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/SVG

preserveAlpha

the preserveAlpha attribute indicates how a <feConvolveMatrix> element handled alpha transparency.

Only one element is using this attribute: <feConvolveMatrix>

<svg viewBox="0 0 420 200" xmlns="http://www.w3.org/2000/svg">
  <filter id="convolveMatrix1" x="0" y="0" width="100%" height="100%">
    <feConvolveMatrix kernelMatrix="1 -1 2 0 0 0 0 0 -2" preserveAlpha="true"/>
  </filter>
  <filter id="convolveMatrix2" x="0" y="0" width="100%" height="100%">
    <feConvolveMatrix kernelMatrix="1 -1 2 0 0 0 0 0 -2" preserveAlpha="false"/>
  </filter>

  <image xlink:href="//developer.mozilla.org/files/6457/mdn_logo_only_color.png" width="200" height="200"
      style="filter:url(#convolveMatrix1);"/>
  <image xlink:href="//developer.mozilla.org/files/6457/mdn_logo_only_color.png" width="200" height="200"
      style="filter:url(#convolveMatrix2); transform:translateX(220px);"/>
</svg>

Usage notes

Default value false
Value true | false
Animatable Yes
true
This value indicates that the convolution will only apply to the color channels. In this case, the filter will temporarily unpremultiply the color component values and apply the kernel.
false
This value indicates that the convolution will apply to all channels, including the alpha channel.

Specifications

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
preserveAlpha ? ? ? ? ? ?
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
preserveAlpha ? ? ? ? ? ?

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/preserveAlpha