对灰度 NSImage（或 CIImage）进行着色

StackOverflow https://stackoverflow.com/questions/1413135

  •  06-07-2019
  •  | 
  •  

题

我有一个灰度图像，我想用它来绘制 Cocoa 控件。图像具有不同的灰度级别。在最暗的地方，我希望它绘制最暗的指定色调。我希望它在源图像是白色的地方是透明的。

基本上，我想重现在 iPhone 上的 UINavigationBar 中看到的tintColor 的行为。

到目前为止，我已经探索了几种选择：

  • 使用sourceover构图在灰度图像上绘制色调颜色 - >这需要一种非opaque的色彩颜色 - >结果比所需的要暗得多

  • 使用cimultiplyComposoposing cifilter为图像 - >我无法[ciimage drawatpoint：from rect：operation：aperion：ration：]仅绘制图像的一部分。nsimage->我偶尔会发生崩溃，我无法理解

  • 将灰度图像转换为蒙版。IE。黑色应该是不透明的。白色应该是透明的。灰色应该具有中间的 alpha 值。- >这似乎是最好的解决方案 - >尽我所能，我无法实现这一目标。

有帮助吗？

解决方案 3 

- (NSImage *)imageTintedWithColor:(NSColor *)tint 
{
    if (tint != nil) {
        NSSize size = [self size];
        NSRect bounds = { NSZeroPoint, size };
        NSImage *tintedImage = [[NSImage alloc] initWithSize:size];

        [tintedImage lockFocus];

        CIFilter *colorGenerator = [CIFilter filterWithName:@"CIConstantColorGenerator"];
        CIColor *color = [[[CIColor alloc] initWithColor:tint] autorelease];

        [colorGenerator setValue:color forKey:@"inputColor"];

        CIFilter *monochromeFilter = [CIFilter filterWithName:@"CIColorMonochrome"];
        CIImage *baseImage = [CIImage imageWithData:[self TIFFRepresentation]];

        [monochromeFilter setValue:baseImage forKey:@"inputImage"];     
        [monochromeFilter setValue:[CIColor colorWithRed:0.75 green:0.75 blue:0.75] forKey:@"inputColor"];
        [monochromeFilter setValue:[NSNumber numberWithFloat:1.0] forKey:@"inputIntensity"];

        CIFilter *compositingFilter = [CIFilter filterWithName:@"CIMultiplyCompositing"];

        [compositingFilter setValue:[colorGenerator valueForKey:@"outputImage"] forKey:@"inputImage"];
        [compositingFilter setValue:[monochromeFilter valueForKey:@"outputImage"] forKey:@"inputBackgroundImage"];

        CIImage *outputImage = [compositingFilter valueForKey:@"outputImage"];

        [outputImage drawAtPoint:NSZeroPoint
                        fromRect:bounds
                       operation:NSCompositeCopy
                        fraction:1.0];

        [tintedImage unlockFocus];  

        return [tintedImage autorelease];
    }
    else {
        return [[self copy] autorelease];
    }
}

- (NSImage*)imageCroppedToRect:(NSRect)rect
{
    NSPoint point = { -rect.origin.x, -rect.origin.y };
    NSImage *croppedImage = [[NSImage alloc] initWithSize:rect.size];

    [croppedImage lockFocus];
    {
        [self compositeToPoint:point operation:NSCompositeCopy];
    }
    [croppedImage unlockFocus];

    return [croppedImage autorelease];
}

其他提示

上述解决方案对我不起作用。但这个更简单的解决方案对我来说非常有用

- (NSImage *)imageTintedWithColor:(NSColor *)tint
{
    NSImage *image = [self copy];
    if (tint) {
        [image lockFocus];
        [tint set];
        NSRect imageRect = {NSZeroPoint, [image size]};
        NSRectFillUsingOperation(imageRect, NSCompositeSourceAtop);
        [image unlockFocus];
    }
    return image;
}

bluebamboo 答案的 Swift 实现：

func tintedImage(_ image: NSImage, tint: NSColor) -> NSImage {
    guard let tinted = image.copy() as? NSImage else { return image }
    tinted.lockFocus()
    tint.set()

    let imageRect = NSRect(origin: NSZeroPoint, size: image.size)
    NSRectFillUsingOperation(imageRect, .sourceAtop)

    tinted.unlockFocus()
    return tinted
}

扩展形式的 Swift 版本： 

extension NSImage {
    func tintedImageWithColor(color:NSColor) -> NSImage {
        let size        = self.size
        let imageBounds = NSMakeRect(0, 0, size.width, size.height)
        let copiedImage = self.copy() as! NSImage

        copiedImage.lockFocus()
        color.set()
        NSRectFillUsingOperation(imageBounds, .CompositeSourceAtop)
        copiedImage.unlockFocus()

        return copiedImage
    }
}

CIMultiplyCompositing 过滤器绝对是做到这一点的方法。如果崩溃了，您可以发布堆栈跟踪吗？我大量使用 CIFilters 并且没有崩溃问题。

//assume inputImage is the greyscale CIImage you want to tint

CIImage* outputImage = nil;

//create some green
CIFilter* greenGenerator = [CIFilter filterWithName:@"CIConstantColorGenerator"];
CIColor* green = [CIColor colorWithRed:0.30 green:0.596 blue:0.172];
[greenGenerator setValue:green forKey:@"inputColor"];
CIImage* greenImage = [greenGenerator valueForKey:@"outputImage"];

//apply a multiply filter
CIFilter* filter = [CIFilter filterWithName:@"CIMultiplyCompositing"];
[filter setValue:greenImage forKey:@"inputImage"];
[filter setValue:inputImage forKey:@"inputBackgroundImage"];
outputImage = [filter valueForKey:@"outputImage"];

[outputImage drawAtPoint:NSZeroPoint fromRect:NSRectFromCGRect([outputImage extent]) operation:NSCompositeCopy fraction:1.0];

我想用具有 Alpha 的色调颜色对图像进行着色，而不会看到图像的原始颜色显示出来。您可以按照以下方法执行此操作：

extension NSImage {
    func tinting(with tintColor: NSColor) -> NSImage {
        guard let cgImage = self.cgImage(forProposedRect: nil, context: nil, hints: nil) else { return self }

        return NSImage(size: size, flipped: false) { bounds in
            guard let context = NSGraphicsContext.current()?.cgContext else { return false }

            tintColor.set()
            context.clip(to: bounds, mask: cgImage)
            context.fill(bounds)

            return true
        }
    }
}

对于更细粒度的效果，您可以使用多项式颜色方法，使用我在下面建议的方法： 如何以不同的颜色显示旋转的 NSProgressIndicator？

许可以下： CC-BY-SA 和 归因
不隶属于 StackOverflow
scroll top