STRUCTURE: UF_DISP_grid_s

DESCRIPTION: This is the definition of a grid structure. It is used to
specifies the parameters to apply when a grid is used.
There are 3 grid application contexts & 2 grid types. The
grid behaviors and appearances are different among them.
Grid "emphasis" lines and circles are drawn as solid lines,
while other grid line and circles are drawn as a series of
dots.

show_grid - TRUE to make the grid visible, FALSE otherwise.
snap_to_grid - TRUE to enable snapping, FALSE otherwise.
grid_color - 1 to 216
grid_type - Either rectangular (default) or polar
grid_non_uniform - TRUE allows X & Y units to be different,
FALSE (default) is otherwise.
grid_on_top - TRUE to show grid on top of all displayed graphics


rectangular_grid_emphasis - TRUE (default) to draw the emphasis lines,
FALSE otherwise.
grid_unit_x - Distance between dots along X in inches/mm.
grid_unit_y - Distance between dots along Y. If 'grid_non_uniform' is
FALSE, this field is ignored.
grid_line_every_x - No. of dots between each grid line along X.
grid_line_every_y - No. of dots between each grid line along Y. If
'grid_non_uniform' is FALSE, this field is ignored.
grid_emphasis_every_x - This value must be a multiple of
'grid_line_every_x'.
grid_emphasis_every_y - Like 'grid_emphasis_every_x' except it is ignored
when 'grid_non_uniform' is FALSE.


polar_grid_emphasis - TRUE (default) to draw the emphasis lines,
FALSE otherwise.
grid_angular_unit - Angular distance between dots in degrees (at the
first ring when all dots are visible).
grid_angular_line_every - No. of fully visible dots between each grid line.
grid_angular_emphasis_every - This value must be a multiple of
'grid_angular_line_every'.
grid_radial_unit - Distance between dots along angular lines in inche/mm.
grid_radial_circle_every - No. of dots between each concentric circles.
grid_radial_emphasis_every - this value must be a multiple of
'grid_radial_circle_every'.