使用Joint JS在SVG中创建了一个文本区域。但是，我无法在文本区域中输入任何文本。如何使文本区域可编辑？
代码：
var graph = new joint.dia.Graph;
var paper = new joint.dia.Paper({
el: $('#myholder'),
width: 1500,
height: 700,
model: graph
});
// Create a custom element.
// ------------------------
joint.shapes.html = {};
joint.shapes.html.Element = joint.shapes.basic.Generic.extend(_.extend({}, joint.shapes.basic.PortsModelInterface, {
markup: '<g class="rotatable"><g class="scalable"><rect/></g><g class="inPorts"/><g class="outPorts"/></g>',
portMarkup: '<g class="port<%=1%>"><circle/></g>',
defaults: joint.util.deepSupplement({
type: 'html.Element',
size: {width: 100, height: 80},
inPorts: [],
outPorts: [],
attrs: {
'.': {magnet: false},
rect: {
stroke: 'none', 'fill-opacity': 0, width: 150, height: 250,
},
circle: {
r: 6, //circle radius
magnet: true,
stroke: 'black'
},
'.inPorts circle': {fill: 'green', magnet: 'passive', type: 'input'},
'.outPorts circle': {fill: 'red', type: 'output'}
}
}, joint.shapes.basic.Generic.prototype.defaults),
getPortAttrs: function (portName, index, total, selector, type) {
var attrs = {};
var portClass = 'port' + index;
var portSelector = selector + '>.' + portClass;
var portCircleSelector = portSelector + '>circle';
attrs[portCircleSelector] = {port: {id: portName || _.uniqueId(type), type: type}};
attrs[portSelector] = {ref: 'rect', 'ref-y': (index + 1) * (10 / total)};
if (selector === '.outPorts') {
attrs[portSelector]['ref-dx'] = 0;
}
return attrs;
}
}));
// Create a custom view for that element that displays an HTML div above it.
// -------------------------------------------------------------------------
joint.shapes.html.ElementView = joint.dia.ElementView.extend({
template: [
'<div class="html-element">',
'<button class="delete">x</button>',
'<span id="lbl" value="Please write here"></span>',
'<textarea id="txt" type="text" value="Please write here"></textarea>',
'</div>'
].join(''),
initialize: function () {
_.bindAll(this, 'updateBox');
joint.dia.ElementView.prototype.initialize.apply(this, arguments);
this.$box = $(_.template(this.template)());
// Prevent paper from handling pointerdown.
this.$box.find('input,select').on('mousedown click', function (evt) {
evt.stopPropagation();
});
// This is an example of reacting on the input change and storing the input data in the cell model.
this.$box.find('textarea').on('change', _.bind(function (evt) {
this.model.set('textarea', $(evt.target).val());
}, this));
this.$box.find('.delete').on('click', _.bind(this.model.remove, this.model));
// Update the box position whenever the underlying model changes.
this.model.on('change', this.updateBox, this);
// Remove the box when the model gets removed from the graph.
this.model.on('remove', this.removeBox, this);
this.updateBox();
this.listenTo(this.model, 'process:ports', this.update);
joint.dia.ElementView.prototype.initialize.apply(this, arguments);
},
render: function () {
joint.dia.ElementView.prototype.render.apply(this, arguments);
this.paper.$el.prepend(this.$box);
// this.paper.$el.mousemove(this.onMouseMove.bind(this)), this.paper.$el.mouseup(this.onMouseUp.bind(this));
this.updateBox();
return this;
},
renderPorts: function () {
var $inPorts = this.$('.inPorts').empty();
var $outPorts = this.$('.outPorts').empty();
var portTemplate = _.template(this.model.portMarkup);
_.each(_.filter(this.model.ports, function (p) {
return p.type === 'in'
}), function (port, index) {
$inPorts.append(V(portTemplate({id: index, port: port})).node);
});
_.each(_.filter(this.model.ports, function (p) {
return p.type === 'out'
}), function (port, index) {
$outPorts.append(V(portTemplate({id: index, port: port})).node);
});
},
update: function () {
// First render ports so that `attrs` can be applied to those newly created DOM elements
// in `ElementView.prototype.update()`.
this.renderPorts();
joint.dia.ElementView.prototype.update.apply(this, arguments);
},
updateBox: function () {
// Set the position and dimension of the box so that it covers the JointJS element.
var bbox = this.model.getBBox();
// Example of updating the HTML with a data stored in the cell model.
// paper.on('blank:pointerdown', function(evt, x, y) { this.$box.find('textarea').toBack(); });
this.$box.find('span').text(this.model.get('textarea'));
this.model.on('cell:pointerclick', function (evt, x, y) {
this.$box.find('textarea').toFront();
});
this.$box.css({width: bbox.width, height: bbox.height, left: bbox.x, top: bbox.y, transform: 'rotate(' + (this.model.get('angle') || 0) + 'deg)'});
},
removeBox: function (evt) {
this.$box.remove();
}
});
// Create JointJS elements and add them to the graph as usual.
// -----------------------------------------------------------
var el1 = new joint.shapes.html.Element({
position: {x: 600, y: 250},
size: {width: 170, height: 100},
inPorts: ['in'],
outPorts: ['out'],
textarea: 'Start writing'
});
var el2 = new joint.shapes.html.Element({
position: {x: 600, y: 400},
size: {width: 170, height: 100},
inPorts: ['in'],
outPorts: ['out'],
textarea: 'Start writing'
});
graph.addCells([el1, el2]);
同时，是否有可能根据文本区域内的文本来缩放SVG形状？