Encoding and cropping Algorithm

Encoding and cropping Algorithm
Draw a window with any color, draw a line segment with a color, and crop the line segment using the encoding cropping algorithm. The cropping process must be demonstrated. The image before cropping should be drawn. When any button is pressed, the cropping result should be drawn. Use TC to open the source program:
# Include <stdio. h>
# Include <graphics. h>
# Define LEFT 1
# Define RIGHT 2
# Define BOTTOM 4
# Define TOP 8
# Define FALSE 0
# Define TRUE 1
Void Line_Clipping (x1, y1, x2, y2, xw_xmin, yw_ymin, xw_xmax, yw_ymax)
Float x1, y1, x2, y2, xw_xmin, yw_ymin, xw_xmax, yw_ymax;
{
Int draw, done;
Int code1, code2, code;
Float x, y;
Draw = FALSE; done = FALSE;
Code1 = get_code (x1, y1, xw_xmin, yw_ymin, xw_xmax, yw_ymax );
Code2 = get_code (x2, y2, xw_xmin, yw_ymin, xw_xmax, yw_ymax );
While (! Done)
{
If (code1 = 0 & code2 = 0)
{
Draw = TRUE; done = TRUE;
}
Else if (code1 & code2! = 0)
{
Done = TRUE;
} Else
{
If (code1! = 0)
Code = code1;
Else
Code = code2;
If (code & TOP )! = 0)
{Y = yw_ymax;
X = x1 + (y-y1) * (x2-x1)/(y2-y1 );

}
Else if (code & BOTTOM )! = 0)
{
Y = yw_ymin;
X = x1 + (y-y1) * (x2-x1)/(y2-y1 );
}
Else if (code & RIGHT )! = 0)
{
X = xw_xmax;
Y = y1 + (x-x1) * (y2-y1)/(x2-x1 );
}
Else if (code & LEFT )! = 0)
{
X = xw_xmin;
Y = y1 + (x-x1) * (y2-y1)/(x2-x1 );
}
If (code = code1)
{
X1 = x;
Y1 = y;
Code1 = get_code (x1, y1, xw_xmin, yw_ymin, xw_xmax, yw_ymax );
}
Else
{
X2 = x;
Y2 = y;
Code2 = get_code (x2, y2, xw_xmin, yw_ymin, xw_xmax, yw_ymax );
}
}
If (draw)
{
Setcolor (8 );
Line (x1, y1, x2, y2 );
}
}
}
Int get_code (x, y, xw_xmin, yw_ymin, xw_xmax, yw_ymax)
Float x, y, xw_xmin, yw_ymin, xw_xmax, yw_ymax;
{
Int code;
Code = 0;
If (y> yw_ymax)
Code | = TOP;
Else if (y <yw_ymin)
Code | = BOTTOM;
If (x> xw_xmax)
Code | = RIGHT;
Else if (x <xw_xmin)
Code | = LEFT;
Return code;
}
Void main ()
{
Float x1 = 76, y1 = 40, x2 = 60, y2 = 80, xw_xmin = 50, xw_xmax = 80, yw_ymin = 50, yw_ymax = 70;
Int gdriver = DETECT, gmode;
Initgraph (& gdriver, & gmode, "C: \ TURBOC2 ");
Setcolor (5 );
Line (x1, y1, x2, y2 );
Rectangle (xw_xmin, yw_ymin, xw_xmax, yw_ymax );
Getch ();
Cleardevice ();
Setcolor (8 );
Rectangle (xw_xmin, yw_ymin, xw_xmax, yw_ymax );
Line_Clipping (x1, y1, x2, y2, xw_xmin, yw_ymin, xw_xmax, yw_ymax );
Getch ();
Closegraph ();
}

From pzhsunxu's column