C:\Perl_PPM\Imager-1.002\blib/lib/Imager/Preprocess.pm |
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 ... #/code
# process and make #line directives perl -MImager::Preprocess -epreprocess foo.im foo.c
# process and no #line directives perl -MImager::Preprocess -epreprocess -l foo.im 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
#code sections cannot be nested.
#/code without a starting #code is an error.
The following types and values are defined in a #code section:
im
, x
, y
, &col
)
IM_GLIN(im
, l
, r
, y
, colors
)
IM_PPIX(im
, x
, y
, &col
)
IM_PLIN(im
, x
, y
, colors
)
IM_GSAMP(im
, l
, r
, y
, samples
, chans
, chan_count
)
These correspond to the appropriate image function, eg. IM_GPIX()
becomes i_gpix()
or i_gpixf()
as appropriate.
dest_channels
, src_channels
, colors
, count
)
Call i_adapt_colors()
or i_adapt_fcolors().
fill
) - retrieve the combine function from a fill
object.
IM_FILL_FILLER(fill
) - retrieve the fill_with_* function from a fill
object.
IM_SAMPLE_MAX - maximum value for a sample
IM_SAMPLE_MAX2 - maximum value for a sample, squared
IM_SAMPLE_T - type of a sample (i_sample_t or i_fsample_t)
IM_COLOR - color type, either i_color or i_fcolor.
IM_WORK_T - working sample type, either int or double.
IM_Sf - format string for the sample type, "%d"
or "%f"
.
IM_Wf - format string for the work type, "%d"
or "%f"
.
IM_SUFFIX(identifier)
- adds _8 or _double onto the end of identifier.
IM_EIGHT_BIT - this is a macro defined only in 8-bit/sample code.
Other types, functions and values may be added in the future.
Tony Cook <tonyc@cpan.org>
C:\Perl_PPM\Imager-1.002\blib/lib/Imager/Preprocess.pm |