iphone - 更改 UIImage 按钮的颜色

Question

我想更改作为按钮放置在导航栏中的图像的颜色。我用来创建图像/按钮的代码是:

UIImage *btnGoImage = [UIImage imageNamed:@"settings_cog.png"];
UIButton *btnGoPre = [UIButton buttonWithType:UIButtonTypeCustom];
btnGoPre.bounds = CGRectMake( 0, 0, 30, 30 );
[btnGoPre setImage:btnGoImage forState:UIControlStateNormal];

[btnGoPre addTarget:self action:@selector(loginAction) 
forControlEvents:UIControlEventTouchUpInside];

UIBarButtonItem *btnGo = [[UIBarButtonItem alloc] initWithCustomView:btnGoPre];

如果我想将图像更改为红色(当前为灰色)。我该怎么做？谢谢!

Answer 1

这是一种有助于更改图像颜色的方法，您需要将图像和颜色作为输入变量传递，它将返回输出图像

-(UIImage *)imageNamed:(NSString *)name withColor:(UIColor *)color 
{
    // load the image
    UIImage *img = [UIImage imageNamed:name];

    // begin a new image context, to draw our colored image onto
    UIGraphicsBeginImageContext(img.size);

    // get a reference to that context we created
    CGContextRef context = UIGraphicsGetCurrentContext();

    // set the fill color
    [color setFill];

    // translate/flip the graphics context (for transforming from CG* coords to UI* coords
    CGContextTranslateCTM(context, 0, img.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);

    // set the blend mode to color burn, and the original image
    CGContextSetBlendMode(context, kCGBlendModeColorBurn);
    CGRect rect = CGRectMake(0, 0, img.size.width, img.size.height);
    CGContextDrawImage(context, rect, img.CGImage);

    // set a mask that matches the shape of the image, then draw (color burn) a colored rectangle
    CGContextClipToMask(context, rect, img.CGImage);
    CGContextAddRect(context, rect);
    CGContextDrawPath(context,kCGPathFill);

    // generate a new UIImage from the graphics context we drew onto
    UIImage *coloredImg = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    //return the color-burned image
    return coloredImg;
}

下面是如何调用这个方法的例子

yourImageView.image = [self imageNamed:@"yourImageName" withColor:[UIColor orangeColor]];