[ новости /+++ | форум | теги | ]

NAME

pbm

 - portable bitmap file format

 

DESCRIPTION

• A "magic number" for identifying the file type. A pbm file's magic number is the two characters "P1".
• Whitespace (blanks, TABs, CRs, LFs).
• A width, formatted as ASCII characters in decimal.
• Whitespace.
• A height, again in ASCII decimal.
• Whitespace.
• Width * height bits, each either '1' or '0', starting at the top-left corner of the bitmap, proceeding in normal English reading order.
• The character '1' means black, '0' means white.
• Whitespace in the bits section is ignored.
• Characters from a "#" to the next end-of-line are ignored (comments).
• No line should be longer than 70 characters.

Here is an example of a small bitmap in this format:

P1
# feep.pbm
24 7
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 1 1 1 1 0 0 1 1 1 1 0 0 1 1 1 1 0 0 1 1 1 1 0
0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 1 0
0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 1 0
0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0
0 1 0 0 0 0 0 1 1 1 1 0 0 1 1 1 1 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Programs that read this format should be as lenient as possible, accepting anything that looks remotely like a bitmap.

There is also a variant on the format, available by setting the RAWBITS option at compile time. This variant is different in the following ways:

• The "magic number" is "P4" instead of "P1".
• The bits are stored eight per byte, high bit first low bit last.
• No whitespace is allowed in the bits section, and only a single character of whitespace (typically a newline) is allowed after the height.
• The files are eight times smaller and many times faster to read and write.

AUTHORS

Index

NAME

DESCRIPTION

AUTHORS

Партнёры:

Хостинг: