ios - swift 改变图像的色调

Question

我是 swift 的新手，并试图从根本上实现这一点，这张图片给

这张图片 ->

我正在使用此代码 from here更改图像的色调但未获得所需的输出

func tint(image: UIImage, color: UIColor) -> UIImage
{
    let ciImage = CIImage(image: image)
    let filter = CIFilter(name: "CIMultiplyCompositing")

    let colorFilter = CIFilter(name: "CIConstantColorGenerator")
    let ciColor = CIColor(color: color)
    colorFilter.setValue(ciColor, forKey: kCIInputColorKey)
    let colorImage = colorFilter.outputImage

    filter.setValue(colorImage, forKey: kCIInputImageKey)
    filter.setValue(ciImage, forKey: kCIInputBackgroundImageKey)

    return UIImage(CIImage: filter.outputImage)!
}

如果这是一个菜鸟问题，抱歉。我能够在 javascript 中轻松地做到这一点，但不是很快。

Answer 1

您好，您可以通过以下方式使用它。首先，您使用的 UIImage 扩展需要一些更新。你可以复制下面的 Swift 3 代码

extension UIImage{
func tint(color: UIColor, blendMode: CGBlendMode) -> UIImage
{

    let drawRect = CGRect(x: 0,y: 0,width: size.width,height: size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, scale)
    color.setFill()
    UIRectFill(drawRect)
    draw(in: drawRect, blendMode: blendMode, alpha: 1.0)
    let tintedImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return tintedImage!
}
}

然后在您使用图像的 viewDidLoad 中例如我使用了来自 IBOutlet imageWood 的图像

    override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    self.imageWood.image = self.imageWood.image?.tint(color: UIColor.green, blendMode: .saturation)
}

你必须使用合适的颜色和图片

其他Extension我找到了

extension UIImage {

// colorize image with given tint color
// this is similar to Photoshop's "Color" layer blend mode
// this is perfect for non-greyscale source images, and images that have both highlights and shadows that should be preserved
// white will stay white and black will stay black as the lightness of the image is preserved
func tint(_ tintColor: UIColor) -> UIImage {

    return modifiedImage { context, rect in
        // draw black background - workaround to preserve color of partially transparent pixels
        context.setBlendMode(.normal)
        UIColor.black.setFill()
        context.fill(rect)

        // draw original image
        context.setBlendMode(.normal)
        context.draw(self.cgImage!, in: rect)

        // tint image (loosing alpha) - the luminosity of the original image is preserved
        context.setBlendMode(.color)
        tintColor.setFill()
        context.fill(rect)

        // mask by alpha values of original image
        context.setBlendMode(.destinationIn)
        context.draw(self.cgImage!, in: rect)
    }
}

// fills the alpha channel of the source image with the given color
// any color information except to the alpha channel will be ignored
func fillAlpha(_ fillColor: UIColor) -> UIImage {

    return modifiedImage { context, rect in
        // draw tint color
        context.setBlendMode(.normal)
        fillColor.setFill()
        context.fill(rect)

        // mask by alpha values of original image
        context.setBlendMode(.destinationIn)
        context.draw(self.cgImage!, in: rect)
    }
}


fileprivate func modifiedImage(_ draw: (CGContext, CGRect) -> ()) -> UIImage {

    // using scale correctly preserves retina images
    UIGraphicsBeginImageContextWithOptions(size, false, scale)
    let context: CGContext! = UIGraphicsGetCurrentContext()
    assert(context != nil)

    // correctly rotate image
    context.translateBy(x: 0, y: size.height);
    context.scaleBy(x: 1.0, y: -1.0);

    let rect = CGRect(x: 0.0, y: 0.0, width: size.width, height: size.height)

    draw(context, rect)

    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image!
}

这样使用

self.imageWood.image = self.imageWood.image?.tint(UIColor.purple.withAlphaComponent(1))