r Quad To
Adds quad from last point towards vector (dx1, dy1), to vector (dx2, dy2). If Path is empty, or last PathVerb is PathVerb.CLOSE, last point is set to (0, 0) before adding quad.
Appends PathVerb.MOVE to verb array and (0, 0) to Point array, if needed; then appends PathVerb.QUAD to verb array; and appends quad control and quad end to Point array.
Quad control is last point plus vector (dx1, dy1).
Quad end is last point plus vector (dx2, dy2).
Function name stands for "relative quad to".
Return
reference to Path
Parameters
dx1
offset from last point to quad control on x-axis
dy1
offset from last point to quad control on y-axis
dx2
offset from last point to quad end on x-axis
dy2
offset from last point to quad end on y-axis