创建CMYK+alpha位图，将黑色映射到特定的CMYK颜色-CreateCMYK+alphabitmap,mappingblacktospecificCMYKcolor

Given this arched text image, black pixels on transparent background, with antialiasing

给定这个拱形文本图像,透明背景上的黑色像素,具有抗锯齿功能

I would ultimately like to have a CMYK rendering of this text, where every black pixel becomes a specific CMYK color, say magenta, or {72,36,9,28}, or whatever my customer specifies. The ultimate output will be PDF. Every transparent pixel needs to remain transparent, as there may be other PDF objects under the text.

我最终想要这个文本的CMYK渲染,其中每个黑色像素变成特定的CMYK颜色,比如品红色,或者{72,36,9,28},或者我的客户指定的任何颜色。最终输出将是PDF。每个透明像素都需要保持透明,因为文本下可能还有其他PDF对象。

I would be content with a CMYK+Alpha TIFF equivalent written to disk. Or, possibly, a System.Windows.Media.Imaging.Bitmapimage. Or something else.

我会满足于写入磁盘的CMYK + Alpha TIFF等价物。或者,可能是System.Windows.Media.Imaging.Bitmapimage。或者是其他东西。

My PDF library is ABCpdf.NET 10. I realize that System.Drawing does not support CMYK color format. I'm ok with other third party libraries; I'm already using AForge in another context in the library.

我的PDF库是ABCpdf.NET 10.我意识到System.Drawing不支持CMYK颜色格式。我和其他第三方图书馆一样好;我已经在库中的另一个上下文中使用了AForge。

I am not looking to do RGB to CMYK conversion, not even with a profile. I am not looking to do generic color replacement in a PDF. My customer will specify a definite CMYK target color, and I need to match it exactly; using color conversion on an RGB approximation is not okay.

我不打算做RGB到CMYK转换,甚至没有配置文件。我不打算在PDF中进行通用颜色替换。我的客户将指定一个明确的CMYK目标颜色,我需要完全匹配它;在RGB近似上使用颜色转换是不可行的。

I've flailed around with various things. The closest I got was to swap the colors while staying in RGB -- black becomes transparent, transparent becomes white -- and draw a filled magenta box under the image. That then draws white pixels where the text is not, and the magenta underneath shows through. Considered as a group, this ends up looking like warped magenta text on white. But anything sitting under the group does not show through. link

我已经挥舞着各种各样的东西。我得到的最接近的是交换颜色,同时保持RGB - 黑色变为透明,透明变为白色 - 并在图像下绘制一个填充的洋红色框。然后绘制白色像素,文本不是,下面的洋红色显示通过。被视为一个群体,这最终看起来像白色扭曲的洋红色文字。但是,任何坐在小组下面的东西都没有显示出来。链接

Any ideas?

1 个解决方案

using WebSupergoo.ABCpdf10;
using WebSupergoo.ABCpdf10.Objects;

namespace RecolorRenderedImage
{
    class Program
    {
        static void Main(string[] args)
        {
            using (Doc theDoc = new Doc()) {
                // this background image is there to prove that the text is not obscuring other pdf objects
                theDoc.AddImage("c:\\temp\\background-pic.jpg");

                // this is the black warped text
                string fullFilePath = "c:\\temp\\foobar.png";

                // read it into an XImage. Add to the doc, and retrieve the pixmap
                XReadOptions readOptiOns= new XReadOptions();
                XImage image = XImage.FromFile(fullFilePath, readOptions);
                int theID = theDoc.AddImageObject(image, true);
                int imageID = theDoc.GetInfoInt(theID, "XObject");
                PixMap thePM = (PixMap)theDoc.ObjectSoup[imageID];

                // recolor the pixmap temporary spot color space with the desired color (gold in this case)
                int spotColorID = theDoc.AddColorSpaceSpot("tempSpace", "24 44 100 2");
                ColorSpace theSP = (ColorSpace)theDoc.ObjectSoup[spotColorID];
                thePM.Recolor(theSP);

                // immediately recolor the pixmap back to CMYK
                ColorSpace theSP2 = new ColorSpace(theDoc.ObjectSoup, ColorSpaceType.DeviceCMYK);
                thePM.Recolor(theSP2);

                theDoc.Save("c:\\temp\\test.pdf");
            }
        }

    }
}