参考链接：https://onevcat.com/2013/04/using-blending-in-ios/
需求：改变一张图片的颜色，让它根据所选的颜色显示不同颜色。
// UIImage+Tint.h
#import@interface UIImage (Tint)
- (UIImage *) imageWithTintColor:(UIColor *)tintColor;
- (UIImage *) imageWithGradientTintColor:(UIColor *)tintColor;
@end
// UIImage+Tint.m
#import "UIImage+Tint.h"
@implementation UIImage (Tint)
- (UIImage *) imageWithTintColor:(UIColor *)tintColor
{
return [self imageWithTintColor:tintColor blendMode:kCGBlendModeDestinationIn];
}
- (UIImage *) imageWithGradientTintColor:(UIColor *)tintColor
{
return [self imageWithTintColor:tintColor blendMode:kCGBlendModeOverlay];
}
- (UIImage *) imageWithTintColor:(UIColor *)tintColor blendMode:(CGBlendMode)blendMode
{
//We want to keep alpha, set opaque to NO; Use 0.0f for scale to use the scale factor of the device’s main screen.
UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0f);
[tintColor setFill];
CGRect bounds = CGRectMake(0, 0, self.size.width, self.size.height);
UIRectFill(bounds);
//Draw the tinted image in context
[self drawInRect:bounds blendMode:blendMode alpha:1.0f];
if (blendMode != kCGBlendModeDestinationIn) {
[self drawInRect:bounds blendMode:kCGBlendModeDestinationIn alpha:1.0f];
}
UIImage *tintedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return tintedImage;
}
@end
