If you draw line with one point is outside the screen, pocketfrog may draw it for different direction
try this:
int x1=226;
int y1=57;
int x2=253;
int y2=-94;
display->DrawLine(x1,y1,x2,y2,Color(0,0,0));
pocketfrog draw the wrong line. it looks likely this is related to x2,y2 are out of screen.
but for points below, x2,y2 are out of screen also, pocketfrog can draw the correct line:
x1= 237; y1= 59
x2= 332; y2= -79
why?