linux - 将 RGB PDF 转换为 CMYK 在 Linux 上保持 100% K(黑色)和 100% M(洋红色)

Question

这与:

Converting (any) PDF to black (K)-only CMYK

你好

首先请原谅我的英语。

这个相关链接对我的问题有 50% 的解决方案。唯一剩下的就是我还需要洋红色为 100% 洋红色。

这里是场景:

我有一个这样的 html:

<font color="magenta">Hello </font>
<font color="#000000"> World </font>

1- 我将其转换为:

/usr/bin/wkhtmltopdf file.html output1.pdf

2 - 将黑色文本转换为 100% k:

gs \
   -dNOPAUSE \
   -dBATCH \
   -sDEVICE=ps2write \
   -sOutputFile=output1.ps \
    output1.pdf

# PS to PDF using replacement function in HackRGB-cmyk-inv.ps
gs \
   -dNOPAUSE \
   -dBATCH \
   -sDEVICE=pdfwrite \
   -sOutputFile=output2.pdf \
    /HackRGB-cmyk-inv.ps \
    output1.ps

现在我有一个 output2.pdf，其中黑色文本是 100% K 但洋红色不是 100% M...

这里是HackRGB-cmyk-ink.ps(postscript)的内容供引用:

%!
/oldsetrgbcolor /setrgbcolor load def
/setrgbcolor {
(in replacement setrgbcolor\n) print
                                %% R G B
  1 index 1 index       %% R G B G B
  eq {                  %%
     2 index 1 index    %% R G B R B
     eq {
                        %% Here if R = G = B
      pop pop           %% remove two values
      % setgray % "replace the 'setgray' with":
      0 0 0 4 -1 roll % setcmykcolor
      -1 mul          %% obtain -R on top of stack
      1 add           %% obtain 1-R on top of stack
      setcmykcolor    %% now set(cmykcolor) K (as 1-R)
     } {
       oldsetrgbcolor   %% set the RGB values
     } ifelse
  }{
    oldsetrgbcolor      %% Set the RGB values
  }ifelse

} bind def
/oldsetgray /setgray load def
/setgray {
(in replacement setgray\n) print
  % == % debug: pop last element and print it
  % here we're at a gray value;
  % http://www.tailrecursive.org/postscript/operators.html#setcymkcolor
  % setgray: "gray-value must be a number from 0 (black) to 1 (white)."
  % setcymkcolor: "The components must be between 0 (none) to 1 (full)."
  % so convert here again:
  0 0 0 4 -1 roll % push CMY:000 after Gray and roll down,
                  % so top of stack becomes
                  % ...:C:M:Y:Gray
  -1 mul          %% obtain -Gray on top of stack
  1 add           %% obtain 1-Gray on top of stack
  setcmykcolor    %% now set(cmykcolor) K (as 1-Gray)
} bind def


%~ # test: rgb2gray
%~ gs -dNOPAUSE -dBATCH -sDEVICE=ps2write -sOutputFile=./blah-slide-hackRGB-gray.ps ./HackRGB.ps ./blah-slide-gsps2w.ps
%~ # gray2cmyk
%~ gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=./blah-slide-hackRGB-gray-ci.pdf ./HackRGB-cmyk-inv.ps ./blah-slide-hackRGB-gray.ps
%~ # check separations - looks OK
%~ gs -sDEVICE=tiffsep -dNOPAUSE -dBATCH -dSAFER -dFirstPage=1 -dLastPage=1 -sOutputFile=p%02d.tif blah-slide-hackRGB-gray-ci.pdf && eog p01.tif 2>/dev/null

关于如何做的一些想法？

问候。

Answer 1

这是一个快速破解的技巧。在 oldsetrgbcolor 之后，您可以检查 cmyk 颜色并修改它。也许今晚我可以制作一个更通用的模块，将其剪切以检查 50% 洋红色并将其更改为 100%。 (cmyk-) print pstack 行将显示找到的 cmyk 颜色，如果计算出的颜色不完全是 .5，您可能需要它，就像它可能是 .49，所以一旦您看到这些值, 删除线。

旧

  }{
    oldsetrgbcolor      %% Set the RGB values
  }ifelse

新

  }{
    oldsetrgbcolor      %% Set the RGB values
    currentcmykcolor    %puts 4 numbers on the stack
    (cmyk-) print pstack %display the colors (remove when things work correctly)
    3 -1 roll           %put magenta on top of stack
    dup                 %make copy of magenta value
    .5                  %put magenta test value on stack (then may not be exactly .5, see pstack)
    eq                  %see of magenta is equal to test value (.5)
    {pop 1}if           %if it is equal, pop off the .5 and put a 1 onto the stack
    3 1 roll            %put magenta back where it belongs in the stack
    setcmykcolor        %reset the cmyk to have new magenta value
  }ifelse