the GEEK

We require three dimensional geometric and co-ordinate transformation to change the view of a three dimensional object.Three dimensional transformations are extended from two dimensional transformations by considering the 'z' co-ordinate also in the plane.Just like two dimensional transformation in three dimensional transformations are formed by composing three basic transformations of translation, scaling and rotation. Here we are going to discuss about the scaling. What is scaling? A scaling transform can be used to make objects bigger or smaller. Mathematically, a scaling transform simply multiplies each x-coordinate by a given amount and each y-coordinate by a given amount. That is, if a point ( x , y ) is scaled by a factor of a in the x direction and by a factor of d in the y direction, then the resulting point ( x1 , y1 ) is given by                        ...

We require three dimensional geometric and co-ordinate transformation to change the view of a three dimensional object.Three dimensional transformations are extended from two dimensional transformations by considering the 'z' co-ordinate also in the plane.Just like two dimensional transformation in three dimensional transformations are formed by composing three basic transformations of translation, scaling and rotation. Here we are going to discuss about the translation. What is translation? A translation transform simply moves every point by a certain amount horizontally and a certain amount vertically. If ( x , y ) is the original point and ( x1 , y1 ) is the transformed point, then the formula for a translation is-                           x1=x+e                   ...

This generally happens with all of us.We save our password of websites in our browser and forget it later. Although when we open that website we don't need to enter the password.But if we want to know what is the password we see only ( ......... ) in our password section even after we logout from our dashboard. It is very easy to find these password.Follow the steps given below-     Open the login section of the website whose password you want to retrieve. Suppose we are retrieving the password of facebook.If password is saved you will not get login window, so logout from your account and you will see a window like this-                                                                                           ...

Compilation of a C program is a four stage process- Preprocessing (creates file.i ) Compilation (creates file.s ) Assembly (creates file.o ) Linking (creates executable file ) Note- when we will generate all intermediate files for a cpp program preprocessing generates file.ii while other are same as C program intermediate files.   We will discuss details of these steps later.First of all make a .c or .cpp file-   Open your terminal and type this command-                           gedit hello.c      and write the following code in this file. After saving this type this command in your terminal-                 gcc -save-temps hello hello.c (for .c file)                g++ -save-temps hello hello.cpp (for .cpp file) Now open your folder where you have created the progra...

When we run C program it loaded into the ram in a very organized fashion.There are various segments to store code data and code instructions. The memory layout of a C program consist following sections- Text or code segment Initialized Data segment Uninitialized Data segment or .bss segment Heap segment  Stack segment Command line argumets Text or Code segment - It is the segment in memory which contains executable instructions or compiled program(./a.out or .exe file). Usually, the text segment is sharable so that only a single copy needs to be in memory for frequently executed programs, such as text editors, the C compiler, the shells, and so on. Also, the text segment is often read-only, to prevent a program from accidentally modifying its instructions.   Initialized data segment- It is basically a data segment which contains all global , static , constant , external (variable with extern keyword) variables that are initialized in the program. This is not just a read-...

Definition- A header linked list is a type of linked list which always contains a special node called the header node at the very beginning of the linked list.It is an extra node kept at the front of a list. Such a node does not represent an item in the linked list.The information part of this node can be used to store any global information about the whole linked list.   Source- pages.cs.wisc.edu Advantages of having a header node-   In header node, you can maintain count variable which gives number of nodes in the list. You can update header node count member whenever you add /delete any node. It will help in getting list count without traversing in O(1) time. In addition to address of first node you can also store the address of last node. So that if you want to insert node at the rear end you don't have to iterate from the beginning of the list. Also in tcase of DLL(Doubly Linked List) if you want to traverse from rear end it helps. We can also use it to store the poi...

DDA algorithm is the basic algorithm for line drawing.In this method, we start from the starting point and then on each step a fixed increment is added to the current point to get the next point on the line.We repeat these steps till the end of the line. Let us suppose (x1,y1) and (x2,y2) are the end points of the line and the equation of the line is y=mx+c.                  slope of the line=(y2-y1)/(x2-x1)                  suppose dx=(x2-x1) and dy=(y2-y1)                  dx=dy/m    and     dy=m*dx dx and dy will be the values for incrementing x and y values of current point.so-                          X i+1 =X i + dy/m                          Y i+1 =Y i + m*dx DDA Algorithm-  Read the points (x...

In Mid-point Ellipse drawing algorithm we use 4 way symmetry of the ellipse to generate it.We perform calculations for one part and the other three parts will be drawn by using 4-way symmetry. For given parameter Rx and Ry (radii of ellipse) and (Xc,Yc)-center of ellipse, we determine the point (x,y) for an ellipse in standard position centered on the origin and then we shift the points so the ellipse is centered at (Xc,Yc). We can see the image given below, how we choose next point.  Source- www.slideshare.net Algorithm- Read the two radii Rx and Ry Initialize starting point x=0,y=Ry Calculate initial decision variable for region 1                   d1=Ry*Ry-Rx*Rx*Ry-(Rx*Rx)/4 Region 1      do{                   plot(x,y) and other 3 symmetric points                   if(d1<0)     ...

Transformation of any object in a 2D or 3D plane means the change in the looks of the object by applying certain rules.  Scaling- It is one of the transformation technique. Scaling changes the size of an object.This operation is carried out in any polygon by multiplying the scaling factor (Sx,Sy) with each vertex coordinate value (x,y) of the polygon.This results in transform coordinates (x',y') and then we plot the transformed coordinates. Here is the program to scale a triangle so  Let's suppose (x1,y1) (x2,y2) (x3,y3) are the coordinates of a triangle and the scaling factor is (Sx,Sy) then transform coordinates will be-                      (x1',y1')=(Sx*x1,Sy*y1)                      (x2',y2')=(Sx*x2,Sy*y2)                       (x3',y3')=(Sx*x3,Sy*y3)   One thing you need to keep in mind that th...

Flood Fill Algorithm- Flood fill algorithm is used to color the polygon.This comes under seed fill algorithm.To color a polygon we use either 4-connected method or 8-connected method.   4-connected method- In this method, we choose a seed pixel and color it with new color after this we color the neighbourhood pixels and so on. 8-connected method- In this method, we choose a seed pixel and color it with new color after this we color all eight neighbourhood pixels and so on. we can see this by this picture- Source-https://www.cs.auckland.ac.nz/courses/compsci773s1c/lectures/ImageProcessing-html/neighbourhoods.gif Here is the c++ program for flood fill algorithm- #include<bits/stdc++.h> #include<graphics.h> using namespace std; //function to implement floodfill algorithm void floodfill(int x,int y,int old,int newcol) { //getpixel() gives the color of pixel (x,y) int curr=getpixel(x,y); //if the color of current pixel is same as the old color then color this to new colo...