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diff --git a/libglitter.7 b/libglitter.7 new file mode 100644 index 0000000..a446eeb --- /dev/null +++ b/libglitter.7 @@ -0,0 +1,89 @@ +.TH LIBGLITTER 7 LIBGLITTER +.SH NAME +libglitter - Subpixel-rendering library +.SH DESCRIPTION +.B libglitter +is a C library for subpixel-rendered text from an +greyscale-antialiased text image. +.B libglitter +is designed to be +used in conjunction with other font libraries: it can neither +rasterise glyphs nor does it know about the montor's subpixel +layout or rendering configurations. +.PP +To use +.B libglitter +you first apply hinting to the text so that +the glyph outlines aligns with the output's pixel-grid as +closely as possible. The next step is to get the output's +subpixel arrangement and scaling factor, then assuming that +the output's subpixel arrangement is subpixel-rendering +compatible and that its native resolution is used, you +rasterise the text using greyscale-antialiasing into a raster +sized according to the output's horizontal and vertical +subpixel densities (rather than pixel densities as normally +done with greyscale-antialiasing; some subpixels may have be +counted multiple times depending on the subpixel arrangement). +After this you create an uninitialised colour raster for text +and the output's pixel density, and split it into one raster +per colour channel using +.BR libglitter_split_uint64_raster (3) +or +.BR libglitter_split_uint32_raster (3), +this is when +.B libglitter +is first used in this process; alternatively you create one +raster for each colour channel directly. Then you use +.BR libglitter_compose_double (3), +.BR libglitter_compose_float (3), +.BR libglitter_compose_uint64 (3), +.BR libglitter_compose_uint32 (3), +.BR libglitter_compose_uint16 (3), +or +.BR libglitter_compose_uint8 (3) +to create the subpixel-antialiased image of the text; you may +have to first call +.BR libglitter_reorder_rasters (3) +to put the rasters in the expected order. +.PP +An optional next step is to use lessen the intensity of the +subpixel-antialiasing with +.BR libglitter_desaturate_double (3), +.BR libglitter_desaturate_float (3), +.BR libglitter_per_channel_desaturate_double (3), +or +.BR libglitter_per_channel_desaturate_float (3). +.PP +Then, if the application cannot output directly to the +output's colour model, the application can use +.BR libglitter_get_colour_model_conversion_matrix_double (3) +and +.BR libglitter_colour_model_convert_rasters_double (3) +or +.BR libglitter_get_colour_model_conversion_matrix_float (3) +and +.BR libglitter_colour_model_convert_rasters_float (3) +to convert a colour model the application can output in. It is +however out of the scope of +.B libglitter +to get the output's +colour model and the conversion matrix to any other colour +model than sRGB or CIE XYZ. +.PP +The finally step of the rendering process is out of scope for +.BR libglitter , +but is to ensure that all floating-point values +(if floating-point rasters are used) are withing [0, 1] and +convert the rasters, which only contain ink-on intensities, +into the desired colour's with the output's transfer function +applied. +.PP +The application may also desire to call +.BR libglitter_enable_acceleration (3) +at the beginning of its execution to enable +any implemented and supported hardware acceleration. This +may however be an expensive process, and may not be +desirable for all applications. +.PP +.SH SEE ALSO +.BR libfonts (7) |