Grid(3)
displays a grid in a viewer and constrains points to lie on it
SYNOPSIS
#include <Unidraw/grid.h>
DESCRIPTION
The Grid object performs two functions: it displays a grid in a viewer,
and it can constrain points to lie on the grid. The base class draws
the grid as a simple array of dots; subclasses can draw arbitrarily
complex grids.
PUBLIC OPERATIONS
- Grid(float w, float h, float xincr, float yincr)
-
The constructor parameters correspond to a width, a height, and
independent units of graduation for the horizontal and vertical axes,
all in pixels. The Grid base class employs a special-purpose graphic
to render itself, one that draws an array of dots based on the
information supplied in this constructor.
- virtual Graphic* GetGraphic()
-
Return the graphic used to render the grid.
- virtual void Constrain(Coord&, Coord&)
-
Constrain the given coordinate pair to fall on the grid. The pair is
changed to fall on the nearest grid point by default.
- virtual void Visiblity(boolean)
-
Make the grid visible (specify true) or invisible (specify false).
- virtual boolean IsVisible()
-
Return whether the grid is visible or not.
- virtual void SetSpacing(float xincr, float yincr)
-
Reset the grid's units of graduation.
PROTECTED OPERATIONS
- Grid(Graphic*)
-
The protected constructor allows subclasses to specify an arbitrary
graphic for rendering the grid. Subclasses that use this constructor
must also redefine the Constrain operation.