graphics.hlp (
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_pie, _pie_wxy
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The _pie functions draw a pie-shaped wedge by drawing an
elliptical arc whose center and two endpoints are joined by lines.
The _pie function uses the view coordinate system. The center of
the arc is the center of the bounding rectangle specified by the
view-coordinate points (<x1>, <y1>) and (<x2>, <y2>). The arc
starts where it intersects the vector defined by (<x3>, <y3>) and
ends where it intersects the vector (<x4>, <y4>).
The _pie_wxy routine (implemented as a macro) uses the window
coordinate system. The center of the arc is the center of the
bounding rectangle specified by the window-coordinate pairs
(<pwxy1>, <pwxy2>). The arc starts where it intersects the vector
defined by <pwxy3> and ends where it intersects the vector defined
by <pwxy4>.
The pie-shaped wedge is drawn in a counterclockwise direction,
using the current color. The <control> parameter can be one of the
following manifest constants: _GBORDER or _GFILLINTERIOR.
The control option given by _GFILLINTERIOR is equivalent to a
subsequent call to the _floodfill function using the center of the
ellipse as the starting point and the current color (set by
_setcolor) as the boundary color.
Return Value
The function returns a nonzero value if the pie is drawn
successfully; otherwise, it returns 0.
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