For this program continue to modify your graphics project.

• Add a data structure to store the input objects.

• Add a command in the form:

  	window  x1 y1 x2 y2
  

  This command should set up a window into world coordinate system. The default values should 0,0 and 10,10

• Add a command in the form:

       viewport n x1 y1 x2 y2
  

  This command will set the coordinates in NDC space for viewport n. Divide your output window into four equal areas. The areas will correspond to values of n=0,1,2,3. The default values should be:

  	     Viewport   Xmin   Ymin   Xmax   Ymax
  		0         0      0     .5     .5
  		1         0      .5    .5      1
  		2        .25    .25    .75    .75
  		3         0      0      1      1
  

  And the viewports should be mapped as follows

  		     	   Top of Output Window
  		    ----------------------------------
      VP0Xmin, VP0Ymax|               |                |VP1Xmax, VP1Ymax
  		    |               |                |
  		    |               |                |
  		    |       0       |       1        |
  		    |               |                |
      VP0Xmin, VP0Ymin|               |                |VP1Xmax, VP1Ymin
  		    ----------------------------------
      VP2Xmin, VP2Ymax|               |                |VP3Xmax, VP3Ymax
  		    |               |                |
  		    |               |                |
  		    |       2       |       3        |
  		    |               |                |
      VP2Xmin, VP2Ymin|               |                |VP3Xmax, VP3Ymin
  		    ----------------------------------
  

• Implement all of the above commands and a complete two dimensional graphics transformation pipeline. You will need to implement point, line and polygon clipping. You need not implement circle clipping.