NAME¶
gl_bcircle - draw a filled or unfilled Bresenham circle
SYNOPSIS¶
#include <vgagl.h>
void gl_bcircle(int x, int y, int
r, int c, int fill);
DESCRIPTION¶
Draw a Bresenham circle of radius
r in color
c , centered at
(
x , y ).
Fill should be 0 for a hollow circle, or any other value for a solid
color.
This function differs from gl_circle (3) and gl_fillcircle (3) in that it looks
good in 320 x 200 screen modes. The modified algorithm was provided by Chris
Atenasio <chris@svgalib.org>, and is based upon Bresenham's formula.
Note that the "circle" is technically an ellipse, and is actually
wider than it is tall. Therefore,
r is equal to the circle's height,
but is less than its width. This distortion is necessary to accomodate the 8:5
aspect ratio (e.g., 320 x 200).
I don't recommend using this function in standard 4:3 screen modes (e.g., 640 x
480 and higher). Furthermore, care must be taken so that a circle drawn with
this function isn't copied to a screen with a different aspect ratio.
Otherwise, the result may be undesirable.
SEE ALSO¶
svgalib(7),
vgagl(7),
svgalib.conf(5),
threedkit(7),
testgl(1),
plane(1),
wrapdemo(1),
gl_circle(3),
gl_clearscreen(3),
gl_colorfont(3),
gl_disableclipping(3),
gl_enableclipping(3),
gl_fillbox(3),
gl_fillcircle(3),
gl_hline(3),
gl_line(3),
gl_setclippingwindow(3),
gl_setpalette(3),
gl_setpalettecolor(3),
gl_setpalettecolors(3),
gl_setpixel(3),
gl_setpixelrgb(3),
gl_setrgbpalette(3),
gl_setwritemode(3).
AUTHOR¶
This manual page was written by Jay Link <jlink@svgalib.org>.
