canvas level query number of objects in specified canvas (most useful with [gf/canvas_loadbang]) [doc_h] + [doc_c] + [doc_i] + [doc_f] + [doc_o] + [doc_cc] + [doc_ii] + [doc_oo] + 3 [doc_m] + 4 comments + floatbox + bangbox + [loadbang] + [gf/canvas_count] + [doc_also] + [gf/canvas_index] + [gf/canvas_loadbang] = 21