如何在ios中旋转遮罩图像

Question

我正在创建一个应用程序，它使用屏蔽的概念为图像提供纹理效果。用户还可以以任何角度旋转图像。

我的问题是，当我旋转图像时，屏蔽消失在这里是我用于屏蔽和旋转的代码。

-(IBAction)rotateImageView:(id)sender
{
    if (isRotated)
    {
        resultimg.image=rotateimage;
    }
    if([resultimg.image imageOrientation] == UIImageOrientationUp)
    {
        img = [UIImage imageWithCGImage:[img  CGImage]  scale:img.scale orientation:UIImageOrientationRight];

        rotateimage = [UIImage imageWithCGImage:[resultimg.image CGImage]  scale:resultimg.image.scale orientation:UIImageOrientationRight];
    }
    else if ([resultimg.image imageOrientation] == UIImageOrientationRight)
    {
        img = [UIImage imageWithCGImage:[img  CGImage]  scale:img.scale orientation:UIImageOrientationDown];

        rotateimage = [UIImage imageWithCGImage:[resultimg.image CGImage]  scale:resultimg.image.scale orientation:UIImageOrientationDown];
    }
    else if ([resultimg.image imageOrientation] == UIImageOrientationDown)
    {
        img = [UIImage imageWithCGImage:[img  CGImage]  scale:img.scale orientation:UIImageOrientationLeft];

        rotateimage= [UIImage imageWithCGImage:[resultimg.image CGImage]  scale:resultimg.image.scale orientation:UIImageOrientationLeft]; 
    }
    else if ([resultimg.image imageOrientation] == UIImageOrientationLeft)
    {
        img = [UIImage imageWithCGImage:[img  CGImage]  scale:img.scale orientation:UIImageOrientationUp];

        rotateimage = [UIImage imageWithCGImage:[resultimg.image CGImage]  scale:resultimg.image.scale orientation:UIImageOrientationUp];  
    }

    resultimg.image=rotateimage;
}

当图像指原始图像时，resultimg.image指的是包含带有蒙版图像效果的图像的图像视图。

对于屏蔽，我正在使用此代码。

-(void)masking
{
    int m=k ;

    UIImage *textureImage;

    textureImage = [UIImage imageNamed:[_imagearray2 objectAtIndex:m]];
    UIGraphicsBeginImageContextWithOptions(sizeR, YES, textureImage.scale);
    [textureImage drawInRect:CGRectMake(0.0, 0.0, sizeR.width, sizeR.height)];

    UIImage *bottomImage = UIGraphicsGetImageFromCurrentImageContext();

    upperImage= img;

    //upperImage =rotateimage;

    CGSize newSize = sizeR ;
    UIGraphicsBeginImageContext(newSize);

    [bottomImage drawInRect:CGRectMake(0.0, 0.0, sizeR.width, sizeR.height)];
    [upperImage drawInRect:CGRectMake(0.0, 0.0, sizeR.width, sizeR.height) blendMode:kCGBlendModeNormal alpha:0.7];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    resultimg.image=newImage;
}