how to crop image in to pieces programmatically

后端 未结 4 1329
天涯浪人
天涯浪人 2020-11-27 06:35

I need to divide an image into 9 pieces programmatically. Any suggestions on how to do this?

相关标签:
4条回答
  • 2020-11-27 07:09

    There are many ways to slice and dice an image but here is one. It uses Quartz to cut an image into 9 equal-sized fractions. Notice it does not handle rotated images (by that I mean images with imageOrientation!=0) but it should get you started:

    +(NSArray *)splitImageInTo9:(UIImage *)im{
        CGSize size = [im size];
        NSMutableArray *arr = [[NSMutableArray alloc] initWithCapacity:9];
        for (int i=0;i<3;i++){
            for (int j=0;j<3;j++){
                CGRect portion = CGRectMake(i * size.width/3.0, j * size.height/3.0, size.width/3.0, size.height/3.0);
                UIGraphicsBeginImageContext(portion.size);
                CGContextRef context = UIGraphicsGetCurrentContext();
                CGContextScaleCTM(context, 1.0, -1.0);
                CGContextTranslateCTM(context, 0, -portion.size.height);
                CGContextTranslateCTM(context, -portion.origin.x, -portion.origin.y);
                CGContextDrawImage(context,CGRectMake(0.0, 0.0,size.width,  size.height), im.CGImage);
                [arr addObject:UIGraphicsGetImageFromCurrentImageContext()];
                UIGraphicsEndImageContext();
    
    
            }
        }
        return [arr autorelease];
    
    }
    

    The output will be an array of the 9 images each of size (with/3, height/3)

    0 讨论(0)
  • 2020-11-27 07:12

    The code below is also a solution that detects the piece of the picture that was tapped on. The idea is to take a UIImage and use CGImageCreateWithImageInRect to crop out pieces. From the cropped piece create a new UIImage and place it in a UIImageView. In order to get the tap gesture to work I had to place the UIImageView in a UIView. Finally, provide the gesture and a unique tag so that the piece can be identified when tapped on.

    - (void)loadView {
        UIView* root = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
        UIImage* whole = [UIImage imageNamed:@"whole.jpg"]; //I know this image is 300x300
    
        int partId = 0;
        for (int x=0; x<=200; x+=100) {
            for(int y=0; y<=200; y+=100) {
                CGImageRef cgImg = CGImageCreateWithImageInRect(whole.CGImage, CGRectMake(x, y, 100, 100));
                UIImage* part = [UIImage imageWithCGImage:cgImg];
                UIImageView* iv = [[UIImageView alloc] initWithImage:part];
    
                UIView* sView = [[UIView alloc] initWithFrame:CGRectMake(200-x, 200-y, 100, 100)];
                [sView addSubview:iv];
                [iv release];
    
                UITapGestureRecognizer* tap = [[UITapGestureRecognizer alloc] initWithTarget:self
                                                                                      action:@selector(tap:)];
                tap.numberOfTapsRequired = 1;
                [sView addGestureRecognizer:tap];
                [tap release];
    
                sView.tag = partId;
    
                [root addSubview:sView];
                [sView release];
                partId++;
                CGImageRelease(cgImg);
            }
        }
    
        self.view = root;
    }
    
    - (void)tap:(UITapGestureRecognizer*)gesture
    {
        NSLog(@"image tap=%d", gesture.view.tag);
    }
    
    0 讨论(0)
  • 2020-11-27 07:16

    If you want the parts of the image will be organized you need to use some UIImageView in the final view.. just take a look at this code :

        UIImage* whole = [UIImage imageNamed:@"permanent_cosmetics_pretty.jpg"];
        int partId = 0;     
        for (int x=0; x<=300; x+=100) {
          for(int y=0; y<=300; y+=100) { 
    
            CGImageRef cgImg = CGImageCreateWithImageInRect(whole.CGImage, CGRectMake(x, y, 100, 100));
            UIImage* part = [UIImage imageWithCGImage:cgImg];           
            UIImageView* iv = [[UIImageView alloc] initWithImage:part];                         
    
            switch (partId) {
                case 0:
                    self.part1.image=iv.image;
                    break;
                case 1:
                    self.part2.image=iv.image;
                    break;
                case 2:
                    self.part3.image=iv.image;
                    break;
                case 3:
                    self.part4.image=iv.image;
                    break;
                case 4:
                    self.part5.image=iv.image;
                    break;
                case 5:
                    self.part6.image=iv.image;
                    break;
                case 6:
                    self.part7.image=iv.image;
                    break;
                case 7:
                    self.part8.image=iv.image;
                    break;
                case 8:
                    self.part9.image=iv.image;
                    break;
                case 9:
                    self.part10.image=iv.image;
                    break;
                case 10:
                    self.part11.image=iv.image;
                    break;
                case 11:
                    self.part12.image=iv.image;
                    break;
                default:
                    break;
            }               
            [iv release];               
            partId++;
            NSLog(@"part id = %d",partId);
            }
       }
    
      [self.view addSubview:self.finalView];    
    
    0 讨论(0)
  • 2020-11-27 07:21

    Following code slice image based on parameters, add borders and displays:

    -(NSMutableArray *)getImagesFromImage:(UIImage *)image withRow:(NSInteger)rows           withColumn:(NSInteger)columns{
      NSMutableArray *images = [NSMutableArray array];
      CGSize imageSize = image.size;
      CGFloat xPos = 0.0, yPos = 0.0;
      CGFloat width = imageSize.width/rows;
      CGFloat height = imageSize.height/columns;
      for (int y = 0; y < columns; y++) {
        xPos = 0.0;
        for (int x = 0; x < rows; x++) {
    
            CGRect rect = CGRectMake(xPos, yPos, width, height);
            CGImageRef cImage = CGImageCreateWithImageInRect([image CGImage],  rect);
    
            UIImage *dImage = [[UIImage alloc] initWithCGImage:cImage];
            UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(x*width, y*height, width, height)];
            [imageView setImage:dImage];
            [imageView.layer setBorderColor:[[UIColor blackColor] CGColor]];
            [imageView.layer setBorderWidth:1.0];
            [self.view addSubview:imageView];
            [images addObject:dImage];
            xPos += width;
        }
        yPos += height;
    }
    return images;
    }
    

    Project download link: https://github.com/bpolat/Image-Slicer

    Sample Usage and Result:

    [self getImagesFromImage:[UIImage imageNamed:@"1.png"] withRow:4 withColumn:4];

    enter image description here

    0 讨论(0)
提交回复
热议问题