippet.com
 * http://ioscodesnippet.com/2011/08/25/rendering-any-uiviews-into-uiimage-in-one-line/
 *
 * (c) Jamz Tang <jamz@jamztang.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

#import "UIView-JTViewToImage.h"
#import <QuartzCore/QuartzCore.h>

@implementation UIView (JTViewToImage)

static BOOL _supportDrawViewHierarchyInRect;

+ (void)load {
    if ([self instancesRespondToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)]) {
        _supportDrawViewHierarchyInRect = YES;
    } else {
        _supportDrawViewHierarchyInRect = NO;
    }
}

- (UIImage *)toImage {
    return [self toImageWithScale:0];
}

- (UIImage *)toImageWithScale:(CGFloat)scale {
    UIImage *copied = [self toImageWithScale:scale legacy:NO];
    return copied;
}

- (UIImage *)toImageWithScale:(CGFloat)scale legacy:(BOOL)legacy {
    // If scale is 0, it'll follows the screen scale for creating the bounds
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, scale);
    
    if (legacy || ! _supportDrawViewHierarchyInRect) {
        // - [CALayer renderInContext:] also renders subviews
        [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    } else {
        [self drawViewHierarchyInRect:self.bounds
                   afterScreenUpdates:YES];
    }
    
    // Get the image out of the context
    UIImage *copied = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    // Return the result
    return copied;
}

@end

UIView-JTViewToImage.podspec

Pod::Spec.new do |s|
  s.name         = "UIView-JTViewToImage"
  s.version      = "0.0.2"
  s.summary      = "Rendering any UIViews into UIImage in one line"
  s.homepage     = "https://gist.github.com/jamztang/1578446"
  s.author       = { "Jamz Tang" => "jamz@jamztang.com" }
  s.platform     = :ios
  s.source       = { :git => "git://gist.github.com/1578446.git", :tag => s.version.to_s }
  s.source_files  = '*.{h,m}'
  s.license      = { :type => 'MIT', :file => 'LICENSE' }
end