Question about outputting a matrix to a pgm file

Hello, I'm new to matlab and I've got a question about outputting matrix to a pgm file. I know the most direct way of doing this is using imwrite function, but I want to ask if there's any other method or code that could output the matrix to pgm file without using imwrite function, for example, using functions like fwrite? Please let me know if there's any idea.

Answer 1

[Walter Roberson]

Yes, the PGM file format is relatively simple. You can fopen(), fprintf() several times, and fclose()

https://netpbm.sourceforge.net/doc/pgm.html

It is not clear why you would want to do this yourself, but...

Note: if you are writing uint16 data, then the most significant byte must be first -- corresponding to fopen() with 'ieee-be' option.

[Botong Zhu]

So basically I just need to print all these necessary information(magic number, width, height etc) to the pgm file I desired using fprintf() and then it's done, if I didn't miss anything?

[Walter Roberson]

Yes, fprintf() the header values.

You probably need to fwrite() the data