circle.c

smallbasic for linux

/* 
*/

#include "device.h"
#include "osd.h"
#if !defined(_PalmOS)
#include <math.h>
#else
#define	M_PI	3.14159265358979323846
#endif

void	Set4Pixels(int x,int y,int xc,int yc)	SEC(BIO);
void	Set4Line(int x,int y,int xc,int yc)		SEC(BIO);
void	simple_ellipse(int xc, int yc, int rx, int ry, int fill) SEC(BIO);

void	Set4Pixels(int x,int y,int xc,int yc)
{
	osd_setpixel(xc+x, yc+y);
	osd_setpixel(xc-x, yc+y);
	osd_setpixel(xc+x, yc-y);
	osd_setpixel(xc-x, yc-y);
}

void	Set4Line(int x,int y,int xc,int yc)
{
	osd_line(xc-x, yc+y, xc+x, yc+y);
	osd_line(xc-x, yc-y, xc+x, yc-y);
}

/*
*/
void	simple_ellipse(int xc, int yc, int rx, int ry, int fill)
{
	int		x = 0;
	int		y = ry;

	long    a = rx;                         /* use 32-bit precision */
	long    b = ry;

	long    Asquared = a * a;               /* initialize values outside */
	long    TwoAsquared = 2 * Asquared;     /*  of loops */
	long    Bsquared = b * b;
	long    TwoBsquared = 2 * Bsquared;

	long    d;
	long    dx,dy;

	d = Bsquared - Asquared*b + Asquared/4L;
	dx = 0;
	dy = TwoAsquared * b;

	while ( dx < dy )  {
		if	( fill )
			Set4Line(x, y, xc, yc);
		else
			Set4Pixels(x, y, xc, yc);


		if ( d > 0L ) {
			-- y;
			dy -= TwoAsquared;
			d -= dy;
			}

		++ x;
		dx += TwoBsquared;
		d += Bsquared + dx;
        }

	d += (3L*(Asquared-Bsquared)/2L - (dx+dy)) / 2L;

	while ( y >= 0 )	{

		if	( fill )
			Set4Line(x, y, xc, yc);
		else
			Set4Pixels(x, y, xc, yc);

		if ( d < 0L )	{
			++ x;
			dx += TwoBsquared;
			d += dx;
			}

		-- y;
		dy -= TwoAsquared;
		d += Asquared - dy;
        }
}

/*
*/
void	dev_ellipse(int xc, int yc, int xr, int yr, double aspect, int fill)
{
	if ( os_graphics == 0 )	
		return;

	simple_ellipse(xc, yc, xr, yr * aspect, fill);
}

/*
*/
void	dev_arc(int xc, int yc, double r, double start, double end, double aspect)
{
	double	th, ph, xs, ys, xe, ye, x, y;
	int		i;

	if ( os_graphics == 0 )	
		return;

	if	( r < 1 )
		r = 1;

	while ( end < start )	end += M_PI * 2.0;
	th = (end - start) / r;
	xs = xc + r * cos(start);
	ys = yc + r * aspect * sin(start);
	xe = xc + r * cos(end);
	ye = yc + r * aspect * sin(end);
	x = xs; y = ys;
	for ( i = 1; i < r; i ++ )	{
		ph = start + i * th;
		xs = xc + r * cos(ph);
		ys = yc + r * aspect * sin(ph);
		osd_line(x, y, xs, ys);
		x = xs; y = ys;
		}
	osd_line(x, y, xe, ye);
}