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.TH LIBGLITTER_COLOUR_MODEL_CONVERT_RASTERS_* 3 LIBGLITTER
.SH NAME
LIBGLITTER_COLOUR_MODEL_CONVERT_RASTERS_* - Change colour model used for a set of corasters
.SH SYNOPSIS
.LP
.nf
#include <libglitter.h>
void libglitter_colour_model_convert_rasters_double(size_t \fIn\fP, size_t \fIm\fP, double *\fIoutputs\fP[m],
const double *\fIinputs\fP[n], size_t \fIoutput_rowsize\fP,
size_t \fIoutput_cellsize\fP, size_t \fIinput_rowsize\fP,
size_t \fIinput_cellsize\fP, size_t \fIwidth\fP,
size_t \fIheight\fP, const double \fImatrix\fP[m][n]);
void libglitter_colour_model_convert_rasters_float(size_t \fIn\fP, size_t \fIm\fP, float *\fIoutputs\fP[m],
const float *\fIinputs\fP[n], size_t \fIoutput_rowsize\fP,
size_t \fIoutput_cellsize\fP, size_t \fIinput_rowsize\fP,
size_t \fIinput_cellsize\fP, size_t \fIwidth\fP,
size_t \fIheight\fP, const float \fImatrix\fP[m][n]);
.fi
.PP
Link with
.IR "-lglitter -lm" .
.SH DESCRIPTION
The
.BR libglitter_colour_model_convert_rasters_double ()
and
.BR libglitter_colour_model_convert_rasters_float ()
functions convert a set of rasters (one per source
colour channel) into another set of rasters (one per
target colour channel) using a different colour model.
This is useful for application that cannot output
directly in the output's colour model.
.PP
.I n
shall be the number of source colour channels
(input rasters), and
.I m
shall be the number of target colour channels
(output rasters).
.PP
.I outputs
shall be the list of output rasters: it is to its elements
that the function will write. Note that the rasters shall
already be allocated. Additionally, the function may offset
the input pointers in this list during execution. Therefore,
the contents of this list shall be considered undefined
immediately when the function is called, and may not be
modified before the function terminates. The application
must therefore have the pointers to these rasters saved
elsewhere. The order the rasters shall have in the list
.I outputs
is determined how the colour model conversion matrix
.RI ( matrix )
was constructed: if it was created using the
.BR libglitter_colour_model_convert_rasters_double (3),
function, or the
.BR libglitter_colour_model_convert_rasters_float (3),
function, the order shall be (0) red, (1) green, (2) blue
or (0) X, (1) Y, (2) Z.
.PP
.I inputs
shall be the list of input rasters: it is from its elements
that the function will read. The function may offset the
input pointers in this list during execution. Therefore,
the contents of this list shall be considered undefined
immediately when the function is called, and may not be
modified before the function terminates. The application
must therefore have the pointers to these rasters saved
elsewhere. The order the rasters shall have in the list
.I inputs
is determined how the colour model conversion matrix
.RI ( matrix )
was constructed: if it was created using the
.BR libglitter_colour_model_convert_rasters_double (3),
function, or the
.BR libglitter_colour_model_convert_rasters_float (3),
function, the order shall the order the output's primary
colours' chromas hade in the function's argument list.
.PP
.I output_cellsize
shall be the number of elements in an output raster the
pointer to the raster must be offset with to get to a
pointer to the next cell in the raster.
.PP
.I output_rowsize
shall be the number of cells (not elements; but rather the
number of elements divided by
.IR output_cellsize )
in an output raster the pointer to the raster must be
offset with to get a pointer to the next row but the
same column in the raster
.PP
.I input_cellsize
shall be the number of elements in an input raster the
pointer to the raster must be offset with to get to a
pointer to the next cell in the raster.
.PP
.I input_rowsize
shall be the number of cells (not elements; but rather the
number of elements divided by
.IR input_cellsize )
in an input raster the pointer to the raster must be
offset with to get a pointer to the next row but the
same column in the raster
.PP
.I width
and
.I height
shall describe the affected area in the rasters.
.I width
shall be the number of pixels the rasters have
horizontally, and
.I height
shall be the number of pixels the rasters have
vertically.
.PP
.I matrix
shall be column-major conversion matrix from the source
colour model (the output's colour model) to the target
colour model (the application's colour model).
.PP
All rasters are in row-major order and must be distinct,
except the input rasters are allowed to the same, with
the same offsets, as the output rasters: they must overlap
exactly or not at all.
.PP
By default, these functions do not use hardware acceleration,
they run on the CPU. However the
.BR libglitter_enable_acceleration (3)
may be able to enable hardware acceleration for these
functions. It will require at least the following bits in
its first argument to enable hardware acceleration:
.RS
.TP
.I LIBGLITTER_FEATURE_COLOUR_MODEL | LIBGLITTER_FEATURE_DOUBLE_TYPE
for
.BR libglitter_colour_model_convert_rasters_double ()
or
.TP
.I LIBGLITTER_FEATURE_COLOUR_MODEL | LIBGLITTER_FEATURE_FLOAT_TYPE
for
.BR libglitter_colour_model_convert_rasters_float ().
.RE
.SH RETURN VALUES
None.
.SH ERRORS
None.
.SH SEE ALSO
.BR libglitter (7),
.BR libglitter_colour_model_convert_rasters_double (3),
.BR libglitter_compose_double (3),
.BR libglitter_desaturate_double (3)
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