gscarc(3g) — AIX PS/2 1.2.1



GSCARC(3g,L)                AIX Technical Reference                GSCARC(3g,L)



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gscarc



PURPOSE

Draws a circular arc between two points.

C SYNTAX

int gscarc_ (cx, cy, cr, bx, by, ex, ey)

int *cx, *cy, *cr, *bx, *by, *ex, *ey;

FORTRAN SYNTAX

INTEGER function gscarc (cx, cy, cr, bx, by, ex, ey)

INTEGER cx, cy, cr, bx, by, ex, ey

PASCAL SYNTAX

FUNCTION gscarc_ (

VAR cx, cy, cr, bx, by, ex, ey : INTEGER
): INTEGER [PUBLIC];

DESCRIPTION

The gscarc subroutine draws a counterclockwise circular arc of the specified
radius from the beginning point to the ending point.  The radius is expressed
in number of pixels.

The relevant attributes are:

  o Color map
  o Plane mask
  o Line color index
  o Line style
  o Logical operation.

Parameters

cx, cy   Define the coordinates of the center of the circle.

         For displays, the center is restricted to -2048 to 2048.

         For printers and plotters, the center is restricted to screen
         coordinates.





Processed November 7, 1990       GSCARC(3g,L)                                 1



GSCARC(3g,L)                AIX Technical Reference                GSCARC(3g,L)



cr       Defines the radius of the circle.

bx, by   Define the coordinates of the beginning point on the circle.

ex, ey   Define the coordinates of the ending point on the circle.

If the beginning and ending points are identical, a full circle is drawn.

Note that the application must control the accuracy of the end points (bx, by
and ex, ey) when drawing circular arcs.  If the start point of the arc and end
point of the arc lie within one pixel of the true circle, the arc will be drawn
successfully.  Other values can cause the subroutine to fail.  If the gscarc
subroutine fails because of an inaccurate starting point, GS_ASTR is returned,
while for an inaccurate ending point, GS_AEND is returned.

RETURN VALUE

GS_SUCC  Successful.
GS_CORD  Invalid coordinate.
GS_RDUS  Invalid radius for circles.
GS_INAC  Virtual terminal inactive.
GS_AEND  Invalid end point.
GS_ASTR  Invalid start point.
































Processed November 7, 1990       GSCARC(3g,L)                                 2

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