Tony Cook > Imager > Imager::Preprocess



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Imager::Preprocess - simple preprocessor for handling multiple sample sizes


  /* in the source: */
  #code condition true to work with 8-bit samples
  ... code using preprocessor types/values ...

  # process and make #line directives
  perl -MImager::Preprocess -epreprocess foo.c

  # process and no #line directives
  perl -MImager::Preprocess -epreprocess -l foo.c


This is a simple preprocessor that aims to reduce duplication of source code when implementing an algorithm both for 8-bit samples and double samples in Imager.

Imager's Makefile.PL currently scans the MANIFEST for .im files and adds Makefile files to convert these to .c files.

The beginning of a sample-independent section of code is preceded by:

  #code expression

where expression should return true if processing should be done at 8-bits/sample.

You can also use a #code block around a function definition to produce 8-bit and double sample versions of a function. In this case #code has no expression and you will need to use IM_SUFFIX() to produce different function names.

The end of a sample-independent section of code is terminated by:


#code sections cannot be nested.

#/code without a starting #code is an error.

The following types and values are defined in a #code section:

Other types, functions and values may be added in the future.


Tony Cook <>

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