Fixed bug in panzoom with null canvas width or height.
Fixed bug in panzoom with null canvas width or height.

rossant/phy,rossant/phy,kwikteam/phy,nsteinme/phy,nippoo/phy,kwikteam/phy,kwikteam/phy,nsteinme/phy,nippoo/phy,rossant/phy