Draw elliptical arcs.
#include <graph.h>
short __far _arc( short x1, short y1, short x2, short y2, shortx3, short y3,
short x4, short y4);
short __far _arc_w( doublex1, doubley1, doublex2, doubley2, doublex3, doubley3, doublex4, doubley4 );
short __far _arc_wxy( struct _wxycoord __far *pwxy1,
struct _wxycoord __far *pwxy2, struct _wxycoord __far *pwxy3,
struct _wxycoord __far *pwxy4 );
| x1, y1 | Upper-left corner of bounding rectangle | |
| x2, y2 | Lower-right corner of bounding rectangle | |
| x3, y3 | Second point of start vector (center of bounding rectangle is first point) | |
| x4, y4 | Second point of end vector (center of bounding rectangle is first point) | |
| pwxy1 | Upper-left corner of bounding rectangle | |
| pwxy2 | Lower-right corner of bounding rectangle | |
| pwxy3 | Second point of start vector (center of bounding rectangle is first point) | |
| pwxy4 | Second point of end vector (center of bounding rectangle is first point) |
The _arc functions draw elliptical arcs. The center of the arc is the center of the bounding rectangle, which is defined by points (x1,y1) and (x2,y2) for _arc and _arc_w and by points pwxy1 and pwxy2 for _arc_wxy. The arc starts where it intersects an imaginary line extending from the center of the arc through (x3,y3) for _arc and _arc_w and through pwxy3 for _arc_wxy. It is drawn counterclockwise about the center of the arc, ending where it intersects an imaginary line extending from the center of the arc through (x4,y4) for _arc and _arc_w and through pwxy4 for _arc_wxy.
The _arc routine uses the view coordinate system. The _arc_w and _arc_wxy functions use the real-valued window coordinate system.
In each case, the arc is drawn using the current color. Since an arc does not define a closed area, it is not filled.
These functions return a nonzero value if the arc is successfully drawn; otherwise, they return 0.
Standards:None
16-Bit:DOS
32-Bit:None
_ellipse functions, _lineto functions, _pie functions, _rectangle functions, _setcolor
/* ARC.C: This program draws a simple arc. */
#include <graph.h>
#include <stdlib.h>
#include <conio.h>
void main( void )
{
short x, y;
struct _xycoord xystart, xyend, xyfill;
/* Find a valid graphics mode */
if( !_setvideomode( _MAXRESMODE ) )
exit( 1 );
/* Draw arcs */
x = 100; y = 100;
_arc( x - 60, y - 60, x, y, x - 30, y - 60, x - 60, y - 30 );
_arc( x + 60, y + 60, x, y, x, y + 30, x + 30, y );
/* Get endpoints of second arc and enclose the figure, then fill it. */
_getarcinfo( &xystart, &xyend, &xyfill );
_moveto( xystart.xcoord, xystart.ycoord );
_lineto( xyend.xcoord, xyend.ycoord );
_floodfill( xyfill.xcoord, xyfill.ycoord, _getcolor() );
_getch();
_setvideomode( _DEFAULTMODE );
}