linearbrush.js

var contextMargin = {top: 10, right: 40, bottom: 25, left: 60},
contextWidth = 440 - contextMargin.left - contextMargin.right,
contextHeight = 100 - contextMargin.top - contextMargin.bottom;

function linearBrush(layout, callbackObj) {
    this.layout;
    this.callbackObj = callbackObj;

    this.brushContainer = d3.select(layout.container)
	.append("svg")
	.attr("width", contextWidth + contextMargin.left + contextMargin.right)
	.attr("height", contextHeight + contextMargin.top + contextMargin.bottom)
	.attr("class", "contextTracks");

    this.x1 = d3.scale.linear()
	.range([0,contextWidth])
       	.domain([0, layout.genomesize]);

    this.mini = this.brushContainer.append("g")
	.attr("transform", "translate(" + contextMargin.left + "," + contextMargin.top + ")")
	.attr("width", contextWidth)
	.attr("height", contextHeight)
	.attr("class", "miniBrush");

    this.brush = d3.svg.brush()
	.x(this.x1)
	.on("brush", this.brushUpdate.bind(this));

    //    this.brush = brush;

    this.brushContainer = this.mini.append("g")
	.attr("class", "track brush")
	.call(this.brush.bind(this))
	.selectAll("rect")
	.attr("y", 1)
	.attr("height", contextHeight - 1);
 
    this.axisContainer = this.mini.append("g")
	.attr('class', 'brushAxis')
	.attr("transform", "translate(" + 0 + "," + contextHeight + ")");

    this.xAxis = d3.svg.axis().scale(this.x1).orient("bottom")
	.tickFormat(d3.format("s"));

    this.axisContainer.append("g")
    .attr("class", "context axis bottom")
    .attr("transform", "translate(0," + 0 + ")")
    .call(this.xAxis);

}

linearBrush.prototype.brushUpdate = function(b) {
    var minExtent = this.brush.extent()[0];
    var maxExtent = this.brush.extent()[1];

    if( Object.prototype.toString.call( this.callbackObj ) === '[object Array]' ) {
        for(var obj in this.callbackObj) {
            if(this.callbackObj.hasOwnProperty(obj)) {
                this.callbackObj[obj].update(minExtent, maxExtent);
            }
        }
    } else {
        this.callbackObj.update(minExtent, maxExtent);
    }

}

linearBrush.prototype.update = function(startBP, endBP) {

	this.brush.extent([startBP, endBP]);
	
	d3.selectAll('.brush').call(this.brush);

}

linearBrush.prototype.update_finished = function(startBP, endBP) {

}

linearBrush.prototype.addBrushCallback = function(obj) {

    // We allow multiple brushes to be associated with a linear plot, if we have
    // a brush already, add this new one on.  Otherwise just remember it.

    if('undefined' !== typeof this.callbackObj) {

	if( Object.prototype.toString.call( obj ) === '[object Array]' ) { 
	    this.callbackObj.push(obj);
	} else {
	    var tmpobj = this.callbackObj;
	    this.callbackObj = [tmpobj, obj];
	}
    } else {
	this.callbackObj = obj;
    }

}