將UIImage分為兩半

Question

我正在嘗試一種將UIImage裁剪到中間的方法。 我需要一種方法可以在一張照片的左中間裁剪我，而另一種方法可以在另一張照片的右中間裁剪我。

到目前為止，我只有風景的左側和肖像的右側：

if(firstImage.imageOrientation == UIImageOrientationUp){   //LANDSCAPE
        UIImage *image = firstImage;
        CGImageRef tmpImgRef = image.CGImage;
        CGImageRef topImgRef = CGImageCreateWithImageInRect(tmpImgRef, CGRectMake(0, 0, image.size.width /2.0, image.size.height));
        firstImage = [UIImage imageWithCGImage:topImgRef];
        CGImageRelease(topImgRef);
    }
    else{      //PORTRAIT
        UIImage *image = firstImage;
        CGImageRef tmpImgRef = image.CGImage;
        CGImageRef topImgRef = CGImageCreateWithImageInRect(tmpImgRef, CGRectMake(0, 0, image.size.width, image.size.height/2.0));
        firstImage = [UIImage imageWithCGImage:topImgRef scale:image.scale orientation:UIImageOrientationRight];
        CGImageRelease(topImgRef);
    }

我不太喜歡Core Graphics，有人可以幫我嗎？ 我現在想要的是一種告訴CGImageCreateWithImageInRect的方法，使我在景觀的右半部分而不是左半部分上修剪，在Portrait上我需要左半部分。

Answer 1

我沒有測試過，但我認為它可以工作：

//Portrait bottom half
UIGraphicsBeginImageContextWithOptions(CGSizeMake(image.width,image.height/2.0),NO,0);
[image drawAtPoint:CGPointMake(0, -image.size.height/2.0) blendMode:kCGBlendModeCopy alpha:1.0];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

//Landscape right half
UIGraphicsBeginImageContextWithOptions(CGSizeMake(image.width/2.0,image.height),NO,0);
[image drawAtPoint:CGPointMake(-image.size.width/2.0,0) blendMode:kCGBlendModeCopy alpha:1.0];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();