ios - drawInRect 不读取/保留 UIImageView 变换

Question

我UIImageview在 drawInRect 中捏合、平移或旋转 a 时遇到问题，未保留变换。

如何在 drawInRect 中保留变换？

我试过这个但不行:(

- (UIImage*) combineImage:(UIImageView *)selectedImage withOverlay:(UIImageView *)overlayImage
{
    /* Identify the region that needs to be cropped */
    CGRect viewForImgFrame = self.viewForImg.frame;
    NSLog(@"view %@", NSStringFromCGRect(viewForImgFrame));
    NSLog(@"selectedImage Img value %@",selectedImage);
    NSLog(@"overlayImage Img value %@",overlayImage);
    CGSize newImageSize =self.viewForImg.frame.size;
    NSLog(@"CGSize %@",NSStringFromCGSize(newImageSize));
    UIGraphicsBeginImageContextWithOptions(newImageSize, NO, 0.0); //retina res

   //[self.viewForImg.layer renderInContext:UIGraphicsGetCurrentContext()];

    [selectedImage.image drawInRect:CGRectMake(0, 0, selectedImage.frame.size.width, selectedImage.frame.size.height)];

    CGContextConcatCTM(UIGraphicsGetCurrentContext(), overlayImage.transform);

    [overlayImage.image drawInRect:CGRectMake(overlayImage.frame.origin.x, overlayImage.frame.origin.y, overlayImage.frame.size.width, overlayImage.frame.size.height)];


    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    NSData *imgData =  UIImageJPEGRepresentation(image, 0.9); //UIImagePNGRepresentation ( image ); // get JPEG representation
    UIImage * imagePNG = [UIImage imageWithData:imgData]; // wrap UIImage around PNG representation
    UIGraphicsEndImageContext();
    return imagePNG;
}

任何意见都非常感谢。

Answer 1

你需要尝试

CGRectApplyAffineTransform(<#CGRect rect#>, <#CGAffineTransform t#>)

你的代码应该像

CGContextConcatCTM(UIGraphicsGetCurrentContext(), overlayImage.transform);
CGRect rect = CGRectMake(overlayImage.frame.origin.x, overlayImage.frame.origin.y, overlayImage.frame.size.width, overlayImage.frame.size.height);
CGRect transformedRect = CGRectApplyAffineTransform(rect, overlayImage.transform);
[overlayImage.image drawInRect:transformedRect];

Answer 2

原来 AutoresizingMask 改变了矩形大小

 [slider setAutoresizingMask:UIViewAutoresizingNone];