[求助]：请问acad的颜色索引和RGB的对应关系是怎样的

musicdancer

谢谢！

dubing

我试验过从CAD中抓图、然后转入FireWorks中进行颜色提取，发现非常有规律，我是从主界面中的颜色选取框中截取的，直接在CAD的ModelSpace中抓取的不准，提供一个例子

i_want_2

发现了什么规律？

cssanhui

最初由 musicdancer 发布
[B]谢谢！ [/B]

下载以下文件，就是你要的答案，不过你的爱心币也忒少了点吧，让我怎么好意思伸手喔。就这也要惩罚你一下，赶紧多发表言论，够30个爱心币才来免费下载吧。

masterhe

acdbGetRGB/acedGetRGB就应该可以取得你想要的

dubing

Answer
The following two functions will help you translate an RGB value to the nearest
equivalent AutoCAD Color Index. The function goes through all the AutoCAD
colours and searches the nearest one by comparing the differences from the given
RGB values to the RGB values corresponding to the 255 AutoCAD colors.


// This function returns the ACI color which is the "nearest" color to
// the color defined by the red, green and blue (RGB) values passed
// in argument.
int getNearestACI (const long red, const long green, const long blue) {
  long acirgb, r,g,b;
  long mindst = 2147483647L;
  long dst = 0;
  int minndx = 0;

  for ( int i = 1; i < 255; i++ ) {
      acirgb = acdbGetRGB ( i );
      r = ( acirgb & 0xffL );
      g = ( acirgb & 0xff00L ) >> 8;
      b = acirgb >> 16;

      dst = abs ( r-red) + abs ( g -green) + abs (b-blue);
      if ( dst < mindst ) {
        minndx = i;
        mindst = dst;
      }
  }
  return minndx;
}

// This function returns the ACI which has the "nearest" color to
// the color defined by rgb paramether of the function
// The rgb parameter is defined as follows:
// The low byte is the red, the next byte is the green, and
// the last byte is the blue RGB value -> 0x00BBGGRR
// The red, green, and blue bytes can have values from 0 to 255.
int getNearestACI (const unsigned long rgb) {
   long r = ( rgb & 0xffL );
   long g = ( rgb & 0xff00L ) >> 8;
   long b = rgb >> 16;;
   return getNearestACI (r, g, b);
}

Converting an AutoCAD Color Index (ACI) into its RGB color value can be done
using the ObjectARX function 'extern unsigned long acdbGetRGB(int color);'

Also same can be done by using the 'AcCmEntityColor '. For more information
and various member functions of 'AcCmEntityColor' look at Object Arx online help.