### Key placement

To understand positioning, the best concept is to think of a region, i.e., inside/outside, or one of the margins. Along with the region, keywords left/center/right (l/c/r) and top/center/bottom (t/c/b) control where within the particular region the key should be placed.

When in inside mode, the keywords left (l), right (r), top (t), bottom (b), and center (c) push the key out toward the plot boundary as illustrated:

        t/l   t/c   t/r

        c/l    c    c/r

        b/l   b/c   b/r

When in outside mode, automatic placement is similar to the above illustration, but with respect to the view, rather than the graph boundary. That is, a border is moved inward to make room for the key outside of the plotting area, although this may interfere with other labels and may cause an error on some devices. The particular plot border that is moved depends upon the position described above and the stacking direction. For options centered in one of the dimensions, there is no ambiguity about which border to move. For the corners, when the stack direction is vertical, the left or right border is moved inward appropriately. When the stack direction is horizontal, the top or bottom border is moved inward appropriately.

The margin syntax allows automatic placement of key regardless of stack direction. When one of the margins lmargin (lm), rmargin (rm), tmargin (tm), and bmargin (bm) is combined with a single, non-conflicting direction keyword, the following illustrated positions may contain the key:

             l/tm  c/tm  r/tm

        t/lm                  t/rm

        c/lm                  c/rm

        b/lm                  b/rm

             l/bm  c/bm  r/bm

Keywords above and over are synonymous with tmargin. For version compatibility, above or over without an additional l/c/r or stack direction keyword uses center and horizontal. Keywords below and under are synonymous with bmargin. For compatibility, below or under without an additional l/c/r or stack direction keyword uses center and horizontal. A further compatibility issue is that outside appearing without an additional t/b/c or stack direction keyword uses top, right and vertical (i.e., the same as t/rm above).

The position can be a simple x,y,z as in previous versions, but these can be preceded by one of five keywords (first, second, graph, screen, character) which selects the coordinate system in which the position of the first sample line is specified. See coordinates (p. ) for more details. The effect of left, right, top, bottom, and center when position is given is to align the key as though it were text positioned using the label command, i.e., left means left align with key to the right of position, etc.