This test can be made against a value of zero if the inital value of scaledFraction has 2*dx subtracted from it. Giving, outside the loop:

	OffsetScaledFraction = dx + 2*dy - 2*dx = 2*dy - dx
	

and the inner loop becomes

	OffsetScaledFraction += 2*dy
	if (OffsetScaledFraction >= 0) {
	    y = y + 1;
	    fraction -= 2*dx;
	}

We might as well double the values of dy and dx (this can be accomplished with either an add or a shift outside the loop).