iOS截取图片的一部分

UIImage
* imgeee = [UIImage
imageWithCGImage:CGImageCreateWithImageInRect([self.currentImageForCamera.image
CGImage],
CGRectMake(0,
0,
100,
100))];

- (UIImage
*)getPartOfImage:(UIImage
*)img rect:(CGRect)partRect{
   
CGImageRef imageRef = img.CGImage;

   
CGImageRef imagePartRef =
CGImageCreateWithImageInRect(imageRef, partRect);

   
UIImage *retImg = [UIImage
imageWithCGImage:imagePartRef];

   
CGImageRelease(imagePartRef);

   
return retImg;
}

#注释·这种模式会让图片旋转90°。

(UIImage )fixOrientation:(UIImage )aImage {

if (aImage.imageOrientation == UIImageOrientationUp) return aImage;

CGAffineTransform transform = CGAffineTransformIdentity;

switch (aImage.imageOrientation) { case UIImageOrientationDown: case UIImageOrientationDownMirrored: transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height); transform = CGAffineTransformRotate(transform, M_PI); break;

case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;

case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
default:
break;

[/code]
}

switch (aImage.imageOrientation) { case UIImageOrientationUpMirrored: case UIImageOrientationDownMirrored: transform = CGAffineTransformTranslate(transform, aImage.size.width, 0); transform = CGAffineTransformScale(transform, -1, 1); break;

case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
default:
break;

[/code]
}

CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height, CGImageGetBitsPerComponent(aImage.CGImage), 0, CGImageGetColorSpace(aImage.CGImage), CGImageGetBitmapInfo(aImage.CGImage)); CGContextConcatCTM(ctx, transform); switch (aImage.imageOrientation)
{ case UIImageOrientationLeft: case UIImageOrientationLeftMirrored: case UIImageOrientationRight: case UIImageOrientationRightMirrored:

CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
break;

default:
CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
break;

[/code]
}

CGImageRef cgimg = CGBitmapContextCreateImage(ctx); UIImage *img = [UIImage imageWithCGImage:cgimg]; CGContextRelease(ctx); CGImageRelease(cgimg); return img;

}