/*	BAR.C

	Sample program for interfacing Turbo C with Turbo Prolog

	Copyright (c) Borland International 1987
	All Rights Reserved.
*/

#include <dos.h>

/* new prototype for _int86 */

int _int86(int intr_num, union REGS *inregs, union REGS *outregs);


videodot(int x, int y, int color)
{
	union REGS inr,outr;

	inr.h.ah = 12;		   /* write pixel */
	inr.h.al = color;
	inr.x.cx = x;
	inr.x.dx = y;
	_int86(16,&inr,&outr); /* call video intr */
}

/* Draws a line on the screen from (x1, y1) to (x2, y2) in a selected color */
line(int x1, int y1, int x2, int y2, int color)
{
	int xdelta;  /* The change in x coordinates */
	int ydelta;  /* The change in y coordinates */
	int xstep;   /* The change to make in the x coordinate in each step */
	int ystep;   /* The change to make in the y coordinate in each step */
	int change;  /* The amount that the x or y coordinate has changed */

	xdelta = x2 - x1;		/* Calculate the change in x coordinates */
	ydelta = y2 - y1;		/* Calculate the change in y coordinates */
	if (xdelta < 0)
	{						/* The line will be drawn from right to left */
		xdelta = -xdelta;
		xstep = -1;
	}
	else					/* The line will be drawn from left to right */
		xstep = 1;
	if (ydelta < 0)
	{						/* The line will be drawn from bottom to top */
		ydelta = -ydelta;
		ystep = -1;
	}
	else					/* The line will be drawn from top to bottom */
		ystep = 1;
	if (xdelta > ydelta)	/* x changes quicker than y */
	{
		change = xdelta >> 1;  /* change set to twice the value of xdelta */
		while (x1 != x2)	   /* Draw until the terminating dot is reached */
		{

			videodot(x1, y1, color);	/* Draw a dot on the screen */
			x1 += xstep;				/* Update x coordinate */
			change += ydelta;			/* Update change */
			if (change > xdelta)
										/* If change is large enough to
											update the y coordinate */
			{
				y1 += ystep;	   /* Update the y coordinate */
				change -= xdelta;  /* Reset change */
			}
		}
	}
	else					   /* y changes quicker than x */
	{
		change = ydelta >> 1;  /* change set to twice the value of ydelta */
		while (y1 != y2)	   /* Draw until the terminating dot is reached */
		{
			videodot(x1, y1, color);	/* Draw a dot on the screen */
			y1 += ystep;				/* Update y coordinate */
			change += xdelta;			/* Update change */
			if (change > ydelta)
					/* If change is large enough to update the x coordinate */
			{
				x1 += xstep;		/* Update the x coordinate */
				change -= ydelta;	/* Reset change */
			}
		}
	}
} /* line */

bar_0(int x1, int y1, int width, int height, int color)
{
	int count;  /* Counter variable used in filling bar */
	int x2, y2, x3, y3, x4, y4;  /* Additional points on the bar */
	int wfactor;	/* The number of pixels to shift the bar to the right */
	int hfactor;	/* The number of pixels to shift the bar up */
/*

The x and y values are as follows:

   x1 x2   x3  x4
	|  |	|  |
	|  v	|  v
y2--|>/ÚÄÄÄÄ|ÄÄ¿
	v/ ³	v /³
y1->ÉÍÍÍÍÍÍÍ»/ ³
	º  ³	º  ³
	º  ³	º  ³
	º  ³	º  ³
	º  ³	º  ³
	º  ³	º  ³
y3---->ÀÄÄÄĺÄÄÙ
	º /		º /
y4->ÈÍÍÍÍÍÍͼ/

*/

	wfactor = width / 5;	   /* figure out wfactor and hfactor */
	hfactor = height / 12;
	x2 = x1 + wfactor;	   /* compute the location of the points on the bar */
	x3 = x1 + width;
	x4 = x3 + wfactor;
	y2 = y1 - hfactor;
	y3 = y1 + height - hfactor;
	y4 = y1 + height;
	line(x1, y1, x3, y1, 2);	/* draw front of the bar */
	line(x3, y1, x3, y4, 2);
	line(x3, y4, x1, y4, 2);
	line(x1, y4, x1, y1, 2);
	line(x3, y1, x4, y2, 2);	/* draw side of the bar */
	line(x4, y2, x4, y3, 2);
	line(x4, y3, x3, y4, 2);
	line(x1, y1, x2, y2, 2);	/* draw top of the bar */
	line(x2, y2, x4, y2, 2);
	line(x1, y4, x2, y3, 3);
	line(x2, y3, x4, y3, 3);	/* draw back of the bar */
	line(x2, y3, x2, y2, 3);
	for (count = y1 + 1; count < y4; count++)	  /* fill in the bar */
		line(x1 + 1, count, x3, count, color);
} /* bar_0 */