iOS實現截屏 併合適保存

開發遊戲時，往往會有這麼一個需求：在某個成就達成或者破紀錄時，需要截個屏，然後發送到微博上與好友/粉絲分享，雖然home ＋ 開機鍵組合可手動截屏，在Cocos2d有個CCRenderTexture類，藉助該類可很容易實現代碼截取功能。使用CCRenderTexture，我們可以截取遊戲場景、某個Layer，甚至是精靈：

/**遊戲截圖
 *@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];
    //把截圖保存到相冊裏
    UIImageWriteToSavedPhotosAlbum(snapshot, nil, nil, nil);
}

  

如果遊戲支持高清模式，上面代碼截出來的圖是960 * 640大小的，這個尺寸如果要上傳到微博上，文件的大小可能會超出限制，那麼在上傳前可用先把截圖大小縮小點如480*320，以減少圖片體積：

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

  

同時可以保存

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];    將圖片保存爲PNG格式

 [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.jpg"] contents:data attributes:nil];   將圖片保存爲JPEG格式

如果不是cocos2D開發，則使用如下代碼：

方法1：

-(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截圖後會是豎屏，所以需要配合UIImage旋轉的方法判斷方向後旋轉才能合適保存，見文章旋轉翻轉UIImage 不是UIImageView 適用於源圖像的處理，例如截圖後旋轉)

所以再提供另外一方法：

方法2

UIView *view = [[[[[UIApplication sharedApplication] windows] objectAtIndex:1] subviews] lastObject];//獲得某個window的某個subView

    NSInteger index = 0;//用來給保存的png命名
    for (UIView *subView in [view subviews]) {//遍歷這個view的subViews
        if ([subView isKindOfClass:NSClassFromString(@"UIImageView")] || [subView isKindOfClass:NSClassFromString(@"UIThreePartButton")]) {//找到自己需要的subView
            //支持retina高分的關鍵
            if(UIGraphicsBeginImageContextWithOptions != NULL)
            {
                UIGraphicsBeginImageContextWithOptions(subView.frame.size, NO, 0.0);
            } else {
                UIGraphicsBeginImageContext(subView.frame.size);
            }

            //獲取圖像
            [subView.layer renderInContext:UIGraphicsGetCurrentContext()];
            UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
            UIGraphicsEndImageContext();

            //保存圖像
            NSString *path = [NSHomeDirectory() stringByAppendingFormat:@"/%d.png",index];
            if ([UIImagePNGRepresentation(image) writeToFile:path atomically:YES]) {
                index += 1;
                NSLog(@"Succeeded!");
            }
            else {
                NSLog(@"Failed!");
            }
        }
    }