PLOT(5-BSD)         RISC/os Reference Manual          PLOT(5-BSD)



NAME
     plot - graphics interface

DESCRIPTION
     Files of this format are produced by routines described in
     plot(3X) and plot(3F), and are interpreted for various dev-
     ices by commands described in plot(1G).  A graphics file is
     a stream of plotting instructions.  Each instruction con-
     sists of an ASCII letter usually followed by bytes of binary
     information.  The instructions are executed in order.  A
     point is designated by four bytes representing the x and y
     values; each value is a signed integer.  The last designated
     point in an l, m, n, a, or p instruction becomes the
     `current point' for the next instruction.  The a and c
     instructions change the current point in a manner dependent
     upon the specific device.

     Each of the following descriptions begins with the name of
     the corresponding routine in plot(3X).

     m  move: The next four bytes give a new current point.

     n  cont: Draw a line from the current point to the point
        given by the next four bytes.

     p  point: Plot the point given by the next four bytes.

     l  line: Draw a line from the point given by the next four
        bytes to the point given by the following four bytes.

     t  label: Place the following ASCII string so that its first
        character falls on the current point.  The string is ter-
        minated by a newline.

     a  arc:  The first four bytes give the center, the next four
        give the starting point, and the last four give the end
        point of a circular arc.  The least significant coordi-
        nate of the end point is used only to determine the qua-
        drant.  The arc is drawn counter-clockwise.

     c  circle:  The first four bytes give the center of the cir-
        cle, the next two the radius.

     e  erase: Start another frame of output.

     f  linemod: Take the following string, up to a newline, as
        the style for drawing further lines.  The styles are
        `dotted,' `solid,' `longdashed,' `shortdashed,' and `dot-
        dashed.'  Effective only in plot 4014 and plot ver.

     s  space: The next four bytes give the lower left corner of
        the plotting area; the following four give the upper



                        Printed 11/19/92                   Page 1

PLOT(5-BSD)         RISC/os Reference Manual          PLOT(5-BSD)



        right corner.  The plot will be magnified or reduced to
        fit the device as closely as possible.

        Space settings that exactly fill the plotting area with
        unity scaling appear below for devices supported by the
        filters of plot(1G).  The upper limit is just outside the
        plotting area.  In every case the plotting area is taken
        to be square; points outside may be displayable on dev-
        ices whose face isn't square.

        4013      space(0, 0, 780, 780);
        4014      space(0, 0, 3120, 3120);
        ver       space(0, 0, 2048, 2048);
        300, 300s space(0, 0, 4096, 4096);
        450       space(0, 0, 4096, 4096);

SEE ALSO
     plot(1G), plot(3X), plot(3F), graph(1G)

BUGS
     A label instruction immediately followed by a cont instruc-
     tion does the wrong thing on a 4014.

































 Page 2                 Printed 11/19/92