create UIImage programmatically for show marker on google map?

Question

In my app i integrated Google map sdk for iOS. iwant to show marker with sequence number on it.like The number of marker will be decided at run time so i can not simply put an mage for each marker, somehow i have to create it programmatically. I'v an image without sequence on it. my idea is to create an image using that image and write number on it while creating it. But don't know how. Any help would be appreciated.

Answer 1

Thanks to @knshn for giving me the link in comment. here is my solution

-(UIImage *)getImage :(UIImage *)icon stop:(NSString *)stopNumber color:(UIColor *)color
{
     // create label
     UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, icon.size.width,icon.size.height)];
     [label setText:stopNumber];
    [label setTextColor:color];
    [label setFont:[UIFont boldSystemFontOfSize:11]];
    label.textAlignment = NSTextAlignmentCenter;
     
     // use UIGraphicsBeginImageContext() to draw them on top of each other
     
     //start drawing
     UIGraphicsBeginImageContext(icon.size);
     
     //draw image
     [icon drawInRect:CGRectMake(0, 0, icon.size.width, icon.size.height)];
    
     //draw label
     [label drawTextInRect:CGRectMake((icon.size.width - label.frame.size.width)/2, -5, label.frame.size.width, label.frame.size.height)];
     
     //get the final image
     UIImage *resultImage  = UIGraphicsGetImageFromCurrentImageContext();
     
     UIGraphicsEndImageContext();
    return resultImage;
}

Use in Swift

func getImage(_ icon: UIImage?, stop stopNumber: String?, color: UIColor?) -> UIImage? {
    // create label
    let label = UILabel(frame: CGRect(x: 0, y: 0, width: icon?.size.width ?? 0.0, height: icon?.size.height ?? 0.0))
    label.text = stopNumber
    label.textColor = color
    label.font = FontFamily.Metropolis.semiBold.font(size: 15)
    label.textAlignment = .center
    
    //start drawing
    UIGraphicsBeginImageContext(icon?.size ?? CGSize.zero)
    
    //draw image
    icon?.draw(in: CGRect(x: 0, y: 0, width: icon?.size.width ?? 0.0, height: icon?.size.height ?? 0.0))
    
    //draw label
    label.drawText(in: CGRect(x: ((icon?.size.width ?? 0.0) - label.frame.size.width) / 2, y: -3, width: label.frame.size.width, height: label.frame.size.height))
    
    //get the final image
    let resultImage = UIGraphicsGetImageFromCurrentImageContext()
    
    UIGraphicsEndImageContext()
    return resultImage
}