【第10期】iOS修改图片的颜色

关注微信公众号【科技小弟】，了解第一手iOS小知识。

今天介绍一下怎么修改图片的颜色。

.h文件代码：
科技小弟(https://www.jianshu.com/u/23c527245f22)

#import <UIKit/UIKit.h>

@interface UIImage (YYChangePictureColor)

/**
 *  修改图片颜色（如何使用：[[UIImage imageNamed:@"image"] imageWithTintColor:[UIColor orangeColor]]; ）
 *
 *  @param tintColor 指定颜色
 *
 *  @return 图片
 */
- (UIImage *)imageWithTintColor:(UIColor *)tintColor;
- (UIImage *)imageWithGradientTintColor:(UIColor *)tintColor;​

@end

.m文件代码：

#import "UIImage+YYChangePictureColor.h"​

@implementation UIImage (YYChangePictureColor)

- (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

怎么使用？我们先找一张图片：

1

这是一个白色图标，用于后退按钮，如果我们想把它改成其他颜色呢？

比如我们想把它改成蓝色，调用：

[_backButton setImage:[[UIImage imageNamed:@"common_back"] imageWithTintColor:[UIColor blueColor]] forState:UIControlStateNormal];

结果展示：

2

看，它已经变成蓝色了，完美！