The _rectangle functions draw a rectangle with the current line style.
The _rectangle function uses the view coordinate system. The view
coordinate points (x1, y1) and (x2, y2) are the diagonally opposed corners
of the rectangle.
The _rectangle_w function uses the window coordinate system. The window
coordinate points (wx1, wy1) and (wx2, wy2) are the diagonally opposed
corners of the rectangle.
The _rectangle_wxy function uses the window coordinate system. The window
coordinate points (pwxy1 and (pwxy2) are the diagonally opposed corners of
the rectangle.
The _rectangle_w and _rectangle_wxy routines are implemented as macros.
The control parameter can be one of the following manifest constants:
_GFILLINTERIOR, or _GBORDER.
If the current fill mask is NULL, no mask is used. Instead, the rectangle
is filled with the current color.
----- Note -----
If you try to fill the rectangle with the _floodfill function, the
rectangle must be bordered by a solid line-style pattern.
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Return Value
The function returns a nonzero value if the rectangle is drawn
successfully, 0 if not.