Merge pull request #151 from rahulkumaran/rahulkumaran-graphics_algos

Graphics Folder with an implementation of DDA Line Algo in C

Author: prateekiiest

Graphics Algos/README.md

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+## GRAPHICS ALGORITHMS
+
+This is a folder which contains graphics algorithms and their implementations.
+
+### Robo.c
+
+The robo.c program is a program which helps you in drawing a robot.
+The robot is drawn around a reference point. The DDA Line Algorithm was used in making the program.
+The DDA Line algorithm exists inside the program in a function so you can have a look at what the DDA line algorithm is,
+inside this program itself.<br><br>
+The image below shows the Output of the program!
+
+![picture](https://user-images.githubusercontent.com/26206171/33807711-e08a11ca-de00-11e7-8635-78aa0f8a2884.png)

Graphics Algos/robo.c

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+#include <graphics.h>
+
+float FX,FY,BX,BY,ax,bx,ay,by;
+
+void DDALine(float x1,float y1,float x2,float y2)
+{
+  float x,y,dx,dy,step;
+  if(x1>x2 || y1>y2)
+  {
+    x1=x1+x2;x2=x1-x2;x1=x1-x2; //  x1 x2 swap
+    y1=y1+y2;y2=y1-y2;y1=y1-y2; //  y1 y2 swap
+  }
+  dx=abs(x2-x1); //finding the positive difference between x1 and x2
+  dy=abs(y2-y1); //finding positive difference between y1 and y2
+  if(dx>=dy)
+    step=dx;
+  else
+    step=dy;
+  dx/=step;
+  dy/=step;
+  x=x1;
+  y=y1;
+  for(int i=0;i<=step;i++)
+  {
+    putpixel(x,y,WHITE);
+    x+=dx;
+    y+=dy;
+  }
+}
+void DDARect(float x1,float y1,float x2,float y2) //Creating a rectangle using dda line
+{
+  DDALine(x1,y1,x2,y1); 
+  DDALine(x2,y1,x2,y2);
+  DDALine(x2,y2,x1,y2);
+  DDALine(x1,y1,x1,y2);
+}
+void main( )
+{
+  BX=320; BY=240; FX=BX; FY=BY-60; //BX and BY are some constants to make sure we place the robo somewhere in the centre of screen
+  int gd=DETECT,gm;			// FX and FY are translating constants to make sure all parts of the body are drawns
+  initgraph(&gd,&gm,"NULL");
+  //--Head
+  //Cap
+  circle(FX,FY-40,5);
+  DDARect(FX-2.5,FY-25,FX+2.5,FY-35);
+  arc(FX,FY-20,180,360,5);
+  //Face
+  DDARect(FX-20,FY+20,FX+20,FY-20);//Face Outline
+  DDARect(FX-15,FY,FX-5,FY-10);//Left Eye
+  DDARect(FX+5,FY,FX+15,FY-10);//Right Eye
+  //Mouth
+  DDARect(FX-10,FY+15,FX+10,FY+10);
+  //TEETH
+  DDARect(FX-2,FY+15,FX+2,FY+10);
+  DDARect(FX-6,FY+15,FX+6,FY+10);
+  //LEFT_EAR
+  DDARect(FX-25,FY,FX-20,FY-10);
+  DDARect(FX-30,FY-2.5,FX-25,FY-7.5);
+  //RIGHT_EAR
+  DDARect(FX+25,FY,FX+20,FY-10);
+  DDARect(FX+25,FY-2.5,FX+30,FY-7.5);
+  DDARect(BX-5,BY-30,BX+5,BY-40);//Neck
+  //--BODY
+  DDARect(BX-30,BY+30,BX+30,BY-30); // Body Outline
+  DDARect(BX-20,BY+15,BX+20,BY-20); // Inner Square
+  DDARect(BX-25,BY+70,BX-10,BY+30); //  Left Leg
+  arc(BX-17.5,BY+70,180,360,7.5);  // Left Foot
+  DDARect(BX+25,BY+70,BX+10,BY+30); //  Right Leg
+  arc(BX+17.5,BY+70,180,360,7.5); //  Right Foot
+  //Left_Hand
+  ax=BX-47,ay=BY-5; //ax and bx become relative points to draw both hands 
+  bx=BX-47,by=BY+5;
+  for(int i=0;i<10;i++)
+  {
+        putpixel(ax,ay,WHITE);
+	putpixel(bx,by,WHITE);
+        ax+=1.7;
+	bx+=1.7;
+	ay-=1;
+	by-=1;
+  }
+  circle(BX-47,BY,5);
+  //Right_Hand
+  DDALine(BX+47,BY-5,BX+30,BY-15);
+  DDALine(BX+47,BY+5,BX+30,BY-5);
+  circle(BX+47,BY,5);
+  ax=BX+47,ay=BY-5;
+  bx=BX+47,by=BY+5;
+  //END
+  delay(5000);
+  getch();
+}