This assignment requires writing a simple “Paint” program. Part of the assignmen
ID: 667568 • Letter: T
Question
This assignment requires writing a simple “Paint” program. Part of the assignment is also to demonstrate encapsulation, so we begin with a brief discussion of the approach to this assignment.
There are several graphics libraries available for all the common operating systems, and each provides its own idiosyncrasies. We are going to attempt to design a class that will hide the details of any specific graphics library, thus potentially letting developers use our class without having to “relearn” a new graphics programming model. To do this, we need to consider what high-level operations we want to provide, or need to provide. Let’s start with some basic operations (in the context of a “Paint” program):
Define a generic drawing surface as a “canvas,” with the intent that a user draws on the canvas and can erase the canvas.
Support the notion of a “drawing” or “painting” that will capture all the points (or pixels) that we want to draw, and then we can do things such as “refresh” the drawing when we need to.
Only allow drawing points for now, and only support white pixels on a black background.
Explanation / Answer
working c++ program
#include<graphics.h>
#include<dos.h>
#include<math.h>
#include<stdlib.h>
#include<stdio.h>
#include<conio.h>
union REGS i, o;
int leftcolor[15];
int get_key()
{
union REGS i,o;
i.h.ah = 0;
int86(22,&i,&o);
return ( o.h.ah );
}
void draw_color_panel()
{
int left, top, c, color;
left = 100;
top = 436;
color = getcolor();
setcolor(GREEN);
rectangle(4,431,635,457);
setcolor(RED);
settextstyle(TRIPLEX_FONT,0,2);
outtextxy(10,431,"Colors : ");
for( c = 1 ; c <= 15 ; c++ )
{
setfillstyle(SOLID_FILL, c);
bar(left, top, left+16, top+16);
leftcolor[c-1] = left;
left += 26;
}
setcolor(color);
}
void draw_shape_panel()
{
int left, top, c, color;
left = 529;
top = 45;
color = getcolor();
setcolor(GREEN);
rectangle(525,40,633,255);
for( c = 1 ; c <= 7 ; c++ )
{
rectangle(left, top, left+100, top+25);
top += 30;
}
setcolor(RED);
outtextxy(530,45,"Bar");
outtextxy(530,75,"Line");
outtextxy(530,105,"Pixel");
outtextxy(530,135,"Ellipse");
outtextxy(530,165,"Freehand");
outtextxy(530,195,"Rectangle");
outtextxy(530,225,"Clear");
setcolor(color);
}
void change_color(int x, int y)
{
int c;
for( c = 0 ; c <= 13 ; c++ )
{
if( x > leftcolor[c] && x < leftcolor[c+1] && y > 437 && y < 453 )
setcolor(c+1);
if( x > leftcolor[14] && x < 505 && y > 437 && y < 453 )
setcolor(WHITE);
}
}
char change_shape(int x, int y)
{
if ( x > 529 && x < 625 && y > 45 && y < 70 )
return 'b';
else if ( x > 529 && x < 625 && y > 75 && y < 100 )
return 'l';
else if ( x > 529 && x < 625 && y > 105 && y < 130 )
return 'p';
else if ( x > 529 && x < 625 && y > 135 && y < 160 )
return 'e';
else if ( x > 529 && x < 625 && y > 165 && y < 190 )
return 'f';
else if ( x > 529 && x < 625 && y > 195 && y < 220 )
return 'r';
else if ( x > 529 && x < 625 && y > 225 && y < 250 )
return 'c';
}
void showmouseptr()
{
i.x.ax = 1;
int86(0x33,&i,&o);
}
void hidemouseptr()
{
i.x.ax = 2;
int86(0x33,&i,&o);
}
void restrictmouseptr( int x1, int y1, int x2, int y2)
{
i.x.ax = 7;
i.x.cx = x1;
i.x.dx = x2;
int86(0x33,&i,&o);
i.x.ax = 8;
i.x.cx = y1;
i.x.dx = y2;
int86(0x33,&i,&o);
}
void getmousepos(int *button,int *x,int *y)
{
i.x.ax = 3;
int86(0x33,&i,&o);
*button = o.x.bx;
*x = o.x.cx;
*y = o.x.dx;
}
main()
{
int gd = DETECT,gm;
int maxx,maxy,x,y,button,prevx,prevy,temp1,temp2,key,color;
char ch = 'f' ; // default free-hand drawing
initgraph(&gd,&gm,"C:\TC\BGI");
maxx = getmaxx();
maxy = getmaxy();
setcolor(BLUE);
rectangle(0,0,maxx,maxy);
setcolor(WHITE);
settextstyle(SANS_SERIF_FONT,HORIZ_DIR,2);
outtextxy(maxx/2-180,maxy-28,"<a href="http://www.programmingsimplified.com"">www.programmingsimplified.com"</a>);
draw_color_panel();
draw_shape_panel();
setviewport(1,1,maxx-1,maxy-1,1);
restrictmouseptr(1,1,maxx-1,maxy-1);
showmouseptr();
rectangle(2,2,518,427);
setviewport(1,1,519,428,1);
while(1)
{
if(kbhit())
{
key = get_key();
if( key == 1 )
{
closegraph();
exit(0);
}
}
getmousepos(&button,&x,&y);
if( button == 1 )
{
if( x > 4 && x < 635 && y > 431 && y < 457 )
change_color( x, y );
else if ( x > 529 && x < 625 && y > 40 && y < 250 )
ch = change_shape( x, y );
temp1 = x ;
temp2 = y ;
if ( ch == 'f' )
{
hidemouseptr();
while( button == 1 )
{
line(temp1,temp2,x,y);
temp1 = x;
temp2 = y;
getmousepos(&button,&x,&y);
}
showmouseptr();
}
while( button == 1)
getmousepos(&button,&x,&y);
/* to avoid interference of mouse while drawing */
hidemouseptr();
if( ch == 'p')
putpixel(x,y,getcolor());
else if ( ch == 'b' )
{
setfillstyle(SOLID_FILL,getcolor());
bar(temp1,temp2,x,y);
}
else if ( ch == 'l')
line(temp1,temp2,x,y);
else if ( ch == 'e')
ellipse(temp1,temp2,0,360,abs(x-temp1),abs(y-temp2));
else if ( ch == 'r' )
rectangle(temp1,temp2,x,y);
else if ( ch == 'c' )
{
ch = 'f'; // setting to freehand drawing
clearviewport();
color = getcolor();
setcolor(WHITE);
rectangle(2,2,518,427);
setcolor(color);
}
showmouseptr();
}
}
}
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