trusty (3) gl_bcircle.3.gz

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>.