Badged pin (eg for maps) using IB_Designable and IBInspectable

Badged pin

#import <UIKit/UIKit.h>

IB_DESIGNABLE @interface BadgedPin : UIView

@property (nonatomic, assign) IBInspectable CGFloat badgeDiameter;
@property (nonatomic, strong) IBInspectable UIColor *badgeColor;
@property (nonatomic, assign) IBInspectable CGFloat badgeStrokeWidth;
@property (nonatomic, strong) IBInspectable UIColor *fillColor;

@property (nonatomic, strong) IBInspectable NSString *imageName;

@end



#import "BadgedPin.h"

@interface BadgedPin()

@property (strong, nonatomic) UIImage *badge;
@property (strong, nonatomic) UIImage *underlyingImage;

@end

@implementation BadgedPin


- (void)drawRect:(CGRect)rect {
    CGRect bounds = self.bounds;
    
    CGFloat xposition = CGRectGetMaxX(bounds)/2 - self.badgeDiameter/2;
    CGFloat yposition = CGRectGetMaxY(bounds)/2 - self.badgeDiameter/2;
    
    CGPoint topLeftOfCentre = CGPointMake(xposition, yposition);
    CGRect rectangle = CGRectMake(topLeftOfCentre.x, topLeftOfCentre.y, self.badgeDiameter, self.badgeDiameter);
    UIBezierPath *outerCircle = [UIBezierPath bezierPathWithOvalInRect:rectangle];
    [self.badgeColor setStroke];
    [outerCircle setLineWidth:self.badgeStrokeWidth];
    [self.fillColor setFill];
    [outerCircle stroke];
    [outerCircle fill];
    
    [self.badge drawInRect:CGRectInset(rectangle, 4, 4)];
}

- (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        self.opaque = NO;
    }
    return self;
}

- (void)setImageName:(NSString *)imageName {
    _imageName = imageName;
    self.underlyingImage = [UIImage imageNamed:imageName];
    [self updateBadgeWithImage:self.underlyingImage];
}

- (void)prepareForInterfaceBuilder {
    NSBundle *currentBundle = [NSBundle bundleForClass:[self class]];
    self.underlyingImage = [UIImage imageNamed:self.imageName inBundle:currentBundle compatibleWithTraitCollection:self.traitCollection];
    [self updateBadgeWithImage:self.underlyingImage];
}

- (void)updateBadgeWithImage:(UIImage *)image {
    self.badge = [self tintImage:image withColor:self.badgeColor];
}

- (void)setBadgeColor:(UIColor *)badgeColor {
    _badgeColor = badgeColor;
    [self updateBadgeWithImage:self.underlyingImage];
}

- (UIImage *)tintImage:(UIImage *)image withColor:(UIColor *)color {
    // http://stackoverflow.com/questions/3514066/how-to-tint-a-transparent-png-image-in-iphone
    
    UIGraphicsBeginImageContextWithOptions (image.size, NO, [[UIScreen mainScreen] scale]); // for correct resolution on retina, thanks @MobileVet
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGContextTranslateCTM(context, 0, image.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);
    
    CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height);
    
    // image drawing code here
    // draw tint color
    CGContextSetBlendMode(context, kCGBlendModeNormal);
    [color setFill];
    CGContextFillRect(context, rect);
    
    // mask by alpha values of original image
    CGContextSetBlendMode(context, kCGBlendModeDestinationIn);
    CGContextDrawImage(context, rect, image.CGImage);
    UIImage *coloredImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return coloredImage;
}

@end