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PENCIL COLORS

        There are 25 colors available for PENS. Colors -1, 0 and 7 are  SPE-
    CIAL, colors 1 to 6 are FIXED (named colors or their equivalent shade of
    grey on grayscale terminals). The last 16 are user-defined.

    Color 0 (the default for the default PEN 0)  is  ALWAYS  the  foreground
    color (i.e., always visible whatever the background color of the graphic
    window is), and becomes BLACK on the paper hardcopy. Color 7  is  ALWAYS
    the background color, useful for text written on an grey-scale image for
    example.

    Colors 1 to 6 are defined as follows for a standard display with  suffi-
    cient colors available in its colormap:
        "red","green","blue","cyan","yellow" and "magenta"
    For grey-scale displays, it becomes:
        "grey42","grey70","grey14","grey28","grey56" and "grey84"
    This  may  vary depending on the number of available colors on your dis-
    play.

    The last 16 colors are user-definable (see HELP LUT) and  correspond  to
    the  16  'FILL PENS'  used  as  fill  colors  in  various commands, like
    RGMAP /GREY or POLYGON /FILL.

    Finally, the color -1 is negative, which means it will have  an  inverse
    color  of what is behind. It is useful to draw segments which are always
    visible, whatever the context. This special color is available only  un-
    der X and PNG devices. For the others, the foreground color (0) is used.


Gildas manager 2011-09-07