1gl_bcircle(3)                 Svgalib User Manual                gl_bcircle(3)
2
3
4

NAME

6       gl_bcircle - draw a filled or unfilled Bresenham circle
7
8

SYNOPSIS

10       #include <vgagl.h>
11
12       void gl_bcircle(int x, int y, int r, int c, int fill);
13
14

DESCRIPTION

16       Draw  a  Bresenham circle of radius r in color c , centered at ( x ,  y
17       ).
18
19       Fill should be 0 for a hollow circle, or any other value  for  a  solid
20       color.
21
22       This  function differs from gl_circle (3) and gl_fillcircle (3) in that
23       it looks good in 320 x 200 screen modes.  The  modified  algorithm  was
24       provided  by Chris Atenasio <chris@svgalib.org>, and is based upon Bre‐
25       senham's formula.
26
27       Note that the "circle" is technically an ellipse, and is actually wider
28       than  it  is tall. Therefore, r is equal to the circle's height, but is
29       less than its width. This distortion is necessary to accomodate the 8:5
30       aspect ratio (e.g., 320 x 200).
31
32       I  don't  recommend  using  this  function in standard 4:3 screen modes
33       (e.g., 640 x 480 and higher). Furthermore, care must be taken so that a
34       circle drawn with this function isn't copied to a screen with a differ‐
35       ent aspect ratio. Otherwise, the result may be undesirable.
36
37

SEE ALSO

39       svgalib(7),   vgagl(7),   svgalib.conf(5),   threedkit(7),   testgl(1),
40       plane(1),   wrapdemo(1),   gl_circle(3),  gl_clearscreen(3),  gl_color‐
41       font(3),  gl_disableclipping(3),  gl_enableclipping(3),  gl_fillbox(3),
42       gl_fillcircle(3),   gl_hline(3),  gl_line(3),  gl_setclippingwindow(3),
43       gl_setpalette(3),    gl_setpalettecolor(3),     gl_setpalettecolors(3),
44       gl_setpixel(3),  gl_setpixelrgb(3),  gl_setrgbpalette(3),  gl_setwrite‐
45       mode(3).
46
47

AUTHOR

49       This manual page was written by Jay Link <jlink@svgalib.org>.
50
51
52
53Svgalib (>= 1.4.1)                4 Dec 1999                     gl_bcircle(3)