斯威夫特5

重绘图像的背景和填充颜色

extension UIImage {
  func withBackground(color: UIColor, fill fillColor: UIColor) -> UIImage {
    UIGraphicsBeginImageContextWithOptions(size, true, scale)
    
    guard let ctx = UIGraphicsGetCurrentContext(), let image = cgImage else { return self }
    defer { UIGraphicsEndImageContext() }
    
    ctx.concatenate(CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: size.height))
    
    let rect = CGRect(origin: .zero, size: size)
    
    // draw background
    ctx.setFillColor(color.cgColor)
    ctx.fill(rect)
    
    // draw image with fill color
    ctx.clip(to: rect, mask: image)
    ctx.setFillColor(fillColor.cgColor)
    ctx.fill(rect)
    
    return UIGraphicsGetImageFromCurrentImageContext() ?? self
  }
}

你可以在Swift 3中使用它，如果你有一个图像来替换清除按钮

func addTextfieldRightView(){

    let rightViewWidth:CGFloat = 30

    let viewMax = self.searchTxt.frame.height
    let buttonMax = self.searchTxt.frame.height - 16

    let buttonView = UIView(frame: CGRect(
        x: self.searchTxt.frame.width - rightViewWidth,
        y: 0,
        width: viewMax,
        height: viewMax))

    let myButton = UIButton(frame: CGRect(
        x: (viewMax - buttonMax) / 2,
        y: (viewMax - buttonMax) / 2,
        width: buttonMax,
        height: buttonMax))

    myButton.setImage(UIImage(named: "BlueClear")!, for: .normal)

    buttonView.addSubview(myButton)

    let clearPressed = UITapGestureRecognizer(target: self, action: #selector(SearchVC.clearPressed(sender:)))
    buttonView.isUserInteractionEnabled = true
    buttonView.addGestureRecognizer(clearPressed)

    myButton.addTarget(self, action: #selector(SearchVC.clearPressed(sender:)), for: .touchUpInside)

    self.searchTxt.rightView = buttonView
    self.searchTxt.rightViewMode = .whileEditing
}

这里有一个类别应该可以做到这一点

@interface UIImage(Overlay)
@end

@implementation UIImage(Overlay)

- (UIImage *)imageWithColor:(UIColor *)color1
{
        UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
        CGContextRef context = UIGraphicsGetCurrentContext();
        CGContextTranslateCTM(context, 0, self.size.height);
        CGContextScaleCTM(context, 1.0, -1.0);
        CGContextSetBlendMode(context, kCGBlendModeNormal);
        CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
        CGContextClipToMask(context, rect, self.CGImage);
        [color1 setFill];
        CGContextFillRect(context, rect);
        UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return newImage;
}
@end

所以你会这样做:

theImageView.image = [theImageView.image imageWithColor:[UIColor redColor]];

另外，对于以上的答案，在iOS 13及以后有一个干净的方法

let image = UIImage(named: "imageName")?.withTintColor(.white, renderingMode: .alwaysTemplate)

如果有人关心没有UIImageView的解决方案:

// (Swift 3)
extension UIImage {
    func tint(with color: UIColor) -> UIImage {
        var image = withRenderingMode(.alwaysTemplate)
        UIGraphicsBeginImageContextWithOptions(size, false, scale)
        color.set()

        image.draw(in: CGRect(origin: .zero, size: size))
        image = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        return image
    }
}

在iOS 13及以上版本中，你可以简单地使用

let image = UIImage(named: "Heart")?.withRenderingMode(.alwaysTemplate)
if #available(iOS 13.0, *) {
   imageView.image = image?.withTintColor(UIColor.white)
}