如何获取返回rgb，十六进制值的图像像素？ IOS

Question

I am new to ios so please be gentle...

I have an imageview which display selected image from the photo library .

I want to pick the color which i select touching on the image with its rgb and hex value.

Answer 1

I think you should try this method:

- (UIColor *)colorAtPosition:(CGPoint)position 
{
    CGRect sourceRect = CGRectMake(position.x, position.y, 1.f, 1.f);
    CGImageRef imageRef = CGImageCreateWithImageInRect(self.CGImage, sourceRect);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    unsigned char *buffer = malloc(4);
    CGBitmapInfo bitmapInfo = kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big;
    CGContextRef context = CGBitmapContextCreate(buffer, 1, 1, 8, 4, colorSpace, bitmapInfo);
    CGColorSpaceRelease(colorSpace);
    CGContextDrawImage(context, CGRectMake(0.f, 0.f, 1.f, 1.f), imageRef);
    CGImageRelease(imageRef);
    CGContextRelease(context);

    CGFloat r = buffer[0] / 255.f;
    CGFloat g = buffer[1] / 255.f;
    CGFloat b = buffer[2] / 255.f;
    CGFloat a = buffer[3] / 255.f;

   free(buffer);

   return [UIColor colorWithRed:r green:g blue:b alpha:a];
}

or try this one:

http://www.markj.net/iphone-uiimage-pixel-color/

This is pretty cool approach.