截屏

(UIImage *) captureScreen {

    UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
    CGRect rect = [keyWindow bounds];
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    [keyWindow.layer renderInContext:context];  
    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return img;
}

如果要保存到相册:

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- (void)saveScreenshotToPhotosAlbum:(UIView *)view
    {
        UIImageWriteToSavedPhotosAlbum([self captureScreen], nil, nil, nil);
    } 
开发游戏时，往往会有这么一个需求：在某个成就达成或者破纪录时，需要截个屏，然后发送到微博上与好友/粉丝分享，虽然home ＋ 开机键组合可手动截屏，在Cocos2d有个CCRenderTexture类，借助该类可很容易实现代码截取功能。使用CCRenderTexture，我们可以截取游戏场景、某个Layer，甚至是精灵：

    /**游戏截图  
     *@param node 需要截取的控件  
    */  
    - (void)snapshotScreen:(CCNode*)node   
    {   
        //取得屏幕大小   
        CGSize winSize = [[CCDirector sharedDirector]winSize];   
        CCRenderTexture* renderTexture = [CCRenderTexture renderTextureWithWidth:winSize.width   
                                                                          height:winSize.height];   
        [renderTexture begin];   
        [node visit];   
        [renderTexture end];   
        [renderTexture cleanup];   
        UIImage *snapshot = [renderTexture getUIImageFromBuffer];   
        //把截图保存到相册里   
        UIImageWriteToSavedPhotosAlbum(snapshot, nil, nil, nil);   
    }  

  

如果游戏支持高清模式，上面代码截出来的图是960 * 640大小的，这个尺寸如果要上传到微博上，文件的大小可能会超出限制，那么在上传前可用先把截图大小缩小点如480*320，以减少图片体积：

    /** 调整图片大小*/  
    - (UIImage *) scaleFromImage: (UIImage *) image toSize: (CGSize) size   
    {   
        UIGraphicsBeginImageContext(size);   
        [image drawInRect:CGRectMake(0, 0, size.width, size.height)];   
        UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();   
        UIGraphicsEndImageContext();   
        return newImage;   
    }  

  

同时可以保存

[cpp] view plaincopy

    保存文件  
      
    UIImage *m_imgFore=......;  
      
    //png格式  
      
    NSData *imagedata=UIImagePNGRepresentation(m_imgFore);  
      
    //JEPG格式  
      
    //NSData *imagedata=UIImageJEPGRepresentation(m_imgFore,1.0);  
      
    NSArray*paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);  
      
    NSString *documentsDirectory=[paths objectAtIndex:0];   
      
    NSString *savedImagePath=[documentsDirectorystringByAppendingPathComponent:@"saveFore.png"];  
      
    [imagedata writeToFile:savedImagePath atomically:YES];  
      
    或者  
      
    [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:data attributes:nil];    将图片保存为PNG格式  
      
     [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.jpg"] contents:data attributes:nil];   将图片保存为JPEG格式  



如果不是cocos2D开发，则使用如下代码：

方法1：
[cpp] view plaincopy

    -(void)screenShots  
    {  
        CGSize imageSize = [[UIScreen mainScreen] bounds].size;  
        if (NULL != UIGraphicsBeginImageContextWithOptions) {  
            UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);  
        }  
        else  
        {  
            UIGraphicsBeginImageContext(imageSize);  
        }  
          
        CGContextRef context = UIGraphicsGetCurrentContext();  
          
        for (UIWindow * window in [[UIApplication sharedApplication] windows]) {  
            if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen]) {  
                CGContextSaveGState(context);  
                CGContextTranslateCTM(context, [window center].x, [window center].y);  
                CGContextConcatCTM(context, [window transform]);  
                CGContextTranslateCTM(context, -[window bounds].size.width*[[window layer] anchorPoint].x, -[window bounds].size.height*[[window layer] anchorPoint].y);  
                [[window layer] renderInContext:context];  
                  
                CGContextRestoreGState(context);  
            }  
        }  
          
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();  
          
        UIGraphicsEndImageContext();  
        UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);  
        NSLog(@"Suceeded!");  
    }  


(注意：方法1截图后会是竖屏，所以需要配合UIImage旋转的方法判断方向后旋转才能合适保存，见文章旋转翻转UIImage 不是UIImageView 适用于源图像的处理，例如截图后旋转)


所以再提供另外一方法：

方法2

[cpp] view plaincopy

    UIView *view = [[[[[UIApplication sharedApplication] windows] objectAtIndex:1] subviews] lastObject];//获得某个window的某个subView  
       
        NSInteger index = 0;//用来给保存的png命名  
        for (UIView *subView in [view subviews]) {//遍历这个view的subViews  
            if ([subView isKindOfClass:NSClassFromString(@"UIImageView")] || [subView isKindOfClass:NSClassFromString(@"UIThreePartButton")]) {//找到自己需要的subView  
                //支持retina高分的关键  
                if(UIGraphicsBeginImageContextWithOptions != NULL)  
                {  
                    UIGraphicsBeginImageContextWithOptions(subView.frame.size, NO, 0.0);  
                } else {  
                    UIGraphicsBeginImageContext(subView.frame.size);  
                }              
       
                //获取图像  
                [subView.layer renderInContext:UIGraphicsGetCurrentContext()];  
                UIImage *image = UIGraphicsGetImageFromCurrentImageContext();  
                UIGraphicsEndImageContext();  
       
                //保存图像  
                NSString *path = [NSHomeDirectory() stringByAppendingFormat:@"/%d.png",index];  
                if ([UIImagePNGRepresentation(image) writeToFile:path atomically:YES]) {  
                    index += 1;  
                    NSLog(@"Succeeded!");  
                }  
                else {  
                    NSLog(@"Failed!");  
                }  
            }  
        }

 
posted @ 2014-10-07 22:10  曦阳  阅读(301)  评论(0)  编辑  收藏  举报