uses gdip

Screen 640,480,1
SetCaption "Spotlight"
SetSmoothMode 4

Function Distance(single x1,y1,x2,y2) as single
sys dx, dy
dx = x1-x2: dy = y1-y2
Return Sqr(dx*dx+dy*dy)
End Function

single max_distance, size
sys i, j
max_distance = distance 0,0,sWidth,sHeight

While Key(27)=0
ClsColor 55,255,255,255
For i=0 to sWidth step 20
  For j=0 to sHeight step 20
    size = Distance xMouse,yMouse,i,j
    size = size/max_distance*66
    FillOval i,j,size+10,size+10,ARGB 55,0,0,255
  Next
Next  
Flip
wend
Ends