Flash AS2 map scaling implementation code

The code is as follows:

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Stop (); Var DefaultX = 0; Var DefaultY = 0; Var DefaultValue = true; Var _ C = mapMC. Content; _ C. _ alpha = 0; _ RW = Stage. width; _ RH = Stage. height; _ MW = mapMC. _ width; _ MH = mapMC. _ height; Var coordinate: XML = new XML (); Coordinate. ignoreWhite = true; Coordinate. load ("coordinate. xml "); Coordinate. onLoad = function (success) { List = coordinate. childNodes [0]. childNodes; For (g = 0; g <list. length; g ++)     { Var t = mapMC. attachMovie ("arrow", "a" + g, g + 1 ); T. angle = g * (Math. PI * 2)/numofbils ); T. _ x = (list [g]. attributes. x-(t. _ width-30) * 4; T. _ y = (list [g]. attributes. y-(t. _ height-7) * 4; T. swapDepths (-g ); ContentShow (g );     } }; Function ContentShow (num) { Var Vlist = coordinate. childNodes [0]. childNodes [num]; MapMC ["a" + num]. Onrolover = function ()     { This. gotoAndPlay (2 ); This. swapDepths (1 ); This. _ y = this. _ y-4; New mx. transitions. Tween (_ C, "_ alpha", mx. transitions. easing. Regular. easeOut, 0,100,. 5, true ); _ C. _ x = this. _ x; _ C. _ y = this. _ y-120; _ C. _ Info. text = Vlist. attributes. alt; }; MapMC ["a" + num]. Onrolout = function ()     { This. gotoAndPlay (1 ); This. swapDepths (-g ); This. _ y = this. _ y + 4; New mx. transitions. Tween (_ C, "_ alpha", mx. transitions. easing. Regular. easeOut, 100, 0,. 5, true ); }; } MapMC. onMouseDown = function () { This. startDrag (false, 0, _ RH-_ MW,-_ MW + _ RW, 0, _ RW ); // Calculate the position of the current MC in the center of the canvas. DefaultX = this. _ x + (_ RW/2 ); DefaultY = this. _ y + (_ RH/2 ); }; MapMC. onMouseUp = function () { StopDrag (); }; Var myListener: Object = new Object (); MyListener. onMouseWheel = function (delta) { With (mapMC ){ Var omx = _ xmouse, omy = _ ymouse; _ Xscale + = delta; _ Yscale + = delta; _ X-= omx x * delta/100; _ Y-= omy * delta/100;         } _ MW = mapMC. _ width; _ MH = mapMC. _ height; }; Mouse. addListener (myListener );

The center point of the current MC is obtained, namely: DefaultX and DefaultY. However, the logic is hard to figure out how to arrange the current MC with the central point.
Code snippet:

The code is as follows:	Copy code
DefaultX = this. _ x + (_ RW/2 ); DefaultY = this. _ y + (_ RH/2 );

In the end, the zoom-in and zoom-out of the map is aimed at the overall size and center of the MC, which is ineffective.
Code snippet:

The code is as follows:	Copy code
MapMC. _ x =-(mapMC. _ width/2) + (_ RW/2 ); MapMC. _ y =-(mapMC. _ height/2) + (_ RH/2 );

Because the map is much larger than the canvas, the user experience is poor if you do not scale the mouse position.
I would like to ask you to pass. How does AS2 scale the mouse over MC and increase the buffer effect?

Download instance

First part of http://www.111cn.net/down/MapFla.part1.rar
Http://www.111cn.net/down/MapFla.part2.rar part 2