IOS如何在uiimageview中只截取图像

Question

我想只截取 imageview 中的图片。我尝试了以下代码，但它会截取 imageview 的屏幕截图。

CGRect grabRect = CGRectMake(self.vwBackup.frame.origin.x,self.vwBackup.frame.origin.y,self.vwBackup.frame.size.width,self.vwBackup.frame.size.height);

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
        UIGraphicsBeginImageContextWithOptions(grabRect.size, NO, [UIScreen mainScreen].scale);
    } else {
        UIGraphicsBeginImageContext(grabRect.size);
    }
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGContextTranslateCTM(ctx, -grabRect.origin.x, -grabRect.origin.y);
    [self.view.layer renderInContext:ctx];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
   // UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
    self.ImgEditableView.image=viewImage;

这里我附上了上面代码的截图：

Answer 1

if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
    UIGraphicsBeginImageContextWithOptions(self.displayImageView.bounds.size, NO, [UIScreen mainScreen].scale);
else
    UIGraphicsBeginImageContext(self.displayImageView.bounds.size);

[self.displayImageView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData * imgData = UIImagePNGRepresentation(image);
if(imgData)
{
    [imgData writeToFile:@"screenshot.png" atomically:YES];
}
else

    NSLog(@"error while taking screenshot");