iphone - 在 iphone sdk 中使用 UIGraphicsBeginImageContextWithOptions 从原点捕获带有 -20 的图像

Question

我需要使用 UIGraphicsBeginImageContextWithOptions 来捕获图像我的要求是从 -20 从原点开始捕获

任何帮助将不胜感激

Answer 1

使用以下代码和 Import <QuartzCore/QuartzCore.h>。您也可以在捕获图像后使用此代码。因此，您可以从中删除不必要的部分。

    UIGraphicsBeginImageContext(self.view.frame.size);
    //or
    UIGraphicsBeginImageContextWithOptions(self.view.frame.size, NO, 0.0);//this will also give you scaling option and more better for resolution. 

    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

    CGImageRef ref = viewImage.CGImage;


    CGRect myImageArea = CGRectMake (20, 20,
                                     300, 100);// you define coordinates according your requirements.
    CGImageRef mySubimage = CGImageCreateWithImageInRect (ref, myImageArea);

    UIImage *yourfinalcapturedimage = [UIImage imageWithCGImage:mySubimage];// this will give you your required image.

希望对你有帮助..