问SVG文本中的自动换行

EN

<svg ...>

<switch>
<foreignObject x="20" y="90" width="150" height="200">
<p xmlns="http://www.w3.org/1999/xhtml">Text goes here</p>
</foreignObject>

<text x="20" y="20">Your SVG viewer cannot display html.</text>
</switch>

</svg>

<svg width="200" height="200"
    xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
 <defs>
  <!-- define lines for text lies on -->
  <path id="path1" d="M10,30 H190 M10,60 H190 M10,90 H190 M10,120 H190"></path>
 </defs>
 <use xlink:href="#path1" x="0" y="35" stroke="blue" stroke-width="1" />
 <text transform="translate(0,35)" fill="red" font-size="20">
  <textPath xlink:href="#path1">This is a long long long text ......</textPath>
 </text>
</svg>

function wraptorect(textnode, boxObject, padding, linePadding) {

    var x_pos = parseInt(boxObject.getAttribute('x')),
    y_pos = parseInt(boxObject.getAttribute('y')),
    boxwidth = parseInt(boxObject.getAttribute('width')),
    fz = parseInt(window.getComputedStyle(textnode)['font-size']);  // We use this to calculate dy for each TSPAN.

    var line_height = fz + linePadding;

// Clone the original text node to store and display the final wrapping text.

   var wrapping = textnode.cloneNode(false);        // False means any TSPANs in the textnode will be discarded
   wrapping.setAttributeNS(null, 'x', x_pos + padding);
   wrapping.setAttributeNS(null, 'y', y_pos + padding);

// Make a copy of this node and hide it to progressively draw, measure and calculate line breaks.

   var testing = wrapping.cloneNode(false);
   testing.setAttributeNS(null, 'visibility', 'hidden');  // Comment this out to debug

   var testingTSPAN = document.createElementNS(null, 'tspan');
   var testingTEXTNODE = document.createTextNode(textnode.textContent);
   testingTSPAN.appendChild(testingTEXTNODE);

   testing.appendChild(testingTSPAN);
   var tester = document.getElementsByTagName('svg')[0].appendChild(testing);

   var words = textnode.textContent.split(" ");
   var line = line2 = "";
   var linecounter = 0;
   var testwidth;

   for (var n = 0; n < words.length; n++) {

      line2 = line + words[n] + " ";
      testing.textContent = line2;
      testwidth = testing.getBBox().width;

      if ((testwidth + 2*padding) > boxwidth) {

        testingTSPAN = document.createElementNS('http://www.w3.org/2000/svg', 'tspan');
        testingTSPAN.setAttributeNS(null, 'x', x_pos + padding);
        testingTSPAN.setAttributeNS(null, 'dy', line_height);

        testingTEXTNODE = document.createTextNode(line);
        testingTSPAN.appendChild(testingTEXTNODE);
        wrapping.appendChild(testingTSPAN);

        line = words[n] + " ";
        linecounter++;
      }
      else {
        line = line2;
      }
    }

    var testingTSPAN = document.createElementNS('http://www.w3.org/2000/svg', 'tspan');
    testingTSPAN.setAttributeNS(null, 'x', x_pos + padding);
    testingTSPAN.setAttributeNS(null, 'dy', line_height);

    var testingTEXTNODE = document.createTextNode(line);
    testingTSPAN.appendChild(testingTEXTNODE);

    wrapping.appendChild(testingTSPAN);

    testing.parentNode.removeChild(testing);
    textnode.parentNode.replaceChild(wrapping,textnode);

    return linecounter;
}

document.getElementById('original').onmouseover = function () {

    var container = document.getElementById('destination');
    var numberoflines = wraptorect(this,container,20,1);
    console.log(numberoflines);  // In case you need it

};