/* avivA Starkman
 * May 30, 1996
 * "Electro-Sketch": An Electronic Etch-A-Sketch
 * written for PowerC compiler */


#include <graphics.h>
#include <bios.h>

#define STEP 2				/* line increment amount */
#define MAXX 319			/* screen size for CGA_320 */
#define MAXY 199
#define BGCOLOR 1			/* background color: blue */
#define PALETTE 1			/* palette: cyan/magenta/white */
#define TITLECOLOR 1			/* title color: cyan */
#define BOXCOLOR 2			/* box color: magenta */
#define LINECOLOR 3			/* line color: white */

void ShakeScreen(int *x, int *y, int lines);

main() {

int locx, locy;				/* current screen position */
int oldcol = 0;				/* save color of old location */
char ch;
int lines = 1;				/* line drawing = ON */

if (setvmode(CGA_320) != CGA_320) {
    printf ("ERROR: This program requires CGA, EGA, or VGA card\n");
    exit(1);
}
else {
    setcolor(BGCOLOR, PALETTE);
    ShakeScreen(&locx, &locy, lines);

ch = getch();

while ((ch != 'q') && (ch != 'Q'))
{
    switch (ch)
    {
	/* clear screen */
	case 'c':
	case 'C': clrscrn2(0xf0);
		  ShakeScreen(&locx, &locy, lines);
		  break;

	/* toggle line drawing */
	case 't':
	case 'T': pen_color(TITLECOLOR);
		  if (lines) {
		      lines = 0;
		      move_to(292, 179);
		      plots("OFF");
		  } else {
		      lines = 1;
		      move_to(292, 179);
		      plots("ON ");
		  }
		  pen_color(LINECOLOR);
		  move_to(locx, locy);
		  break;

	/* move up */
	case 'k':
	case 'K': if (locy >= STEP) {
		      if (!lines) {		/* restore old pixel */
			  pen_color(oldcol);
			  setpixel(locx, locy);
			  pen_color(LINECOLOR);
		      }
		      locy -= STEP;
		      if (lines)
			  line_to(locx, locy);
		      else {
			  move_to(locx, locy);
			  oldcol = getpixel(locx, locy); /* save old pixel */
		      }
		  }
		  break;

	/* move down */
	case 'j':
	case 'J': if (locy <= MAXY - STEP) {
		      if (!lines) {
			  pen_color(oldcol);
			  setpixel(locx, locy);
			  pen_color(LINECOLOR);
		      }
		      locy += STEP;
		      if (lines)
			  line_to(locx, locy);
		      else {
			  move_to(locx, locy);
			  oldcol = getpixel(locx, locy);
		      }
		  }
		  break;

	/* move left */
	case 'h':
	case 'H': if (locx >= STEP) {
		      if (!lines) {
			  pen_color(oldcol);
			  setpixel(locx, locy);
			  pen_color(LINECOLOR);
		      }
		      locx -= STEP;
		      if (lines)
			  line_to(locx, locy);
		      else {
			  move_to(locx, locy);
			  oldcol = getpixel(locx, locy);
		      }
		  }
		  break;

	/* move right */
	case 'l':
	case 'L': if (locx <= MAXX - STEP) {
		      if (!lines) {
			  pen_color(oldcol);
			  setpixel(locx, locy);
			  pen_color(LINECOLOR);
		      }
		      locx += STEP;
		      if (lines)
			  line_to(locx, locy);
		      else {
			  move_to(locx, locy);
			  oldcol = getpixel(locx, locy);
		      }
		  }
    } /* end switch */

    /* show current position in title color */
	pen_color(TITLECOLOR);
	setpixel(locx, locy);
	pen_color(LINECOLOR);

    ch = getch();
    } /* end while */

    setvmode(DEFAULTMODE);
    exit(0);
    } /* end else */
} /* end main */

void ShakeScreen(int *x, int *y, int lines) {
/* ShakeScreen re-initializes the screen for a new drawing */

    pen_color(TITLECOLOR);		/* print title */
    move_to(100, 0);
    plots("Electro-Sketch");

    move_to (8, 116);			/* print instruction box */
    plots("Left:");
    move_to(8, (116 + 1*11));
    plots("Right:");
    move_to(8, (116 + 2*11));
    plots("Up:");
    move_to(8, (116 + 3*11));
    plots("Down:");
    move_to(8, (116 + 4*11));
    plots("Toggle:");
    move_to(8, (116 + 5*11));
    plots("Clear:");
    move_to(8, (116 + 6*11));
    plots("Quit:");

    pen_color(BOXCOLOR);
    move_to(0, 108);
    box(87, 89, 0);
    move_to(72, 116);
    plotch('H');
    move_to(72, (116 + 1*11));
    plotch('L');
    move_to(72, (116 + 2*11));
    plotch('K');
    move_to(72, (116 + 3*11));
    plotch('J');
    move_to(72, (116 + 4*11));
    plotch('T');
    move_to(72, (116 + 5*11));
    plotch('C');
    move_to(72, (116 + 6*11));
    plotch('Q');

    move_to(132, 190);			/* print our names */
    plots("By: Doug, Chris & Aviva");

    move_to(236, 179);			/* print line status */
    plots("Lines:");

    pen_color(TITLECOLOR);
    move_to(292, 179);
    if (lines)
	plots("ON ");
    else
	plots("OFF");

    move_to(160, 100);			/* go to center of screen */
    *x = 160;				/* initialize loc variables */
    *y = 100;
    setpixel(*x, *y);			/* show current position */
    pen_color(LINECOLOR);
}