code: public void setCMYKColorFill(int cyan, int magenta, int yellow, int black) {
          content.append((float)(cyan & 0xFF) / 0xFF);
          content.append(' ');
          content.append((float)(magenta & 0xFF) / 0xFF);
          content.append(' ');
          content.append((float)(yellow & 0xFF) / 0xFF);
          content.append(' ');
          content.append((float)(black & 0xFF) / 0xFF);
          content.append(" k").append_i(separator);
      }
docs: Changes the current color for filling paths (device dependent colors!).
  <P>
  Sets the color space to <B>DeviceCMYK</B> (or the <B>DefaultCMYK</B> color space),
  and sets the color to use for filling paths.</P>
  <P>
  This method is described in the 'Portable Document Format Reference Manual version 1.3'
  section 8.5.2.1 (page 331).</P>
  <P>
  Following the PDF manual, each operand must be a number between 0 (no ink) and
  1 (maximum ink). This method however accepts only integers between 0x00 and 0xFF.</P>
  
  @param cyan the intensity of cyan
  @param magenta the intensity of magenta
  @param yellow the intensity of yellow
  @param black the intensity of black