ExploreGraphics with maintaining AspectRatio

ExploreGraphics.txt

ExploreGraphics::usage = 
  "Pass a Graphics object to explore it by zooming and panning with   \
 left and right mouse buttons respectively. Left click once to reset  \
  view.";
OptAxesRedraw::usage = 
  "Option for ExploreGraphics to specify redrawing of axes. Default   \
 True.";
Options[ExploreGraphics] = {OptAxesRedraw -> True};

ExploreGraphics[graph_Graphics, opts : OptionsPattern[]] := 
  With[{gr = First[graph], 
    opt = DeleteCases[Options[graph], 
      PlotRange -> _ | AspectRatio -> _ | AxesOrigin -> _], 
    plr = PlotRange /. AbsoluteOptions[graph, PlotRange], 
    ar = AspectRatio /. AbsoluteOptions[graph, AspectRatio], 
    ao = AbsoluteOptions[AxesOrigin], 
    rectangle = {Dashing[Small], 
       Line[{#1, {First[#2], Last[#1]}, #2, {First[#1], 
          Last[#2]}, #1}]} &, 
    optAxesRedraw = OptionValue[OptAxesRedraw]}, 
   DynamicModule[{dragging = False, first, second, boxSize, minPos, 
     rx1, rx2, ry1, ry2, range = plr}, {{rx1, rx2}, {ry1, ry2}} = 
     plr;
    Panel@
     EventHandler[
      Dynamic@Graphics[
        If[dragging, {gr, rectangle[first, second]}, gr], 
        PlotRange -> Dynamic@range, AspectRatio -> ar, 
        AxesOrigin -> 
         If[optAxesRedraw, Dynamic@Mean[range\[Transpose]], ao], 
        Sequence @@ opt], {{"MouseDown", 
         1} :> (first = MousePosition["Graphics"]), {"MouseDragged", 
         1} :> (dragging = True;
         boxSize = MousePosition["Graphics"] - first;
         minPos = Min[Abs[boxSize]];
         second = 
          first + {minPos, minPos}*RealSign[boxSize]), {"MouseUp", 
         1} :> If[dragging, dragging = False;
         range = {{rx1, rx2}, {ry1, ry2}} = Transpose@{first, second},
          range = {{rx1, rx2}, {ry1, ry2}} = plr], {"MouseDown", 
         2} :> (first = {sx1, sy1} = 
           MousePosition["Graphics"]), {"MouseDragged", 
         2} :> (second = {sx2, sy2} = MousePosition["Graphics"];
         rx1 = rx1 - (sx2 - sx1);
         rx2 = rx2 - (sx2 - sx1);
         ry1 = ry1 - (sy2 - sy1);
         ry2 = ry2 - (sy2 - sy1);
         range = {{rx1, rx2}, {ry1, ry2}})}]]];