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
| Specification | Status | Comment |
|---|---|---|
| Filter Effects Module Level 1 The definition of 'preserveAlpha' in that specification. |
Working Draft | No change |
| Scalable Vector Graphics (SVG) 1.1 (Second Edition) The definition of 'preserveAlpha' in that specification. |
Recommendation | Initial definition |
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