It would be nice to add ellipse capability. (Draw & Fill) It would be better to fold/merge this in with the circle and rounded rectangle code rather than a single separate routine. Code for it is below. It does work:

void Plot4EllipsePoints(long CX,long CY, long X, long Y, uint8_t color){ GLCD.SetDot(CX+X, CY+Y, color); //{point in quadrant 1} GLCD.SetDot(CX-X, CY+Y, color); //{point in quadrant 2} GLCD.SetDot(CX-X, CY-Y, color); //{point in quadrant 3} GLCD.SetDot(CX+X, CY-Y, color); //{point in quadrant 4}

ifdef TOFILL

// to fill rather than draw a line, plot between the points GLCD.DrawLine(CX+X, CY+Y, CX-X, CY+Y, color); GLCD.DrawLine(CX-X, CY-Y, CX+X, CY-Y, color);

endif

}

void glcd::DrawEllipse(long CX, long CY, long XRadius,long YRadius, uint8_t color) { // portted the algorithm found at // http://homepage.smc.edu/kennedy_john/belipse.pdf // by John Kennedy

long X, Y; long XChange, YChange; long EllipseError; long TwoASquare,TwoBSquare; long StoppingX, StoppingY; TwoASquare = 2*XRadius*XRadius; TwoBSquare = 2*YRadius*YRadius; X = XRadius; Y = 0; XChange = YRadius*YRadius*(1-2*XRadius); YChange = XRadius*XRadius; EllipseError = 0; StoppingX = TwoBSquare*XRadius; StoppingY = 0;

while ( StoppingX >=StoppingY ) //first set of points,y'>-1 { Plot4EllipsePoints(CX,CY,X,Y,color); Y++; StoppingY=StoppingY+ TwoASquare; EllipseError = EllipseError+ YChange; YChange=YChange+TwoASquare; if ((2*EllipseError + XChange) > 0 ) { X--; StoppingX=StoppingX- TwoBSquare; EllipseError=EllipseError+ XChange; XChange=XChange+TwoBSquare; } } //{ first point set is done; start the 2nd set of points }

Y = YRadius; X = 0; YChange = XRadius*XRadius*(1-2*YRadius); XChange = YRadius*YRadius; EllipseError = 0; StoppingY = TwoASquare*YRadius; StoppingX = 0; while ( StoppingY >=StoppingX ) //{2nd set of points, y'< -1} { Plot4EllipsePoints(CX,CY,X,Y,color); X++; StoppingX=StoppingX + TwoBSquare; EllipseError=EllipseError+ XChange; XChange=XChange+TwoBSquare; if ((2*EllipseError + YChange) > 0 ) { Y--; StoppingY=StoppingY- TwoASquare; EllipseError=EllipseError+ YChange; YChange=YChange+TwoASquare; } } }; //{procedure PlotEllipse}