Return to circle.3l CVS log

Up to [Research Unix] / researchv10dc / 630 / man / src / p_man / man3

researchv10 Dan Cross

.TH CIRCLE 3L "630 MTG"
.XE "circle()"
.XE "disc()"
.XE "discture()"
.XE "arc()"
.SH NAME
circle, disc, discture, arc \- circle routines
.SH SYNOPSIS
.B #include <dmd.h>
.sp
\f3void circle (b, p, r, f)\f1
.sp
.B void disc (b, p, r, f)
.sp
\f3void discture (b, p, r, t, f)\f1
.sp
\f3void arc (b, p, p1, p2, f)\f1
.sp
.B Bitmap \(**b;
.br
.B Point p, p1, p2;
.br
.B int r;
.br
.B Texture16 \(**t;
.br
.B Code f;
.SH DESCRIPTION
The
.I circle
function
draws the best approximate circle of radius
.I r
centered at Point
.I p
in the Bitmap
.I b
with Code
.IR f .
The circle is guaranteed to be symmetrical about the horizontal,
vertical, and diagonal axes.
.PP
The
.I disc
function
draws a disc of radius
.I r
centered at Point
.I p
in the Bitmap
.I b
with Code
.IR f .
A disc is a circle which has been completely filled.
.PP
The
.I discture
function
draws a disc of radius
.I r
centered at Point
.I p
in the Bitmap
.I b
using the Texture16
.I t
with Code
.IR f .
The
.I discture
function
is similar to
the
.I disc
function
except it allows one to specify a pattern to fill the disc.
.PP
The
.I arc
function
draws a circular arc centered on
.IR p ,
traveling counter-clockwise from
.I p1
to the point on the circle closest to
.IR p2 .
.SH EXAMPLE
The following routine draws a ``smiling face'' in the display Bitmap
with center specified by clicking button 1.
.PP
.RS 3
.ft CM
.nf
.S -4
#include <dmd.h>


main()
{
	int radius;
	extern Texture16 T_darkgrey;
	Point s;
	
 	request(MOUSE);
	wait(MOUSE);
	bttns(1);

	s = mouse.xy;
	radius = 50;

	/* smiling will draw the face.  The nose will be 
	 * placed wherever the mouse is clicked in
	 * the window.
	 */
	
	smiling(&display, s, radius, &T_darkgrey, F_XOR); 

	request(KBD);
	wait(KBD);
}


smiling(b, c, rad, t, f)
Bitmap  *b;
Point    c;
int      rad;
Texture16 *t;
Code     f;
{
    int mino, e; /* offsets for placing */
	         /* eyes, nose and mouth */
    int enrad;   /* radius of eyes and nose */

    mino = rad/2;
    e = rad/3;
    enrad = e/3;
    circle (b, c, rad, f); /* face outline */
    disc (b, Pt(c.x-e, c.y-mino),
         enrad, f);        /* left eye */
    disc (b, Pt(c.x+e, c.y-mino),
         enrad, f);        /* right eye */
    discture (b, c, enrad, t, f); /* nose */
    arc (b, c, Pt(c.x-mino, c.y+mino),
	Pt(c.x+mino, c.y+mino),f);
     /* mouth */
}
.fi
.ft R
.RE
.S +4
.SH SEE ALSO
ellipse(3L), jcircle(3L), jellipse(3L), texture(3R).

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.