from jquant1.c:143
typedef struct
{
struct jpeg_color_quantizer pub;
JSAMPARRAY sv_colormap;
int sv_actual;
JSAMPARRAY colorindex;
boolean is_padded;
int Ncolors[MAX_Q_COMPS];
int row_index;
ODITHER_MATRIX_PTR odither[MAX_Q_COMPS];
FSERRPTR fserrors[MAX_Q_COMPS];
boolean on_odd_row;
} my_cquantizer;