next up previous contents index
Next: PENCIL /WEIGHT Up: PENCIL Previous: PENCIL   Contents   Index


PENCIL /COLOUR

        PENCIL [N] /COLOUR Arg

    Modify the current pen color, or the color of the N-th pen.

    The  argument  can  be  a color name (subset of the X11 colors catalog),
    e.g. RED, LIGHT_SEA_GREEN, MEDIUM_BLUE... The complete list is available
    by typing "PENCIL /COLOUR ?". The colors can also be displayed thanks to
    the demonstration procedure "@ gag_demo:demo-pencolors.greg".  The  list
    is  also  available  in the character array GTV%COLORS for use in proce-
    dures.

    There are 3 special color names:
      BACKGROUND resolves as WHITE on white devices and BLACK on  black  de-
                 vices,
      FOREGROUND  resolves  as BLACK on white devices and WHITE on black de-
                 vices,
      NEGATIVE inverts the pixel colors below the  graphical  segment  begin
                 drawn.  This  ensures  that  the segment is always visible,
                 whatever the context. NEGATIVE is supported only for X  and
                 PNG  devices.  Other  devices use the FOREGROUND color as a
                 fallback.

    The argument can also be an integer value (explicit, or a variable name,
    or  the  result  of  a math expression) from -1 to 23 with the following
    signification:
      -1 NEGATIVE
       0 FOREGROUND
       1 RED
       2 GREEN
       3 BLUE
       4 CYAN
       5 YELLOW
       6 MAGENTA
       7 BACKGROUND
       8 to 23: those 16 colors can be customized by the user (see  HELP LUT
         /PEN  for  details).  They can be used as any other color, but they
         also correspond as the "fill pens" used by the command RGMAP /GREY.
         Those colors are dynamic, i.e., by default, changing them will also
         modify the segments previously drawn with  them  (see  HELP  CHANGE
         LUT).


Gildas manager 2023-06-01