改变UIImage颜色

Question

我试图改变UIImage的颜色.我的代码:

-(UIImage *)coloredImage:(UIImage *)firstImage withColor:(UIColor *)color {
    UIGraphicsBeginImageContext(firstImage.size);

    CGContextRef context = UIGraphicsGetCurrentContext();
    [color setFill];

    CGContextTranslateCTM(context, 0, firstImage.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);

    CGContextSetBlendMode(context, kCGBlendModeCopy);
    CGRect rect = CGRectMake(0, 0, firstImage.size.width, firstImage.size.height);
    CGContextDrawImage(context, rect, firstImage.CGImage);

    CGContextClipToMask(context, rect, firstImage.CGImage);
    CGContextAddRect(context, rect);
    CGContextDrawPath(context,kCGPathElementMoveToPoint);

    UIImage *coloredImg = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return coloredImg;
}

这段代码有效,但获得的图像不是很好:返回图像的边界像素是间歇性的,不像我的第一张图像那么平滑.我该如何解决这个问题？

Answer 1

从iOS 7开始,这是最简单的方法.

Objective-C的:

theImageView.image = [theImageView.image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
[theImageView setTintColor:[UIColor redColor]];

Swift 2.0:

theImageView.image = theImageView.image?.imageWithRenderingMode(.AlwaysTemplate) 
theImageView.tintColor = UIColor.magentaColor()

Swift 4.0:

theImageView.image = theImageView.image?.withRenderingMode(.alwaysTemplate) 
theImageView.tintColor = .magenta

故事板:

首先将图像配置为资源中的模板(在右侧栏上 - 渲染为).然后图像的颜色将是应用的色调颜色.

Answer 2

这几乎是上面的答案,但略有缩短.这仅将图像作为遮罩,并且实际上不会"乘以"或着色图像.

目标C:

    UIColor *color = <# UIColor #>;
    UIImage *image = <# UIImage #>;// Image to mask with
    UIGraphicsBeginImageContextWithOptions(image.size, NO, image.scale);
    CGContextRef context = UIGraphicsGetCurrentContext();
    [color setFill];
    CGContextTranslateCTM(context, 0, image.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);
    CGContextClipToMask(context, CGRectMake(0, 0, image.size.width, image.size.height), [image CGImage]);
    CGContextFillRect(context, CGRectMake(0, 0, image.size.width, image.size.height));

    UIImage *coloredImg = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

迅速:

    let color: UIColor = <# UIColor #>
    let image: UIImage = <# UIImage #> // Image to mask with
    UIGraphicsBeginImageContextWithOptions(image.size, false, image.scale)
    let context = UIGraphicsGetCurrentContext()
    color.setFill()
    context?.translateBy(x: 0, y: image.size.height)
    context?.scaleBy(x: 1.0, y: -1.0)
    context?.clip(to: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height), mask: image.cgImage!)
    context?.fill(CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
    let coloredImg = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

Answer 3

从iOS 10开始，您可以使用UIGraphicsImageRenderer：

extension UIImage {

    func colored(_ color: UIColor) -> UIImage {
        let renderer = UIGraphicsImageRenderer(size: size)
        return renderer.image { context in
            color.setFill()
            self.draw(at: .zero)
            context.fill(CGRect(x: 0, y: 0, width: size.width, height: size.height), blendMode: .sourceAtop)
        }
    }

}

Answer 4

另一种着色图像的方法是简单地将其乘以恒定颜色.有时,这是优选的,因为它不会"提升"黑色区域的颜色值; 它使图像中的相对强度保持不变.使用叠加作为色调往往会使对比度变平.

这是我使用的代码:

UIImage *MultiplyImageByConstantColor( UIImage *image, UIColor *color ) {

    CGSize backgroundSize = image.size;
    UIGraphicsBeginImageContext(backgroundSize);

    CGContextRef ctx = UIGraphicsGetCurrentContext();

    CGRect backgroundRect;
    backgroundRect.size = backgroundSize;
    backgroundRect.origin.x = 0;
    backgroundRect.origin.y = 0;

    CGFloat r,g,b,a;
    [color getRed:&r green:&g blue:&b alpha:&a];
    CGContextSetRGBFillColor(ctx, r, g, b, a);
    CGContextFillRect(ctx, backgroundRect);

    CGRect imageRect;
    imageRect.size = image.size;
    imageRect.origin.x = (backgroundSize.width - image.size.width)/2;
    imageRect.origin.y = (backgroundSize.height - image.size.height)/2;

    // Unflip the image
    CGContextTranslateCTM(ctx, 0, backgroundSize.height);
    CGContextScaleCTM(ctx, 1.0, -1.0);

    CGContextSetBlendMode(ctx, kCGBlendModeMultiply);
    CGContextDrawImage(ctx, imageRect, image.CGImage);

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return newImage;
}

Swift版本

extension UIImage{

    static func multiplyImageByConstantColor(image:UIImage,color:UIColor)->UIImage{
        let backgroundSize = image.size
        UIGraphicsBeginImageContext(backgroundSize)

        let ctx = UIGraphicsGetCurrentContext()

        var backgroundRect=CGRect()
        backgroundRect.size = backgroundSize
        backgroundRect.origin.x = 0
        backgroundRect.origin.y = 0

        var r:CGFloat
        var g:CGFloat
        var b:CGFloat
        var a:CGFloat
        color.getRed(&r, green: &g, blue: &b, alpha: &a)
        CGContextSetRGBFillColor(ctx, r, g, b, a)
        CGContextFillRect(ctx, backgroundRect)

        var imageRect=CGRect()
        imageRect.size = image.size
        imageRect.origin.x = (backgroundSize.width - image.size.width)/2
        imageRect.origin.y = (backgroundSize.height - image.size.height)/2

        // Unflip the image
        CGContextTranslateCTM(ctx, 0, backgroundSize.height)
        CGContextScaleCTM(ctx, 1.0, -1.0)

        CGContextSetBlendMode(ctx, .Multiply)
        CGContextDrawImage(ctx, imageRect, image.CGImage)

        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage
    }
}

Answer 5

Swift 4.2 解决方案

extension UIImage {
    func withColor(_ color: UIColor) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size, false, scale)
        guard let ctx = UIGraphicsGetCurrentContext(), let cgImage = cgImage else { return self }
        color.setFill()
        ctx.translateBy(x: 0, y: size.height)
        ctx.scaleBy(x: 1.0, y: -1.0)
        ctx.clip(to: CGRect(x: 0, y: 0, width: size.width, height: size.height), mask: cgImage)
        ctx.fill(CGRect(x: 0, y: 0, width: size.width, height: size.height))
        guard let colored = UIGraphicsGetImageFromCurrentImageContext() else { return self }
        UIGraphicsEndImageContext()
        return colored
    }
}

// Usage:
// let redImage = UIImage().withColor(.red)

Answer 6

在Swift 3.0中

imageView.image? = (imageView.image?.withRenderingMode(.alwaysTemplate))!
imageView.tintColor = UIColor.magenta

在Swift 2.0中

yourImage.image? = (yourImage.image?.imageWithRenderingMode(.AlwaysTemplate))!
yourImage.tintColor = UIColor.magentaColor()

享受Swift先锋