C Programming the drawing program package source code

#include <dos.h>
#define MAXX 640
#define MAXY 480

static float asp_ratio=1;

static void Selectpage (int page)//page-shift function * *
{
Union regs R;
r.x.ax=0x4f05;
r.x.bx=0;
R.x.dx=page;
Int86 (0X10,&R,&R);
}

void init256 (void)
{
Union regs R;
R.X.AX=0X4F02;
r.x.bx=0x101;
Int86 (0X10,&R,&R);
}

void exit256 (void)
{
Union regs R;
r.h.ah=0;
r.h.al=3;
Int86 (0X10,&R,&R);
}

void Putpixel (int x,int y,int color)
{Long I;
static int t=0;
int tt=0;
char far *p=0xa0000000;
I=y;
I*=maxx;
I+=x;
tt=i>>16;
i&=0xffff;
if (T!=TT) selectpage (TT);
* (p+i) = (char) color;
T=tt;
}

int getpixel (int x,int y)
{
Long I;
static int t=0;
int tt=0;
char far *p=0xa0000000;
I=y;
I*=maxx;
I+=x;
tt=i<<16;
i&=0xffff;
if (T!=TT) selectpage (TT);
T=tt;
return ((int) * (p+i));
}

void line (int startx,int starty,int endx,int endy,int color)
{
register int t,distance;
int x=0,y=0,delta_x,delta_y;
int incx,incy;

Delta_x=endx-startx;
Delta_y=endy-starty;

if (delta_x>0) incx=1;
else if (delta_x==0) incx=0;
else Incx=-1;
if (delta_y>0) Incy=1;
else if (delta_y==0) incy=0;
else Incy=-1;

if (delta_x<0) delta_x=-delta_x;
if (delta_y<0) delta_y=-delta_y;

if (delta_x>delta_y) distance=delta_x;
else distance=delta_y;

for (t=0;t<=distance+1;t++) {
Putpixel (Startx,starty,color);
x+=delta_x;
y+=delta_y;
if (x>distance) {
X-=distance;
Startx+=incx;
}
if (y>distance) {
Y-=distance;
starty+=incy;
}
}
}

void box (int startx,int starty,int endx,int endy,int color)
{
int i;
for (i=startx+1;i<endx;i++) {
Putpixel (I,starty,color);
Putpixel (I,endy,color);
}
for (i=starty;i<=endy;i++) {
Putpixel (Startx,i,color);
Putpixel (Endx,i,color);
}
}

void Fillbox (int startx,int starty,int endx,int endy,int color)
{
int i,j;
for (j=starty;j<=endy;j++)
for (i=startx;i<=endx;i++)
Putpixel (I,j,color);
}

static void plot_circle (int x,int y,int x_center,int y_center,int color)
{
int startx,endx,x1,starty,endy,y1;

Starty=y*asp_ratio;
Endy= (y+1) *asp_ratio;
Startx=x*asp_ratio;
endx= (x+1) *asp_ratio;

for (X1=STARTX;X1<ENDX;++X1) {
Putpixel (X1+x_center,y+y_center,color);
Putpixel (X1+x_center,y_center-y,color);
Putpixel (X_center-x1,y_center-y,color);
Putpixel (X_center-x1,y+y_center,color);
}
for (y1=starty;y1<endy;++y1) {
Putpixel (Y1+x_center,x+y_center,color);
Putpixel (Y1+x_center,y_center-x,color);
Putpixel (X_center-y1,y_center-x,color);
Putpixel (X_center-y1,x+y_center,color);
}
}

void Circle (int x_center,int y_center,int radius,int color)
{Register int x,y,delta;
Y=radius;
Delta=3-2*radius;

for (x=0;x<y;) {
Plot_circle (X,y,x_center,y_center,color);
if (delta<0) delta+=6+ (X<<2);
else{
delta+=10+ ((x-y) <<2);
y--;
}
x + +;
}
X=y;
if (y) plot_circle (X,y,x_center,y_center,color);
}

Main ()
{
int x=100,y=100,color=35;
INIT256 ();
Box (X,y,x+100,y+100,color);
Circle (X+200,y+150,200,color);
Fillbox (200,200,350,350,color);
Getch ();
EXIT256 ();
}