旋转UIImage的问题

我的代码如下。有谁知道发生了什么？旋转UIImage的问题

对不完整的信息。图像就消失了！

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { 

    UIImage *imCaptured = [info valueForKey:@"UIImagePickerControllerOriginalImage"]; 
    CGImageRef cgirCropped = CGImageCreateWithImageInRect(imCaptured.CGImage, CGRectMake(700.0f, 430.0f, 650.0f, 650.0f)); 
    UIImage *imCropped = [UIImage imageWithCGImage:cgirCropped]; 

    UIGraphicsBeginImageContext(imCropped.size); 
    CGContextRef cgcrRotation = UIGraphicsGetCurrentContext(); 

    switch (imCaptured.imageOrientation) { 
     case UIImageOrientationUp: 
      CGContextRotateCTM(cgcrRotation, (180 * M_PI/180)); 
      break; 
     case UIImageOrientationDown: 

      break; 
     case UIImageOrientationLeft: 

      break; 
     case UIImageOrientationRight: 
      CGContextRotateCTM(cgcrRotation, (90 * M_PI/180)); 
      break; 
    } 
    [imCropped drawAtPoint:CGPointMake(0.0f, 0.0f)]; 
    [imvPreview setImage:UIGraphicsGetImageFromCurrentImageContext()]; 
}

来源

2010-10-06 Paulo Ferreira

它帮助，如果你添加了什么错误（错误？旋转错误？什么都不做？） – cobbal 2010-10-06 20:34:13

我没有测试的代码，但我认为它围绕原点旋转，所以你需要翻译为好，这样的：

... 
case UIImageOrientationUp: 
     CGContextRotateCTM(cgcrRotation, (180 * M_PI/180)); 
     CGContextTranslateCTM(ctxt, -imCropped.size.width, -imCropped.size.height); 
     break; 
...

来源

2010-10-06 21:01:29

旋转UIImage的问题

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