+/*
+=item i_quantize
+=category Data Types
+
+A structure type used to supply image quantization, ie. when
+converting a direct color image to a paletted image.
+
+This has the following members:
+
+=over
+
+=item *
+
+C<transp> - how to handle transparency, see L</i_transp>.
+
+=item *
+
+C<threshold> - when C<transp> is C<tr_threshold>, this is the alpha
+level at which pixels become transparent.
+
+=item *
+
+C<tr_errdiff> - when C<transp> is C<tr_errdiff> this controls the type
+of error diffusion to be done. This may not be C<ed_custom> for this
+member.
+
+=item *
+
+C<tr_orddith> - when C<transp> is C<tr_ordered> this controls the
+patten used for dithering transparency.
+
+=item *
+
+C<tr_custom> - when C<tr_orddith> is C<tr_custom> this is the ordered
+dither mask.
+
+=item *
+
+C<make_colors> - the method used to generate the color palette, see
+L</i_make_colors>.
+
+=item *
+
+C<mc_colors> - an array of C<mc_size> L</i_color> entries used to
+define the fixed colors (controlled by C<mc_count> and to return the
+generated color list.
+
+=item *
+
+C<mc_size> - the size of the buffer allocated to C<mc_colors> in
+C<sizeof(i_color)> units.
+
+=item *
+
+C<mc_count> - the number of initialized colors in C<mc_colors>.
+
+=item *
+
+C<translate> - how RGB colors are translated to palette indexes, see
+L</i_translate>.
+
+=item *
+
+C<errdiff> - when C<translate> is C<pt_errdiff> this controls the type
+of error diffusion to be done.
+
+=item *
+
+C<ed_map>, C<ed_width>, C<ed_height>, C<ed_orig> - when C<errdiff> is
+C<ed_custom> this controls the error diffusion map. C<ed_map> is an
+array of C<ed_width * ed_height> integers. C<ed_orig> is the position
+of the current pixel in the error diffusion map, always on the top
+row.
+
+=item *
+
+C<perturb> - the amount to perturb pixels when C<translate> is
+C<mc_perturb>.
+
+=back
+
+=cut
+*/