this code
GLCD.DrawCircle(31,31,31,BLACK);
GLCD.DrawLine(31,31,31,0);
creates a vertical line not a horizontal
so it is GLCD.DrawLine(X0,Y0,Y1,X1);
this code
GLCD.DrawCircle(31,31,31,BLACK);
GLCD.DrawLine(31,31,31,0);
creates a vertical line not a horizontal
so it is GLCD.DrawLine(X0,Y0,Y1,X1);