There are three main methods for generating characters using software in computer graphics: 1) The stroke method uses a sequence of line and arc drawing functions to generate characters by assigning start and end points. It can generate various fonts but produces aliased characters for diagonals. 2) The bitmap method stores character pixel data in an array and plots each pixel to generate the character. It can easily generate various fonts and sizes but also produces aliased characters. 3) The starburst method uses a fixed pattern of 24 line segments represented by bits to highlight lines and generate characters. It requires extra memory for the bit patterns and produces lower quality characters due to its limited templates.

1. Character Generation Techniques
Computer Graphics

2. Characters Generation in CG
– In computer graphics character can be generated using software.
– In hardware implementation of character generation limited faces of
character can be generated.
– A wide variety of faces of character can be generated with software
implementation.
– There are three methods for generating characters using software
implementation.
– Stroke method
– Vector method or bitmap method.
– Star bust method

3. Stoke method
•
•
•
In this method we use a sequence of line drawing function and arc
functions to generate characters.
We can generate a sequence of character by assigning starting and
end point of line or arc.
By using this method various faces of character can be generated
by changing the values (parameters) in line and arc function.

4. Stoke method
• The main disadvantage of this method is when we draw a diagonal line it
produce aliased character.

5. Bitmap Method

6. Program For Bitmap Method
• #include<stdio.h>
• #include<conio.h>
• #include<graphics.h>
• main()
• {
• int gd,gm,i,j;
{ 0, 0, 0, 0, 1, 0, 0, 0, 0},
{ 0, 0, 0, 1, 0, 1, 0, 0, 0},
{ 0, 0, 1, 0, 0, 0, 1, 0, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 1, 1, 1, 1, 1, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
{ 0, 1, 0, 0, 0, 0, 0, 1, 0},
int a[13][9] = {
•
•
•
•
•
•
•
•
•
•
•
•
•
• };
/* Initialise graphics mode */
detectgraph(&gd,&gm);
initgraph(&gd,&gm,"c:tcbgi");
•
•
•
•
for(i=0;i<13;i++)
{
for(j=0;j<9;j++)
{
putpixel(200+j,200+i,15*a[i][j]);
}
}
getch();
closegraph();
}

7. Bitmap Method
• This method is suitable for producing various
character.
• Font size of character can be increased by
increasing the size of array.
• The main draw back of this method is this
method produce aliased character.

8. Starbust Method
1. In this method a fixed pattern of line is used to generate the
character.
2. In this method we use a combination of 24 bit line segment.
3. In 24 bit line segment code each bit represent a single line.
4. To highlight a line we put corresponding bit 1 in 24 bit line
segment code and 0 otherwise.

9. Starbust Method
Disadvantages of starbust method
24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
0 1 0 1 1 1 0 1 0 1 0 1 1 0 0 0 1 1 0 1 0 1 0 1
24 bit line segment code
1. Here in this method 24 bit segment code is required to put in
memory for generating character. Hence extra memory is
required in this method.
2. Character quality is poor due to limited face.

10. THANK YOU!!