Sources Bitmap.

Sources Bitmap.

1 - The bitmap fonts are types of a certain size and with certain attributes or characteristics, such as bold or italic.
The bitmap is a record of a model of points required to create a certain character from a certain size, with
given attribute. The bitmaps Uppercase average of 36 points Times Roman family, the capital A bold 36
Family points Times Roman Uppercase and average 30 points Family Times.





2 - Most printers come with few bitmap fonts - usually Courier and Line Printer - with the attributes and normal Bold as part of the permanent memory (ROM). Furthermore, several printers have random access memory (RAM) for which the computer can send bitmaps from other sources. You can also add in the form of bitmap fonts cartridges used by several laser printers.



3 - When you give a print command - through the operating system or through the program - to a printer
using bitmap fonts, the first PC tells the printer which of the tables contained in the bitmap memory will be used.



4 - Then, for each letter, punctuation mark or paper movement - with a tab or carriage return - the
program want the printer to create the PC sends an ASCII code. ASCII codes consist of hexadecimal numbers sought in the table bitmaps. (The hexadecimal numbers are based on 16 - 0,1,2, 3,4,5,6,7,8,9 A, B, C, D, E, F - instead of used by the base 10 decimal numbers.) If, for example, is sent to the printer as hexadecimal 41 (decimal 65), processor printer seek the 41h in your table to find the model points that creates a capital of any type, source or attribute.

5 - The printer uses the bitmap to determine which instructions send to your other components so that they can reproduce the model of the bitmap on paper. The printer receives the computer character at a time.

Source: Evolution of Computers