Graphics in MS-DOS Environment

LEE HUN HEE

1.Real Coordinate and Windows Coordinate

●Real Coordinate ->(x,y)

●Windows Coordinate ->(wx,wy)

∴

∴

(x,y)->(wx,wy) •

(wx min,wy min)

(x min,y max)

(wx min, wy max)

(x min,y min)

(wx max,wy max)

(x max,ymin)

(wx max,wy min)

(x max,y max)

y

x

minmax

min

minmax

min

wxwx

wxwx

xx

xx

max

minmax

minmaxmin))((wx

xx

wxwxxxwx

minmax

minminmax

minmax

min))((

wywy

wywywywy

yy

yy

minminmax

minmax

minmaxmin )())((

wywywyyy

wywyyywy

(Graphic driver of graphic card must exist in folder)

2.Graphic card and Graphic mode

graphic card Graphic driver

HGA herc.bgi

EGA ega.bgi

VGA egavga.bgi

circle():circle draws a circlerectangle():draws a rectangle (graphics mode)line():line draws a line between two specified pointslineral():line draws a line between two specified pointssetlinestyle():sets the current line style and width or patternfloodfill():flood-fills a bounded regionsetfillstyle():sets the fill pattern and colorgetpixel(): getpixel gets the color of a specified pixelputpixel():putpixel plots a pixel at a specified point

settextstyle():sets the current text characteristicsouttextxy():outtextxy displays a string at the specified location (graphics mode)textheight, ():textheight returns the height of a string in pixelstextwidth():textwidth returns the width of a string in pixels

3.Keyword

getx():

getx returns the current position's x coordinate

gety():

gety returns the current position's y coordinate

getmaxx ():

returns maximum x screen coordinate

getmaxy():

returns maximum y screen coordinate

Initgraph():

initializes the graphics system

closegraph():

shuts down the graphics system

cleardevice:

clears the graphics screen

#include <graph.h>

void main()

{

int driver,mode;

driver=DETECT;

initgraph(&driver,&mode," ");

.

.

graphic

.

.

closegraph();

}

4.program source

#include <graph.h>

void main()

{

int x;

double y;

int driver,mode;

driver=DETECT;

initgraph(&driver,&mode," ");

line(260,0,260,450);

line(0,30,550,30);

line(390,190,420,190);

outtextxy(10,40,"x");

outtextxy(270,400,"y");

outtextxy(270,20,"0");

outtextxy(420,190,"Y=-x*x");

for(x=60;x<460;x++)}

y=0.01*(x-260)*(x-260)+30;

rectangle(x,y,x+2,y+2);

}

getch();

closegraph();

}

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

#include<conio.h>

#include<graphics.h>

#include<math.h>

#define c 32767

int ix,iy,select,select1;

int vx1,vy1,vx2,vy2;

double wx1,wy1,wx2,wy2,txi,tyi,ticx,ticy;

char H[10],V[10],f1[10],f2[10],f3[10],f4[10];

void plot(double, double, int);

void draw(double, double, double, double);

void drawxy(double, double);

void outstrxy(double, double, char s[]);

void ticxy();

void HVlabel();

void print(double, double, double);

double round(double);

void initialization();

void initialization();

{

printf("Input the coordinates of the viewport(vx1,vy1,vx2,vy2)");

printf("ex) 100 60 550 400 ");

scanf("%d %d %d %d",&vx1,&vy1,&vx2,&vy2);

printf("the coordinates of the window (wx1,wy1,wx2,wy2)");

printf("ex) -0.5 -2.0 0.5 2.0 ");

scanf("%lf %lf %lf %lf",&wx1,&wy1,&wx2,&wy2);

printf("the information of the ticx (txi,ticx,ix)");

printf("txi: position of the initial tic on the x-axis ");

printf("ticx: interval between the tic's ");

printf("ix: the value of the x coordinate at every (ix)th tic is shown");

printf("ex) -0.5 0.25 1 ");

scanf("%lf %lf %d",&txi,&ticx,&ix);

printf("the information of the ticy (tyi,ticy,iy)");

printf("tyi: position of the initial tic on the y-axis ");

printf("ticy: interval between the tic's ");

printf("iy: the value of the y coordinate at every (iy)th tic is shown");

printf("ex) -2.0 1.0 1 ");

scanf("%lf %lf %d",&tyi,&ticy,&iy);

printf("the information of the floating point to");

printf(" ticx(%%f,%%s) and ticy(%%f,%%s)");

printf("%%5.2f: print as floating point, at least 5 wide and 2 after");

