LqrColDepth — carver objects colour depth specification
                        The default LqrCarver object constructor lqr_carver_new uses a colour
                        depth of 8 bits per channel, and therefore its input must be an array of unsigned
                        chars. However, the LqrCarver objects can handle images of grater colour depth, if
                        they are created with the lqr_carver_new_ext constructor. The possible
                        colour depths are specified through variables of type LqrColDepth, which is an enum
                        type; its possible values, and the type of the input buffer associated with them, are:
                        
LQR_COLDEPTH_8Iuse type guchar (8 bit unsigned integers) - the default
LQR_COLDEPTH_16Iuse type guint16 (16 bit unsigned integers)
LQR_COLDEPTH_32Fuse type gfloat (32 bit floating point)
LQR_COLDEPTH_64Fuse type gdouble (64 bit floating point)
                        These values are also relevant when reading out a LqrCarver object with the functions
                        lqr_carver_scan_ext or lqr_carver_scan_line_ext, since
                        the readout buffer must be cast to the appropriate type to be actually read. 
                    
                        The colour depth of an LqrCarver object can be obtained with the function
                        lqr_carver_get_col_depth.