Character generation
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This document discusses three methods for generating characters in computer graphics: the stroke method, bitmap method, and starburst method. The stroke method uses line and arc functions to generate characters by assigning starting and end points. The bitmap method stores characters as arrays of pixels and allows for larger font sizes but produces aliased characters. The starburst method uses a fixed 24-bit line segment pattern to generate characters but requires more memory and produces lower quality characters with limited faces compared to the other methods.
![Program For Bitmap Method
• #include<stdio.h>
• #include<conio.h>
• #include<graphics.h>
• main()
• {
• int gd,gm,i,j;
int a[13][9] = {
• { 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},
• };
• /* Initialise graphics mode */
• detectgraph(&gd,&gm);
• initgraph(&gd,&gm,"c:tcbgi");
• Lecture 2 7
for(i=0;i<13;i++)
{
for(j=0;j<9;j++)
{
putpixel(200+j,200+i,15*a[i][j]);
}
}
getch();
closegraph();
}](https://image.slidesharecdn.com/charactergeneration-170418110622/85/Character-generation-7-320.jpg)
Character generation
- 1. AMITY UNIVERSITY, HARYANA COMPUTER GRAPHICS AnkIT GARG ASSISTAnT PROfESSOR AMITy UnIvERSITy, HARyAnA
- 2. 30/9/2008 Lecture 2 2 Character Generation Techniques Computer Graphics
- 3. 30/9/2008 Lecture 2 3 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
- 4. 30/9/2008 Lecture 2 4 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.
- 5. 30/9/2008 Lecture 2 5 Stoke method • The main disadvantage of this method is when we draw a diagonal line it produce aliased character.
- 6. 30/9/2008 Lecture 2 6 Bitmap Method
- 7. Program For Bitmap Method • #include<stdio.h> • #include<conio.h> • #include<graphics.h> • main() • { • int gd,gm,i,j; int a[13][9] = { • { 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}, • }; • /* Initialise graphics mode */ • detectgraph(&gd,&gm); • initgraph(&gd,&gm,"c:tcbgi"); • Lecture 2 7 for(i=0;i<13;i++) { for(j=0;j<9;j++) { putpixel(200+j,200+i,15*a[i][j]); } } getch(); closegraph(); }
- 8. 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. 30/9/2008 Lecture 2 8
- 9. 30/9/2008 Lecture 2 9 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.
- 10. 30/9/2008 Lecture 2 10 Starbust Method Disadvantages of starbust method 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. 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
- 11. 30/9/2008 Lecture 2 11 THANK YOU!!