我已经多次测试过在Cocos2D上截取屏幕截图。唯一适合我的方法是将此类别添加到项目中：
标题
/*
* CCNode+Screenshot for cocos2d: https://github.com/pedrohub/
*
* Created by Martin Walsh on 23/08/2012.
* Copyright (c) 2012 Pedro LTD http://www.visitpedro.com All rights reserved.
*
* 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.
*
*/
#import "CCNode.h"
typedef void (^ScreenshotCompletionBlock) (UIImage *image);
@interface CCNode (Screenshot)
@property(nonatomic, copy) ScreenshotCompletionBlock completionBlock;
-(void) getScreenshot:(ScreenshotCompletionBlock) block;
-(void) screenshot:(ccTime) dt;
@end
实施
/*
* CCNode+Screenshot for cocos2d: https://github.com/pedrohub/
*
* Created by Martin Walsh on 23/08/2012.
* Copyright (c) 2012 Pedro LTD http://www.visitpedro.com All rights reserved.
*
* 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.
*
* Description : Take a screenshot
* Installation: Simply drop both files into your project and add #import "CCNode+Screenshot.h" were required.
*
* Supported : iOS4+, cocos2d 2.0, (Unofficial) cocos2d 1.0 (See Below)
* ARC : Works with ARC & Non-Arc
* Tested : iOS5 Simulator (All Devices)
* iPhone (Retina) 5.1
*
* Example:
* [self getScreenshot:^(UIImage *image){
* CCLOG(@"Saving Screenshot to Photo Album");
* UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);
* }];
*
* Misc:
* Any questions you can find me (@cocojoe) on the cocos2d forum: http://www.cocos2d-iphone.org/forum/
*/
#import "CCNode+Screenshot.h"
#import "CCDirector.h"
#import <objc/runtime.h>
static char SCREENSHOTBLOCK_KEY;
@implementation CCNode (Screenshot)
@dynamic completionBlock;
-(void) getScreenshot:(ScreenshotCompletionBlock) block;
{
objc_setAssociatedObject(self, &SCREENSHOTBLOCK_KEY, block, OBJC_ASSOCIATION_COPY_NONATOMIC);
// Will be black screen if not scheduled
[self scheduleOnce:@selector(screenshot:) delay:0];
}
#pragma mark Private API
-(void) screenshot:(ccTime) dt
{
// cocos2d 1.0, change 'view' to 'openGLView'
UIView * eagleView = (UIView*)[[CCDirector sharedDirector] view];
GLint backingWidth, backingHeight;
// Bind the color renderbuffer used to render the OpenGL ES view
// If your application only creates a single color renderbuffer which is already bound at this point,
// this call is redundant, but it is needed if you're dealing with multiple renderbuffers.
// Note, replace "_colorRenderbuffer" with the actual name of the renderbuffer object defined in your class.
// In Cocos2D the render-buffer is already binded (and it's a private property...).
// glBindRenderbufferOES(GL_RENDERBUFFER_OES, _colorRenderbuffer);
// Get the size of the backing CAEAGLLayer
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &backingWidth);
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &backingHeight);
NSInteger x = 0, y = 0, width = backingWidth, height = backingHeight;
NSInteger dataLength = width * height * 4;
GLubyte *data = (GLubyte*)malloc(dataLength * sizeof(GLubyte));
// Read pixel data from the framebuffer
glPixelStorei(GL_PACK_ALIGNMENT, 4);
glReadPixels(x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data);
// Create a CGImage with the pixel data
// If your OpenGL ES content is opaque, use kCGImageAlphaNoneSkipLast to ignore the alpha channel
// otherwise, use kCGImageAlphaPremultipliedLast
CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, data, dataLength, NULL);
CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
CGImageRef iref = CGImageCreate (
width,
height,
8,
32,
width * 4,
colorspace,
// Fix from Apple implementation
// (was: kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast).
kCGBitmapByteOrderDefault,
ref,
NULL,
true,
kCGRenderingIntentDefault
);
// OpenGL ES measures data in PIXELS
// Create a graphics context with the target size measured in POINTS
NSInteger widthInPoints, heightInPoints;
if (NULL != UIGraphicsBeginImageContextWithOptions)
{
// On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
// Set the scale parameter to your OpenGL ES view's contentScaleFactor
// so that you get a high-resolution snapshot when its value is greater than 1.0
CGFloat scale = eagleView.contentScaleFactor;
widthInPoints = width / scale;
heightInPoints = height / scale;
UIGraphicsBeginImageContextWithOptions(CGSizeMake(widthInPoints, heightInPoints), NO, scale);
}
CGContextRef cgcontext = UIGraphicsGetCurrentContext();
// UIKit coordinate system is upside down to GL/Quartz coordinate system
// Flip the CGImage by rendering it to the flipped bitmap context
// The size of the destination area is measured in POINTS
CGContextSetBlendMode(cgcontext, kCGBlendModeCopy);
CGContextDrawImage(cgcontext, CGRectMake(0.0, 0.0, widthInPoints, heightInPoints), iref);
// Retrieve the UIImage from the current context
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// Clean up
free(data);
CFRelease(ref);
CFRelease(colorspace);
CGImageRelease(iref);
// Block Execution
ScreenshotCompletionBlock completionBlock = objc_getAssociatedObject(self, &SCREENSHOTBLOCK_KEY);
completionBlock(image);
}
@end
并且这样做：
[myScene getScreenshot:^(UIImage *image){
// image will contain the screenshot...
}];
我可以用这个区域内的screnshot做任何我想做的事情但不在外面。我的意思是，我需要这个块来返回一个图像，比如
- (UIImage *) shot {
__block UIImage *screenshot = nil;
[myScene getScreenshot:^(UIImage *image){
// image will contain the screenshot...
screenshot = image;
}];
return screenshot;
}
目前这不起作用，因为线截止屏幕截图将在截屏之前运行，我不能把这条线放在块中。
我该如何解决这个问题？我还不熟练。
感谢。
现在假设我需要的是让这个块异步返回图像。
答案 0 :(得分：0)
最简单的解决方案是实现相同的模式，并将完成块暴露给调用者：
-(void) shotWithCompletionBlock:(ScreenshotCompletionBlock)completionBlock
{
[myScene getScreenshot:completionBlock];
}
或者，您可以通过让他传递通知目标来通知呼叫者（建议使用@protocol，为简洁起见省略）：
-(void) shotWithNotificationTarget:(id)target
{
if ([target respondsToSelector:@selector(heyYourScreenshotsReady:)])
{
[myScene getScreenshot:^(UIImage *image){
[target heyYourScreenshotsReady:image];
}];
}
}
答案 1 :(得分：0)
处理图像的代码 - 无论是什么 - 将转换为块。不要犹豫，将所需的任何代码放入块中，比如将其保存到文件中，将其发送到服务器，为其分配某个对象的属性，或者其他任何内容。该块就是为了处理这个问题。