c# - drawing shape following moving object -

what i'm trying connect webcam, detect colored object(blue patch), , need draw rectangle on form move object's move, many rectangles have been drawn each frame, need keep 1 rectangle moving blue object moving. how that?
alot.

it's bit hard understand doing without seeing code. i'll assume draw rectangle directly on form's graphics object, , webcam image not drawn on same form.

if so, should redraw whole area on form starts afresh between each frame.

if using paint event of form, try clearing canvas prior drawing rectangle:

private void form_paint(object sender, painteventargs e) {     e.graphics.clear(color.white);      // draw rectangle here. }