iOS截取图片的一部分

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

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- (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°。

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2. (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;
   
   
   

   }

   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;
   
   
   

   }

   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;
   
   
   

   }

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

}