I need a "slider" in a circle

[Colin Holgate]

Here is a version that would work for a complete circle:

global cw,ch,cx,cy,offx,offy

on mousedown
   put the width of graphic "circle" / 2 into cw
   put the height of graphic "circle" / 2 into ch
   put the left of graphic "circle" + cw into cx
   put the top of graphic "circle" + ch into cy
   put the width of me / 2 into offx
   put the height of me / 2 into offy
   moveme
end mousedown

on moveme
   local dx,dy,ang
   put the mouseh - cx into dx
   put the mousev - cy  into dy
   put atan2(dy,dx) into ang
   set the left of me to cos(ang) * cw - offx + cx
   set the top of me to sin(ang) * ch - offy + cy
   if the mouse is down then send moveme to me in 3 ticks
end moveme