changing the color of image in iphone sdk

Question

I have a image & i want to change the color of that image through programatically.

Answer 1

CoreImage Color Filters work great for this kind of tasks - I find them slightly more straightforward than using the Core Graphic classes (CG...) : They work by allowing you to adjust the RGB and Alpha characteristics of the image I have been using them to change the white background of a QRCode to colored. RGBA of white is (1,1,1,1) in your case I believe you have to reverse the colour. Just check the CI documentation of Apple, there are a few dozen filters available CIColorMatrix is just one of them.

CIImage *beginImage = [CIImage imageWithCGImage:image.CGImage];

CIContext *context = [CIContext contextWithOptions:nil];

CIFilter *filtercd = [CIFilter filterWithName:@"CIColorMatrix"  //rgreen
                                keysAndValues: kCIInputImageKey, beginImage, nil];
[filtercd setValue:[CIVector vectorWithX:0 Y:1 Z:1 W:0] forKey:@"inputRVector"]; // 5
[filtercd setValue:[CIVector vectorWithX:1 Y:0 Z:1 W:0] forKey:@"inputGVector"]; // 6
[filtercd setValue:[CIVector vectorWithX:1 Y:1 Z:0 W:0] forKey:@"inputBVector"]; // 7
[filtercd setValue:[CIVector vectorWithX:0 Y:0 Z:0 W:1] forKey:@"inputAVector"]; // 8
[filtercd setValue:[CIVector vectorWithX:1 Y:1 Z:0 W:0] forKey:@"inputBiasVector"]; 
CIImage *doutputImage = [filtercd outputImage];


CGImageRef cgimgd = [context createCGImage:doutputImage fromRect:[doutputImage extent]];
UIImage *newImgd = [UIImage imageWithCGImage:cgimgd];

filterd.image = newImgd;

CGImageRelease(cgimgd);

Answer 2

UPDATE:

Use this method...

-(UIImage *)imageNamed:(NSString *)name withColor:(UIColor *)color {
    // load the image

    UIImage *img = [UIImage imageNamed:name];

    // begin a new image context, to draw our colored image onto
    UIGraphicsBeginImageContext(img.size);

    // get a reference to that context we created
    CGContextRef context = UIGraphicsGetCurrentContext();

    // set the fill color
    [color setFill];

    // translate/flip the graphics context (for transforming from CG* coords to UI* coords
    CGContextTranslateCTM(context, 0, img.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);

    // set the blend mode to color burn, and the original image
    CGContextSetBlendMode(context, kCGBlendModeColorBurn);
    CGRect rect = CGRectMake(0, 0, img.size.width, img.size.height);
    CGContextDrawImage(context, rect, img.CGImage);

    // set a mask that matches the shape of the image, then draw (color burn) a colored rectangle
    CGContextClipToMask(context, rect, img.CGImage);
    CGContextAddRect(context, rect);
    CGContextDrawPath(context,kCGPathFill);

    // generate a new UIImage from the graphics context we drew onto
    UIImage *coloredImg = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    //return the color-burned image
    return coloredImg;
}

Use it like bellow...

yourImageView.image = [self imageNamed:@"yourImageName" withColor:[UIColor orangeColor]];

hope this helpful to you.....

Answer 3

Here is the Swift version:

extension UIImage {

    func colorizeWith(color: UIColor) -> UIImage {
        UIGraphicsBeginImageContext(self.size)
        let context = UIGraphicsGetCurrentContext()
        color.setFill()
        CGContextTranslateCTM(context, 0, self.size.height)
        CGContextScaleCTM(context, 1.0, -1.0)

        // set the blend mode to color burn, and the original image
        CGContextSetBlendMode(context, kCGBlendModeNormal);
        let rect = CGRectMake(0, 0, self.size.width, self.size.height);
        CGContextDrawImage(context, rect, self.CGImage);

        // set a mask that matches the shape of the image, then draw (color burn) a colored rectangle
        CGContextClipToMask(context, rect, self.CGImage);
        CGContextAddRect(context, rect);
        CGContextDrawPath(context,kCGPathFill);

        // generate a new UIImage from the graphics context we drew onto
        let coloredImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        //return the color-burned image
        return coloredImage;
    }

}

Answer 4

As I've answered here iPhone - How do you color an image? in my opinion the best way to colorize an image from iOS 7 is by using

myImageView.image = [[UIImage imageNamed:@"myImage"] imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];

and then change the tintColor of the imageView or whatever contains the image.

Answer 5

You can try Ankish Jain's answer, it works for me.

theImageView.image = [theImageView.image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
[theImageView setTintColor:[UIColor redColor]];