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>
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…