Use this function to invert a graphical area. The syntax is a follows:

%LCD.Gfx_SetInvertArea(x1,y1,x2,y2)

x1,y1 = upper left point of invert area rectangle
x2,y2 = lower right point of invert area rectangle

Example:

%LCD.Gfx_SetInvertArea(10,10,100,20)

This function inverts a area from x-position 10px to 100px and y-position 10px to 20px.