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diff --git a/libglitter_desaturate_double.3 b/libglitter_desaturate_double.3 new file mode 100644 index 0000000..057efb7 --- /dev/null +++ b/libglitter_desaturate_double.3 @@ -0,0 +1,141 @@ +.TH LIBGLITTER_*DESATURATE_* 3 LIBGLITTER +.SH NAME +libglitter_*desature_* - Create a blend between subpixel- and greyscale-antialiasing +.SH SYNOPSIS +.LP +.nf +#include <libglitter.h> + +void libglitter_desaturate_double(double **\fIrasters\fP, size_t \fInrasters\fP, + size_t \fIrowsize\fP, size_t \fIcellsize\fP, + size_t \fIwidth\fP, size_t \fIheight\fP, + double \fIsaturation\fP, + const double *\fIprimary_ys\fP); + +void libglitter_desaturate_float(float **\fIrasters\fP, size_t \fInrasters\fP, + size_t \fIrowsize\fP, size_t \fIcellsize\fP, + size_t \fIwidth\fP, size_t \fIheight\fP, + float \fIsaturation\fP, + const float *\fIprimary_ys\fP); + +void libglitter_per_channel_desaturate_double(double **\fIrasters\fP, size_t \fInrasters\fP, + size_t \fIrowsize\fP, size_t \fIcellsize\fP, + size_t \fIwidth\fP, size_t \fIheight\fP, + const double \fIsaturations\fP, + const double *\fIprimary_ys\fP); + +void libglitter_per_channel_desaturate_float(float **\fIrasters\fP, size_t \fInrasters\fP, + size_t \fIrowsize\fP, size_t \fIcellsize\fP, + size_t \fIwidth\fP, size_t \fIheight\fP, + const float \fIsaturations\fP, + const float *\fIprimary_ys\fP); +.fi +.PP +Link with +.IR "-lglitter -lm" . +.SH DESCRIPTION +The +.BR libglitter_desaturate_double (), +.BR libglitter_desaturate_float (), +.BR libglitter_per_channel_desaturate_double (), +and +.BR libglitter_per_channel_desaturate_float (), +functions desaturates a set of corasters (makes them more grey). +.PP +.I rasters +shall be the list of rasters, which are modified in place. +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. +.PP +The number of rasters shall be specified as the +.I nrasters +argument. +.PP +.I cellsize +shall be the number of elements in a raster the pointer +to the raster must be offset with to get to a pointer to +the next cell in the raster. +.PP +.I rowsize +shall be the number of cells (not elements; but rather the +number of elements divided by +.IR input_cellsize ) +in a 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 +For the +.BR libglitter_desaturate_double () +and +.BR libglitter_desaturate_float () +functions, the +.I saturation +argument shall be how saturated the subpixel-antialiasing shall +be, where 0 renders greyscale-antialiasing and 1 renders regular +subpixel-antialiasing. For the +.BR libglitter_per_channel_desaturate_double () +and +.BR libglitter_per_channel_desaturate_float () +functions this parameter is replaced with the +.I saturations +parameter which shall be a list of one saturation value per +raster: these functions let the user desaturate each channel +by a different amount. +.PP +Each primary colour's CIE Y value shall be provided via the +.I primary_ys +parameter. If you only have the output's primary colours' +chroma as CIE xy values, and the output's white point, the +.BR libglitter_get_colour_model_conversion_matrix_double (3) +and +.BR libglitter_get_colour_model_conversion_matrix_float (3) +can calculate and output the primary colour's CIE Y values. +.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_CU_DESATURATION | LIBGLITTER_FEATURE_DOUBLE_TYPE +for +.BR libglitter_desaturate_double (), +.TP +.I LIBGLITTER_FEATURE_CU_DESATURATION | LIBGLITTER_FEATURE_FLOAT_TYPE +for +.BR libglitter_desaturate_float (), +.TP +.I LIBGLITTER_FEATURE_PC_DESATURATION | LIBGLITTER_FEATURE_DOUBLE_TYPE +for +.BR libglitter_per_channel_desaturate_double (), +or +.TP +.I LIBGLITTER_FEATURE_PC_DESATURATION | LIBGLITTER_FEATURE_FLOAT_TYPE +for +.BR libglitter_per_channel_desaturate_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) |