construct defer buffer imag us gef render current diagram demand param draw area bound rectangl area drawn param imag type type imag creat type argb imag type support buffer imag param ed gef editor us render imag param scale factor integ scale factor multipli render imag defer buffer imag rectangl draw area imag type editor ed scale factor editor ed scale scale factor draw area draw area width draw area width height draw area height scale scale scale width width scale height height scale scale buffer height buffer height scale creat bandbuff just small slice imag todo us fix height buffer smarter comput height fit memori budget allow us taller buffer narrow imag minim overhead multipl render pass imag buffer imag width scale buffer height imag type initi band buffer bound 