5.graph.h

void draw(double x1,double y1,double x2,double y2)

{

int ix1,iy1,ix2,iy2;

double u1,v1,u2,v2;

u1 = (x1-wx1)/(wx2-wx1)*(vx2-vx1);

v1 = (wy2-y1)/(wy2-wy1)*(vy2-vy1);

u2 = (x2-wx1)/(wx2-wx1)*(vx2-vx1);

v2 = (wy2-y2)/(wy2-wy1)*(vy2-vy1);

if( fabs(u1) > c || fabs(v1) > c || fabs(u2) > c || fabs(v2) > c )

exit(-1);

ix1 = round(u1); iy1 = round(v1); ix2 = round(u2); iy2 = round(v2);

line(ix1,iy1,ix2,iy2);

}

void drawxy(double x,double y)

{

int ix,iy;

double u,v;

u = (x-wx1)/(wx2-wx1)*(vx2-vx1);

v = (wy2-y)/(wy2-wy1)*(vy2-vy1);

if( fabs(u) > c || fabs(v) > c ) exit(-1);

ix = round(u); iy = round(v);

lineto(ix,iy);

}

void outstrxy(double x,double y,char s[])

{

int ix, iy;

double u,v;

u = (x-wx1)/(wx2-wx1)*(vx2-vx1);

v = (wy2-y)/(wy2-wy1)*(vy2-vy1);

if( fabs(u) > c || fabs(v) > c ) exit(-1);

ix = round(u); iy = round(v);

outtextxy(ix,iy,s);

}

printf(" decimal point; [ex) -1.22 -> %%5.2f, -1.222 -> %%6.3f] ");

printf("%%5s: print as characters, at least 5 wide;");

printf(" [ex)-1.22 -> %%5s, -1.222 -> %%6s]");

printf("ex) %%5.2f %%5s %%6.3f %%6s");

scanf("%s %s %s %s",f1,f2,f3,f4);

printf("(tic_in = 1 or tic_out = 0)");

printf("(tic_in [tic_out]: tic's are shown inside [outside] the frame.)");

scanf("%d",&select);

printf("(tic_up_right = 1 or not = 0)");

printf("(The tics are always shown on the left and bottom axis; however,");

printf(" the tics on the right and top axis are optional.)");

scanf("%d",&select1);

printf("the label on the horizontal axis");

scanf("%s",H);

printf("the label on the vertical axis");

scanf("%s",V);

}

double round(double x)

{

return(( x>0 ) ? floor(x + .5) : ceil(x - .5));

}

void plot(double x, double y,int color)

{

int ix,iy;

double u,v;

u = (x-wx1)/(wx2-wx1)*(vx2-vx1);

v = (wy2-y)/(wy2-wy1)*(vy2-vy1);

if( fabs(u) > c || fabs(v) > c ) exit(-1);

ix = round(u); iy = round(v);

putpixel(ix,iy,color);

}

void ticxy()

{

char s[20],buf[20];

i nt I;

double ticxl,ticyl,x1,y1,x2,y2,x22,y22;

ticxl = 6.0 * (wy2-wy1)/(vy2-vy1);

ticyl = 6.0 * (wx2-wx1)/(vx2-vx1);

x1 = txi; y1 = wy1; x2 = x1;

