fix "r" command when no canvas specified, cleanups
fix "r" command when no canvas specified, cleanups

superjudge/openvg,chappyhome/openvg,mayqueenRD/OpenVG_Rasbian_UI,superjudge/openvg,superjudge/openvg,mayqueenRD/OpenVG_Rasbian_UI,chappyhome/openvg,chappyhome/openvg,chappyhome/openvg,superjudge/openvg,mayqueenRD/OpenVG_Rasbian_UI