front_end/libs/Controls/Scale.js

//CLASS: 缩放控制类
function Scale(layer) {
    this.layer = layer;
    this.div = layer.div;
    this.active();
    this.mark=document.getElementById("mark");
    this.top="85px";
    this.top3d="85px";
};

Scale.prototype.wheelChange = function(e) {
	var type=e.type;
	var delta;
	if (type == 'DOMMouseScroll' || type == 'mousewheel') {
        delta = (e.wheelDelta) ? (e.wheelDelta / 120)*2 : -(e.detail || 0) / 3*2;
    }

	var deltalX = this.layer.size.w/2 - (e.offsetX || e.layerX);
    var deltalY = (e.offsetY || e.layerY) - this.layer.size.h/2;
    
    var px = {x: (e.offsetX || e.layerX), y:(e.offsetY || e.layerY)};
    var zoomPoint = this.layer.getPositionFromPx(px);    
    var zoom = this.layer.zoom + delta;
    if(zoom <= 16) {
        return;
    }
    
   
    var markpy=parseInt(this.mark.style.marginTop);
    markpy-=delta;
    if(markpy<MixMark)
    {
    	markpy=MixMark;
    }
    else if(markpy>MaxMark)
    {
    	markpy=MaxMark;
    }
    mark.style.marginTop=markpy+"px";
    this.top=mark.style.marginTop;
    
    var newRes = this.layer.getResFromZoom(zoom);
    
    var center = new CanvasSketch.Position(zoomPoint.x + deltalX * newRes, zoomPoint.y + deltalY * newRes);
    
    this.layer.moveTo(zoom, center);
	this.layer.renderer.autoRedraw();
    CanvasSketch.stopEventBubble(e);
};

Scale.prototype.DOMScroll = function(e) {
    CanvasSketch.stopEventBubble(e);
};

Scale.prototype.Events = [["mousewheel", Scale.prototype.wheelChange],["DOMMouseScroll", Scale.prototype.wheelChange]];

Scale.prototype.active = function () {
	this.div.addEventListener("mousewheel", Scale.prototype.wheelChange.bind(this), true);      
	this.div.addEventListener("DOMMouseScroll", Scale.prototype.wheelChange.bind(this), true);    
};