Presentation about computer graphics and visualization also code for dancing doll in C/C++

1. COMPUTER GRAPHICS -
DANCING DOLL

2. BASICS:
Computer graphics is an art of drawing pictures on computer screens with the help
of programming and algorithms. It involves computations, creation, and
manipulation of data. In other words, we can say that computer graphics is a
rendering tool for the generation and manipulation of images.
Application of Computer Graphics
1.Computer graphics user interfaces (GUIs). 2.Business presentation graphics
3.Cartography Weather Maps 4.Satellite Imaging Photo Enhancement
5.Medical Imaging 6.Engineering drawings
7.Typography 8.Architecture Art
9.Entertainment 10.Simulation and modeling

3. GRAPHICS.H
Used to draw different shapes, display text in different fonts, change colors and many more. Using functions of
graphics.h in Turbo C compiler you can make graphics programs, animations, projects, and games. You can draw
circles, lines, rectangles, bars and many other geometrical figures. You can change their colors using the available
functions and fill them. Following is a list of functions of graphics.h header file. Every function is discussed with the
arguments it needs, its description
GRAPHICS.H FUNCTIONS
arc bar bar3d circle
cleardevice closegraph drawpoly ellipse
fillellipse fillpoly floodfill getarccords
getbkcolor getcolor getdrivername getimage
getmaxcolor getmaxx getmaxy getpixel
getx gety graphdefaults grapherrormsg
imagesize line lineto linerel
moveto moverel outtext outtextxy
pieslice putimage putpixel rectangle
sector setbkcolor setcolor setfillstyle
setlinestyle settextstyle setviewport textheight textwidth

4. BASICS: LINE GENERATION ALGORITHM
In any 2-Dimensional plane if we connect two points (x0, y0) and (x1, y1), we get a line segment. But in the
case of computer graphics we can not directly join any two coordinate points, for that we should
CALCULATE INTERMEDIATE POINT’S COORDINATE and put a pixel for each intermediate point, of
the desired color with help of functions like putpixel(x, y, K) in C, where (x,y) is our co-ordinate and K
denotes some color
 DDAALGORITHM
 BRESENHAM’S LINE GENERATION
 MID-POINT ALGORITHM

5. DDA- LINE GENERATION ALGORITHM
Consider one point of the line as (X0,Y0) and the second point of the line as (X1,Y1).
// calculate dx , dy
dx = X1 - X0;
dy = Y1 - Y0;
// Depending upon absolute value of dx & dy
// choose number of steps to put pixel as
// steps = abs(dx) > abs(dy) ? abs(dx) : abs(dy)
steps = abs(dx) > abs(dy) ? abs(dx) : abs(dy);
// calculate increment in x & y for each steps
Xinc = dx / (float) steps;
Yinc = dy / (float) steps;
// Put pixel for each step
X = X0;
Y = Y0;
for (int i = 0; i <= steps; i++)
{
putpixel (X,Y,WHITE);
X += Xinc;
Y += Yinc;
}

6. BASICS: CIRCLE GENERATION ALGORITHM
 Drawing a circle on the screen is a little complex than drawing a line. There are two popular
algorithms for generating a circle: Bresenham’s Algorithm and Midpoint Circle Algorithm.
These algorithms are based on the idea of determining the subsequent points required to draw
the circle. Bresenham’s Algorithm:
Step 1 − Get the coordinates of the center of the circle and radius, and store them in
x, y, and R respectively. Set P=0 and Q=R.
Step 2 − Set decision parameter D = 3 – 2R.
Step 3 − Repeat through step-8 while P ≤ Q.
Step 4 − Call Draw Circle X,Y,P,QX,Y,P,Q.
Step 5 − Increment the value of P.
Step 6 − If D < 0 then D = D + 4P + 6.
Step 7 − Else Set R = R - 1, D = D + 4P−QP−Q + 10.
Step 8 − Call Draw Circle X,Y,P,Q.
putpixel (X + P, Y + Q)
putpixel (X - P, Y + Q)
putpixel (X + P, Y - Q)
putpixel (X - P, Y - Q)
putpixel (X + Q, Y + P)
putpixel (X - Q, Y + P)
putpixel (X + Q, Y - P)
putpixel (X - Q, Y - P)

7. BASICS: POLYGON FILLING
Polygon is an ordered list of vertices as shown in the following figure. For filling polygons with
particular colors, you need to determine the pixels falling on the border of the polygon and
those which fall inside the polygon.
Scan Line Algorithm
Flood Fill Algorithm
Boundary Fill Algorithm
4-Connected Polygon
8-Connected Polygon
Inside-outside Test : 1. Odd-Even Rule 2.Nonzero winding number rule

8. COMPUTER ANIMATION
The basic idea behind animation is to play back the recorded images at the rates fast enough to
fool the human eye into interpreting them as continuous motion. Animation can make a series of
dead images come alive. Animation can be used in many areas like entertainment, computer
aided-design, scientific visualization, training, education, e-commerce, and computer art.
Traditional Animation (frame by frame) : Key Framing
 A keyframe is a frame where we define changes in animation. Every frame is a keyframe when we
create frame by frame animation. When someone creates a 3D animation on a computer, they usually
don’t specify the exact position of any given object on every single frame. They create keyframes.
 Keyframes are important frames during which an object changes its size, direction, shape or other
properties. The computer then figures out all the in-between frames and saves an extreme amount of
time for the animator. The following illustrations depict the frames drawn by user and the frames
generated by computer.

9. DANCING DOLL: Visualization
Initial position

10. DANCING DOLL: CODE & OUTPUT

11. DANCING DOLL: DANCING DOLL