Sure, reduce XMAX, YMAX but keep them proportional to the size paper printing on for proper preview.
CONST XMAX = 1100 / 1.3
CONST YMAX = 760 / 1.3
But all the pixel measures are not scaled so printout of font gets misaligned, my printout for January 2019 has "Wednesday" running into the right side of label box, in preview screen too with above screen size, XMAX for Width, YMAX for height.
(Wow the lines and letters are much thicker too.)
Eh, would require complete rework because pixel measures based on font size. All the line drawing remains proportional though.