make getDrawableDimensions() compatible to non-bitmaps (rel. to #11139)
make getDrawableDimensions() compatible to non-bitmaps (rel. to #11139)

tobiasge/cgeo,tobiasge/cgeo,rsudev/c-geo-opensource,cgeo/cgeo,rsudev/c-geo-opensource,cgeo/cgeo,cgeo/cgeo,rsudev/c-geo-opensource,cgeo/cgeo,tobiasge/cgeo