can i crop image by coordinates like (10,10,320,312)?

问题

Goal : How Crop a image after zooming. can i crop image after zooming at predefined coordinates like (10,10,320,312). my UIImageView has this size?

I have a UIImageView in a UIScrollView and I can zoom my image. I wants after zooming when I press cropButton the image which is displaying in UIImage is cropped. I wants size of image equal to UIImageView size.

thanks !!

before zooming

after zoom and crop

my code is here.

-(void)cropButtonClicked
{   
    //Calculate the required area from the scrollview
    CGRect visibleRect;
    float scale = 1.0f/scroll.zoomScale;
    visibleRect.origin.x = scroll.contentOffset.x * scale;
    visibleRect.origin.y = scroll.contentOffset.y * scale;
    visibleRect.size.width = scroll.bounds.size.width * scale;
    visibleRect.size.height = scroll.bounds.size.height * scale;

    UIImage *image = [self imageByCropping:imageView.image toRect:visibleRect];

    imageView.image=image;


}


- (UIImage*)imageByCropping:(UIImage *)myImage toRect:(CGRect)cropToArea{
CGImageRef cropImageRef = CGImageCreateWithImageInRect(myImage.CGImage, cropToArea);
UIImage* cropped = [UIImage imageWithCGImage:cropImageRef];

CGImageRelease(cropImageRef);
return cropped;
}
I use this logic.. Am I RIGHT? (May be i have to check my ScrollView programming)

回答1:

May this code use full for you..!!

CGSize itemSize = CGSizeMake(newWidth, newHeight);<br>
UIGraphicsBeginImageContextWithOptions(itemSize, NO, 0);<br>
CGRect imageRect = CGRectMake(0, 0, newWidth, newHeight);<br>
[image drawInRect:imageRect];<br>
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();<br>
UIGraphicsEndImageContext();

来源：https://stackoverflow.com/questions/11305606/can-i-crop-image-by-coordinates-like-10-10-320-312

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iphone

ios

crop