DotSlashSlash DotSlashSlash - 1 year ago 111
Objective-C Question

How do I add a gradient to the text of a UILabel, but not the background?

hey, I want to be able to have a gradient fill on the text in a UILabel I know about CGGradient but i dont know how i would use it on a UILabel's text

i found this on google but i cant manage to get it to work

Answer Source

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Really useful answers by both Brad Larson and Bach. The second worked for me but it requires an image to be present in advance. I wanted something more dynamic so I combined both solutions into one:

  • draw the desired gradient on a UIImage
  • use the UIImage to set the color pattern

The result works and in the screenshot below you can see some Greek characters rendered fine too. (I have also added a stroke and a shadow on top of the gradient)

iOS stylized UILabel, the big brown fox

Here's the custom init method of my label along with the method that renders a gradient on a UIImage (part of the code for that functionality I got from a blog post I can not find now to reference it):

- (id)initWithFrame:(CGRect)frame text:(NSString *)aText {
    self = [super initWithFrame:frame];
    if (self) {
        self.backgroundColor = [UIColor clearColor];
        self.text = aText;

        self.textColor = [UIColor colorWithPatternImage:[self gradientImage]];

    return self;

- (UIImage *)gradientImage
    CGSize textSize = [self.text sizeWithFont:self.font];
    CGFloat width = textSize.width;         // max 1024 due to Core Graphics limitations
    CGFloat height = textSize.height;       // max 1024 due to Core Graphics limitations

    // create a new bitmap image context
    UIGraphicsBeginImageContext(CGSizeMake(width, height));

    // get context
    CGContextRef context = UIGraphicsGetCurrentContext();       

    // push context to make it current (need to do this manually because we are not drawing in a UIView)

    //draw gradient    
    CGGradientRef glossGradient;
    CGColorSpaceRef rgbColorspace;
    size_t num_locations = 2;
    CGFloat locations[2] = { 0.0, 1.0 };
    CGFloat components[8] = { 0.0, 1.0, 1.0, 1.0,  // Start color
                            1.0, 1.0, 0.0, 1.0 }; // End color
    rgbColorspace = CGColorSpaceCreateDeviceRGB();
    glossGradient = CGGradientCreateWithColorComponents(rgbColorspace, components, locations, num_locations);
    CGPoint topCenter = CGPointMake(0, 0);
    CGPoint bottomCenter = CGPointMake(0, textSize.height);
    CGContextDrawLinearGradient(context, glossGradient, topCenter, bottomCenter, 0);


    // pop context 

    // get a UIImage from the image context
    UIImage *gradientImage = UIGraphicsGetImageFromCurrentImageContext();

    // clean up drawing environment

    return  gradientImage;

I'll try to complete that UILabel subclass and post it.


The class is done and it's on my GitHub repository. Read about it here!

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