内容表

• 范例
• 用法注意事项
• 规范
• 浏览器兼容性

preserveAlpha

1. SVG 元素

   1. A
      1. <a>
      2. <altGlyph>
      3. <altGlyphDef>
      4. <altGlyphItem>
      5. <animate>
      6. <animateColor>
      7. <animateMotion>
      8. <animateTransform>
   2. B-C
      1. <circle>
      2. <clipPath>
      3. <color-profile>
      4. <cursor>
   3. D
      1. <defs>
      2. <desc>
   4. E
      1. <ellipse>
   5. F
      1. <feBlend>
      2. <feColorMatrix>
      3. <feComponentTransfer>
      4. <feComposite>
      5. <feConvolveMatrix>
      6. <feDiffuseLighting>
      7. <feDisplacementMap>
      8. <feDistantLight>
      9. <feFlood>
      10. <feFuncA>
      11. <feFuncB>
      12. <feFuncG>
      13. <feFuncR>
      14. <feGaussianBlur>
      15. <feImage>
      16. <feMerge>
      17. <feMergeNode>
      18. <feMorphology>
      19. <feOffset>
      20. <fePointLight>
      21. <feSpecularLighting>
      22. <feSpotLight>
      23. <feTile>
      24. <feTurbulence>
      25. <filter>
      26. <font>
      27. <font-face>
      28. <font-face-format>
      29. <font-face-name>
      30. <font-face-src>
      31. <font-face-uri>
      32. <foreignObject>
   6. G
      1. <g>
      2. <glyph>
      3. <glyphRef>
   7. H
      1. <hkern>
   8. I
      1. <image>
   9. J-L
      1. <line>
      2. <linearGradient>
   10. M
       1. <marker>
       2. <mask>
       3. <metadata>
       4. <missing-glyph>
       5. <mpath>
   11. N-P
       1. <path>
       2. <pattern>
       3. <polygon>
       4. <polyline>
   12. Q-R
       1. <radialGradient>
       2. <rect>
   13. S
       1. <script>
       2. <set>
       3. <stop>
       4. <style>
       5. <svg>
       6. <switch>
       7. <symbol>
   14. T
       1. <text>
       2. <textPath>
       3. <title>
       4. <tref>
       5. <tspan>
   15. U
       1. <use>
   16. V-Z
       1. <view>
       2. <vkern>

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

You can use this attribute with the following SVG elements:

• <feConvolveMatrix>

范例

html, body, svg {
  height: 100%;
}

					

<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>

					

用法注意事项

默认值	false
值	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.

规范

规范	状态	注释
Filter Effects Module Level 1 The definition of 'preserveAlpha' in that specification.	工作草案	无变化
Scalable Vector Graphics (SVG) 1.1 (Second Edition) The definition of 'preserveAlpha' in that specification.	推荐	初始定义

浏览器兼容性

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最后修改： Sep 23, 2021 , 由 MDN 贡献者