I = 0;

settextstyle(DEFAULT_FONT,HORIZ_DIR,1);

if(select == 0)

y2 = y1-ticxl*2;

y22 = y1-ticxl;

do

{

draw(x1,y1,x2,y2); if(select1 == 1) draw(x1,wy2,x2,wy2+ticxl*2);

if(x1+ticx/2 <= wx2)

draw(x1+ticx/2,y1,x2+ticx/2,y22);

if(select1 == 1) draw(x1+ticx/2,wy2,x2+ticx/2,wy2+ticxl);

}

if(I%ix == 0) {

sprintf(buf,f1,x1);

sscanf(buf,f2,s);

outstrxy(x1,y2-1.5*ticxl,s);

/* if(select1 == 1) outstrxy(x1,wy2+ticxl*2+1.5*ticxl,s);*/

x1 = x1+ticx; x2 = x1;

I++;

} while(x1 <= wx2);

}

else{

y2 = y1+ticxl*2;

y22 = y1+ticxl;

do{

draw(x1,y1,x2,y2); if(select1 == 1) draw(x1,wy2,x2,wy2-ticxl*2);

if(x1+ticx/2 <= wx2){

draw(x1+ticx/2,y1,x2+ticx/2,y22);

if(select1 == 1) draw(x1+ticx/2,wy2,x2+ticx/2,wy2-ticxl);

}

if(I%ix == 0){

sprintf(buf,f1,x1);

sscanf(buf,f2,s);

outstrxy(x1,y1-4*ticxl,s);

/* if(select1 == 1) outstrxy(x1,wy2+4*ticxl,s);*/

}

x1 = x1+ticx; x2 = x1;

I++;

} while(x1 <= wx2);

}

y1=tyi; x1=wx1; y2=y1;

I = 0;

settextstyle(DEFAULT_FONT,VERT_DIR,1);

Do{

draw(x1,y1,x2,y2);

if(select1 == 1) draw(wx2,y1,wx2-ticyl*2,y2);

if(y1+ticy/2 <= wy2){

draw(x1,y1+ticy/2,x22,y2+ticy/2);

if(select1 == 1) draw(wx2,y1+ticy/2,wx2-ticyl,y2+ticy/2);

if(I%iy == 0){

sprintf(buf,f3,y1);

sscanf(buf,f4,s);

outstrxy(x1-4*ticyl,y2,s);

/* if(select1 == 1) outstrxy(wx2+4*ticyl,y2,s);*/ }

y1 = y1+ticy; y2 = y1;

I++;

} while(y1 <= wy2);}

}

void HVlabel()

{

double hl,vl,xh,yh;

hl = 11.0 * (wy2-wy1)/(vy2-vy1);

vl = 11.0 * (wx2-wx1)/(vx2-vx1);

xh = wx1 + 0.5*(wx2-wx1);

yh = wy1 + 0.5*(wy2-wy1);

settextstyle(DEFAULT_FONT,HORIZ_DIR,1);

outstrxy(xh,wy1-5.0*hl,H);

settextstyle(DEFAULT_FONT,VERT_DIR,1);

outstrxy(wx1-5.0*vl,yh,V);

}

if(select == 0){

x2 = x1-ticyl*2;

x22 = x1-ticyl;

do{

draw(x1,y1,x2,y2); if(select1 == 1) draw(wx2,y1,wx2+ticyl*2,y2);

if(y1+ticy/2 <= wy2){

draw(x1,y1+ticy/2,x22,y2+ticy/2);

if(select1 == 1) draw(wx2,y1+ticy/2,wx2+ticyl,y2+ticy/2);

}

if(I%iy == 0){

sprintf(buf,f3,y1);

sscanf(buf,f4,s);

outstrxy(x2-1.5*ticyl,y2,s);

/* if(select1 == 1) outstrxy(wx2+ticyl*2+1.5*ticyl,y2,s);*/ }

y1 = y1+ticy; y2 = y1;

I++;

} while(y1 <= wy2);

}

else{

x2 = x1+ticyl*2;

x22 = x1+ticyl;