Break down a picture in xcode for an iphone app - iphone

Question

Is there any way that I can have the user upload an image into the app, say for example a 50X150 pixels image, and I can break it into 3 50x50 pixel images?
If so, can someone help me to select certain pixels and break it into several images?
Thank you!

Answer 1

Use this code...
// In following method inRect:(CGRect)rect >>> this rect should be 50x50 or you can define according to your requirements..
- (UIImage *)imageFromImage:(UIImage *)image inRect:(CGRect)rect {
CGImageRef sourceImageRef = [image CGImage];
CGImageRef newImageRef = CGImageCreateWithImageInRect(sourceImageRef, rect);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef scale:1.0 orientation:image.imageOrientation];
CGImageRelease(newImageRef);
return newImage;
}
For more visit this reference..
Hope, this will help you...enjoy

Answer 2

Define a category on UIImage that gives you a great cropping method:
- (UIImage *)cropImageInRect:(CGRect)cropRect
{
CGImageRef image = CGImageCreateWithImageInRect(self.CGImage,cropRect);
UIImage *croppedImage = [UIImage imageWithCGImage:image];
CGImageRelease(image);
return croppedImage;
}
Now with this category you can easily do what you want to:
UIImage *original = ...;
UIImage left = [original cropImageInRect:CGRectMake(0.0, 0.0, 50.0, 50.0)];
UIImage center = [original cropImageInRect:CGRectMake(0.0, 50.0, 50.0, 50.0)];
UIImage right = [original cropImageInRect:CGRectMake(0.0, 100.0, 50.0, 50.0)];

Answer 3

I needed this, too. Added to a utils category method on UIImage:
// UIImage+Utls.h
#interface UIImage (UIImage_Utls)
- (UIImage *)subimageInRect:(CGRect)rect;
- (NSArray *)subimagesHorizontally:(NSInteger)count;
#end
// UIImage+Utls.m
#import "UIImage+Utls.h"
#implementation UIImage (UIImage_Utls)
- (UIImage *)subimageInRect:(CGRect)rect {
CGImageRef imageRef = CGImageCreateWithImageInRect([self CGImage], rect);
UIImage *answer = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return answer;
}
- (NSArray *)subimagesHorizontally:(NSInteger)count {
NSMutableArray *answer = [NSMutableArray arrayWithCapacity:count];
CGFloat width = self.size.width / count;
CGRect rect = CGRectMake(0.0, 0.0, width, self.size.height);
for (int i=0; i<count; i++) {
[answer addObject:[self subimageInRect:rect]];
rect = CGRectOffset(rect, width, 0.0);
}
return [NSArray arrayWithArray:answer];
}
#end