SVG Scaling Text to fit container

Maybe this could work for you. You'd have to tweak the values, but it does resize when the parent div resizes. Here's my dabblet example. It works similarly to fittext.js

I used the ‘viewBox’ & ‘preserveAspectRatio’ attributes.

<svg><text x="50%" y="50%" dy=".3em">Look, I’m centered!</text></svg>
<svg viewBox="-50 -50 100 100" preserveAspectRatio="xMidYMid meet"><text font-size="16" dy=".3em" >I’m also resizeable!</text></svg>

other resources I looked at:

• Making Sense of SVG viewBox's Madness
• How to Style Scalable Vector Graphics Using CSS

If you really don't care that the text gets ugly, here's how to fit unknown length text into a known width.

<svg width="436" height="180"
    style="border:solid 6px"
    xmlns="http://www.w3.org/2000/svg">
    <g>
        <text y="50%" textLength="436" lengthAdjust="spacingAndGlyphs">UGLY TEXT</text>
    </g>
</svg>

You can use the textPath tag in conjunction with the text tag. If you then set the lengthAdjust attribute of the textPath tag to "spacingAndGlyphs" (you may additionally use the method attribute and set it to "stretch" to adjust the rendering method).

Example:

<div style="width: 100%">
  <svg xmlns="http://www.w3.org/2000/svg"  preserveAspectRatio="xMinYMin meet" viewBox="0 0 200 100"
      style="border:solid 6px"
      xmlns="http://www.w3.org/2000/svg">
      <g>
      <path id="svg-text" d="M 10 50 H 180" fill="transparent" stroke="lightgray" />

          <text>
          <textPath
                xlink:href="#svg-text"
                method="stretch"
                lengthAdjust="spacingAndGlyphs"
              >Beautifully resized!</textPath>
          </text>
      </g>
  </svg>
<div>

Here is what I have come up with... Its similar to what other people have posted, but I think it resizes and scales nicely. This code will add spacing to any text roughly between 10-25 characters to make it fill the entire width of its parent. If you need longer or shorter text, just adjust the viewBox width and textLength attributes.

<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox='0 0 300 24'>
<text textLength='290' lengthAdjust="spacing" x='5' y="14" >
    Some Unknown Text that is resizing
</text>
</svg>