NAME libglitter - Subpixel-rendering library DESCRIPTION libglitter is a C library for subpixel-rendered text from an greyscale-antialiased text image. 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. To use libglitter you first need to output's pixel density, then you apply hinting to the text you want to render using this information. The next step is to get the output's subpixel arrangement and scaling factor, then assuming that the output's subpixel arrangement i subpixel-rendering compatible and that the native resolution is used, you multiply the output's DPI:s so that you get the number of subpixels per inch instead of number of pixels per inch (some subpixels may have be counted multiple times depending on the subpixel arrangement) and you create a greyscale raster of the text for these new DPIs. 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 libglitter_split_uint64_raster(3) or libglitter_split_uint32_raster(3), alternatively you create one raster for each colour channel directly. Then you use libglitter_compose_double(3), libglitter_compose_float(3), libglitter_compose_uint64(3), libglitter_compose_uint32(3), libglitter_compose_uint16(3), or libglitter_compose_uint8(3) to create the subpixel-antialiased image of the text; you may have to first call libglitter_reorder_rasters(3) to put the rasters in the expected order. An optional next step is to use lessen the intensity of the subpixel-antialiasing with libglitter_desaturate_double(3), libglitter_desaturate_float(3), libglitter_per_channel_- desaturate_double(3), or libglitter_per_channel_desaturate_- float(3). Then, if the application cannot output directly to the output's colour space, the application can use libglitter_get_colour_space_conversion_matrix_double(3) and libglitter_colour_space_convert_rasters_double(3) or libglitter_get_colour_space_conversion_matrix_float(3) and libglitter_colour_space_convert_rasters_float(3) to convert a colour space the application can output in. It is however out of the scope of libglitter to get the output's colour space and the conversion matrix to any other colour space than sRGB or CIE XYZ. The finally step of the rendering process is out of scope for 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. The application may also desire to call 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. SEE ALSO libfonts(7)