Pure SVG way to fit text to a box

Question

Box size known. Text string length unknown. Fit text to box without ruining its aspect ratio.

Answer 1

first of all: just saw that the answer doesn't precisely address your need - it might still be an option, so here we go:

you are rightly observing that svg doesn't support word-wrapping directly. however, you might benefit from foreignObject elements serving as a wrapper for xhtml fragments where word-wrapping is available.

have a look at this self-contained demo (available online):

<?xml version="1.0" encoding="utf-8"?>
<!-- SO: http://stackoverflow.com/questions/15430189/pure-svg-way-to-fit-text-to-a-box  -->
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg"
   xmlns:xhtml="http://www.w3.org/1999/xhtml"
   xmlns:xlink="http://www.w3.org/1999/xlink"
   version="1.1"
   width="20cm" height="20cm"
   viewBox="0 0 500 500"
   preserveAspectRatio="xMinYMin"
   style="background-color:white; border: solid 1px black;"
>
  <title>simulated wrapping in svg</title>
  <desc>A foreignObject container</desc>

   <!-- Text-Elemente -->
   <foreignObject
      x="100" y="100" width="200" height="150"
      transform="translate(0,0)"
   >
      <xhtml:div style="display: table; height: 150px; overflow: hidden;">
         <xhtml:div style="display: table-cell; vertical-align: middle;">
            <xhtml:div style="color:black; text-align:center;">Demo test that is supposed to be word-wrapped somewhere along the line to show that it is indeed possible to simulate ordinary text containers in svg.</xhtml:div>
         </xhtml:div>
      </xhtml:div>
   </foreignObject>

  <rect x="100" y="100" width="200" height="150" fill="transparent" stroke="red" stroke-width="3"/>
</svg>

Answer 2

I've developed @Roberto answer, but instead of transforming (scaling) the textNode, we simply:

• give it font-size of 1em to begin with
• calculate the scale based on getBBox
• set the font-size to that scale

(You can also use 1px etc.)

Here's the React HOC that does this:

import React from 'react';
import TextBox from './TextBox';

const AutoFitTextBox = TextBoxComponent =>
  class extends React.Component {
    constructor(props) {
      super(props);
      this.svgTextNode = React.createRef();
      this.state = { scale: 1 };
    }

    componentDidMount() {
      const { width, height } = this.props;
      const textBBox = this.getTextBBox();
      const widthScale = width / textBBox.width;
      const heightScale = height / textBBox.height;
      const scale = Math.min(widthScale, heightScale);

      this.setState({ scale });
    }

    getTextBBox() {
      const svgTextNode = this.svgTextNode.current;
      return svgTextNode.getBBox();
    }

    render() {
      const { scale } = this.state;
      return (
        <TextBoxComponent
          forwardRef={this.svgTextNode}
          fontSize={`${scale}em`}
          {...this.props}
        />
      );
    }
  };

export default AutoFitTextBox(TextBox);

Answer 3

I didn't find a way to do it directly without Javascript, but I found a JS quite easy solution, without for loops and without modify the font-size and fits well in all dimensions, that is, the text grows until the limit of the shortest side.

Basically, I use the transform property, calculating the right proportion between the desired size and the current one.

This is the code:

<?xml version="1.0" encoding="UTF-8" ?>
<svg version="1.2" viewBox="0 0 1000 1000" width="1000" height="1000" xmlns="http://www.w3.org/2000/svg" >
 <text id="t1" y="50" >MY UGLY TEXT</text>
 <script type="application/ecmascript"> 

    var width=500, height=500;

    var textNode = document.getElementById("t1");
    var bb = textNode.getBBox();
    var widthTransform = width / bb.width;
    var heightTransform = height / bb.height;
    var value = widthTransform < heightTransform ? widthTransform : heightTransform;
    textNode.setAttribute("transform", "matrix("+value+", 0, 0, "+value+", 0,0)");

 </script>
</svg>

In the previous example the text grows until the width == 500, but if I use a box size of width = 500 and height = 30, then the text grows until height == 30.

Answer 4

I don't think its the solution for what you want to do but you can use textLength with percentage ="100%" for full width.

<svg width="436" height="180"
    style="border:solid 6px"
    xmlns="http://www.w3.org/2000/svg">
    <text x="0%" y="50%" textLength="100%">blabla</text>
</svg>

you can also add textanchor="middle" and change the x position to center perfectly your text

this will not change the fontsize and you will have weird space letterspacing...

JSFIDDLE DEMO