Chia UIImage làm đôi?

Question

Làm cách nào để chia nhỏ UIImage Trong nửa (xuống giữa) để nó có thể tạo ra hai hình ảnh?

Answer 1

Bạn có thể thử này,

UIImage *image = [UIImage imageNamed:@"yourImage.png"]; 
CGImageRef tmpImgRef = image.CGImage; 
CGImageRef topImgRef = CGImageCreateWithImageInRect(tmpImgRef, CGRectMake(0, 0, image.size.width, image.size.height/2.0)); 
UIImage *topImage = [UIImage imageWithCGImage:topImgRef]; 
CGImageRelease(topImgRef); 

CGImageRef bottomImgRef = CGImageCreateWithImageInRect(tmpImgRef, CGRectMake(0, image.size.height/2.0, image.size.width, image.size.height/2.0)); 
UIImage *bottomImage = [UIImage imageWithCGImage:bottomImgRef]; 
CGImageRelease(bottomImgRef); 

hy vọng điều này có thể giúp bạn, :)

Answer 2

Trả lời từ câu hỏi Stackoverflow khác. Source

UIImage *splitMeInTwo = [UIImage imageNamed:@"Star.png"]; 

UIImageView *original = [[UIImageView alloc] initWithImage:splitMeInTwo]; 
[self.view addSubview:original]; 
[original release]; 

// The size of each part is half the height of the whole image 
CGSize size = CGSizeMake([splitMeInTwo size].width, [splitMeInTwo size].height/2); 

// Create image-based graphics context for top half 
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0); 

// Draw into context, bottom half is cropped off 
//[image drawAtPoint:CGPointMake(0.0,0.0)]; 
[splitMeInTwo drawAtPoint:CGPointMake(0.0,0.0) blendMode:kCGBlendModeNormal alpha:1.0]; 

// Grab the current contents of the context as a UIImage 
// and add it to our array 
UIImage *top = UIGraphicsGetImageFromCurrentImageContext(); 
UIImageView *topV = [[UIImageView alloc] initWithImage:top]; 
CGRect frameTop = topV.frame; 
frameTop.origin.x += 360.0f; 
topV.frame = frameTop; 
[self.view addSubview:topV]; 
[topV release]; 

UIGraphicsEndImageContext(); 

Answer 3

- (void)splitImage:(UIImage *)image 
{ 
    CGFloat imgWidth = image.size.width/2; 
    CGFloat imgheight = image.size.height; 

    CGRect leftImgFrame = CGRectMake(0, 0, imgWidth, imgheight); 
    CGRect rightImgFrame = CGRectMake(imgWidth, 0, imgWidth, imgheight); 

    CGImageRef left = CGImageCreateWithImageInRect(image.CGImage, leftImgFrame); 
    CGImageRef right = CGImageCreateWithImageInRect(image.CGImage, rightImgFrame); 

    // These are the images we want! 
    UIImage *leftImage = [UIImage imageWithCGImage:left]; 
    UIImage *rightImage = [UIImage imageWithCGImage:right]; 

    // Don't forget to free the memory! 
    CGImageRelease(left); 
    CGImageRelease(right); 
} 

Answer 4

iOS 11, nhanh chóng cập nhật phiên bản 4.0 https://stackoverflow.com/users/893872/durul-dalkanat mà tôi nghĩ phải trung thực là tốt nhất :)

Điều này chia hình ảnh thành 4 phần

func splitImage(image2D: UIImage) -> [UIImage] { 
    let imgWidth = image2D.size.width/2 
    let imgHeight = image2D.size.height/2 
    var imgImages:[UIImage] = [] 

    let leftHigh = CGRect(x: 0, y: 0, width: imgWidth, height: imgHeight) 
    let rightHigh = CGRect(x: imgWidth, y: 0, width: imgHeight, height: imgHeight) 
    let leftLow = CGRect(x: 0, y: imgHeight, width: imgWidth, height: imgHeight) 
    let rightLow = CGRect(x: imgWidth, y: imgHeight, width: imgWidth, height: imgHeight) 

    let leftQH = image2D.cgImage?.cropping(to:leftHigh) 
    let rightHQ = image2D.cgImage?.cropping(to:rightHigh) 
    let leftQL = image2D.cgImage?.cropping(to:leftLow) 
    let rightQL = image2D.cgImage?.cropping(to:rightLow) 

    imgImages.append(UIImage(cgImage: leftQH!)) 
    imgImages.append(UIImage(cgImage: rightHQ!)) 
    imgImages.append(UIImage(cgImage: leftQL!)) 
    imgImages.append(UIImage(cgImage: rightQL!)) 

    return imgImages 
}