SVG未正确呈现作为骨干视图

Question

我正在使用d3.js在svg中渲染世界的地图（使用 https://github.com/johan/world.geo.json/blob/master/countries.geo.json 为特征）。我在骨干视图中封装了渲染逻辑。当我呈现视图并将其附加到DOM时，我的浏览器中的任何都没有显示，尽管在查看生成的HTML时正确生成SVG标记。当未在Backbone内封装时，此呈现很好。这是我使用backbone.view的代码：

/**
 * SVG Map view
 */
var MapView = Backbone.View.extend({
    tagName: 'svg',
    translationOffset: [480, 500],
    zoomLevel: 1000,

    /**
     * Sets up the map projector and svg path generator
     */
    initialize: function() {
        this.projector = d3.geo.mercator();
        this.path = d3.geo.path().projection(this.projector);
        this.projector.translate(this.translationOffset);
        this.projector.scale(this.zoomLevel);
    },

    /**
     * Renders the map using the supplied features collection
     */
    render: function() {
        d3.select(this.el)
          .selectAll('path')
          .data(this.options.featureCollection.features)
          .enter().append('path')
          .attr('d', this.path);
    },

    /**
     * Updates the zoom level
     */
    zoom: function(level) {
        this.projector.scale(this.zoomLevel = level);
    },

    /**
     * Updates the translation offset
     */
    pan: function(x, y) {
        this.projector.translate([
            this.translationOffset[0] += x,
            this.translationOffset[1] += y
        ]);
    },

    /**
     * Refreshes the map
     */
    refresh: function() {
        d3.select(this.el)
          .selectAll('path')
          .attr('d', this.path);
    }
});

var map = new MapView({featureCollection: countryFeatureCollection});
map.$el.appendTo('body');
map.render();

.

这是工作的代码，而无需使用backbone.view

var projector = d3.geo.mercator(),
    path = d3.geo.path().projection(projector),
    countries = d3.select('body').append('svg'),
    zoomLevel = 1000;

coords = [480, 500];
projector.translate(coords);
projector.scale(zoomLevel);

countries.selectAll('path')
         .data(countryFeatureCollection.features)
         .enter().append('path')
         .attr('d', path);

.

我还附上了生成的SVG标记的屏幕截图。任何想法在这里会出错吗？

编辑 - 这是每个请求的覆盖制作方法，最终解决了这个问题：

/**
 * Custom make method needed as backbone does not support creation of
 * namespaced HTML elements.
 */
make: function(tagName, attributes, content) {
    var el = document.createElementNS('http://www.w3.org/2000/svg', tagName);
    if (attributes) $(el).attr(attributes);
    if (content) $(el).html(content);
    return el;
}

.

Answer 1

The issue is that the "svg" element requires a namespace. D3 does this for your automatically; when you append an "svg" element, it uses the namespace "http://www.w3.org/2000/svg". For details, see src/core/ns.js. Backbone, unfortunately, does not appear to support namespaced elements. You'd want to change the view.make method. Then you'd need a namespaceURI property on your view to set the appropriate namespace, or just do it automatically for SVG elements for consistency with the HTML5 parser.

At any rate, a simple fix for your problem is to wrap your SVG in a DIV element, and then use D3 to create the SVG element.

Answer 2

You could simply set the view's element in the initialize function as follows:

Backbone.View.extend({
    // This is only for informaiton. The node will
    // be raplaced in the initialize function.
    tagName: 'svg',

    initialize: function () {
        this.setElement(
            d3.select($('<div/>')[0]).append('svg')[0]
        );
    }
);

This has the advantage of being explicite.

Answer 3

Check this out http://jsfiddle.net/nocircleno/QsEp2/ from http://nocircleno.com/blog/svg-with-backbone-js/

Backbone.View.extend({
  nameSpace: "http://www.w3.org/2000/svg",
  _ensureElement: function() {
     if (!this.el) {
        var attrs = _.extend({}, _.result(this, 'attributes'));
        if (this.id) attrs.id = _.result(this, 'id');
        if (this.className) attrs['class'] = _.result(this, 'className');
        var $el = $(window.document.createElementNS(_.result(this, 'nameSpace'), _.result(this, 'tagName'))).attr(attrs);
        this.setElement($el, false);
     } else {
        this.setElement(_.result(this, 'el'), false);
     }
 }
});