-void quant_transparent(i_quantize *quant, i_palidx *data, i_img *img,
+/*
+=item i_quant_transparent(quant, data, img, trans_index)
+
+=category Image quantization
+
+Dither the alpha channel on I<img> into the palette indexes in
+I<data>. Pixels to be transparent are replaced with I<trans_pixel>.
+
+The method used depends on the tr_* members of quant.
+
+=cut
+*/
+
+void
+i_quant_transparent(i_quantize *quant, i_palidx *data, i_img *img,