//Both MulTable and DivTable are used in blend functions
MulTable[a,b] = a * b / 255

MulTable: array [Byte, Byte] of Byte;

//DivTable[a,b] = a * 255/b (for a <= b)

DivTable: array [Byte, Byte] of Byte;

//ScreenScale: is a measure of the primary screen's pixel density relative to a 'standard' 96 pixels per inch. Most modern screens - including desktop, tablet and phone screens - now have higher pixel densities than 96ppi. Nevertheless, understanding and accommodating varying screen scales is particularly important to avoid problems when images are scaled as this degrades image quality. (And this is particularly noticeable when rendering text.)

ScreenScale: double;