alignment-baseline

The alignment-baseline attribute specifies how an object is aligned with respect to its parent. This property specifies which baseline of this element is to be aligned with the corresponding baseline of the parent. For example, this allows {{glossary("/Baseline/Typography", "alphabetic baselines")}} in Roman text to stay aligned across font size changes. It defaults to the baseline with the same name as the computed value of the alignment-baseline property.

[!NOTE] As a presentation attribute, alignment-baseline also has a CSS property counterpart: {{cssxref("alignment-baseline")}}. When both are specified, the CSS property takes priority.

You can use this attribute with the following SVG elements:

• {{SVGElement("tspan")}}
• {{SVGElement("text")}}
• {{SVGElement("textPath")}}

Usage notes

• auto {{deprecated_inline}}

  • : The value is the dominant-baseline of the script to which the character belongs - i.e., use the dominant-baseline of the parent.

• baseline

  • : Uses the {{svgattr("dominant-baseline")}} choice of the parent. Matches the box's corresponding {{Glossary("baseline/typography", "baseline")}} to that of its parent.

• before-edge {{deprecated_inline}}

  • : The alignment-point of the object being aligned is aligned with the "before-edge" baseline of the parent text content element.

• text-bottom

  • : Matches the bottom of the box to the top of the parent's content area.

• text-before-edge

  • : The alignment-point of the object being aligned is aligned with the "text-before-edge" baseline of the parent text content element.

    [!NOTE] This keyword may be mapped to text-top.

• middle

  • : Aligns the vertical midpoint of the box with the baseline of the parent box plus half the x-height of the parent.

• central

  • : Matches the box's central baseline to the central baseline of its parent.

• after-edge {{deprecated_inline}}

  • : The alignment-point of the object being aligned is aligned with the "after-edge" baseline of the parent text content element.

• text-top

  • : Matches the top of the box to the top of the parent's content area.

• text-after-edge

  • : The alignment-point of the object being aligned is aligned with the "text-after-edge" baseline of the parent text content element.

    [!NOTE] This keyword may be mapped to text-bottom.

• ideographic

  • : Matches the box's ideographic character face under-side baseline to that of its parent.

• alphabetic

  • : Matches the box's alphabetic baseline to that of its parent.

• hanging

  • : The alignment-point of the object being aligned is aligned with the "hanging" baseline of the parent text content element.

• mathematical

  • : Matches the box's mathematical baseline to that of its parent.

• top

  • : Aligns the top of the aligned subtree with the top of the line box.

• center

  • : Aligns the center of the aligned subtree with the center of the line box.

• bottom

  • : Aligns the bottom of the aligned subtree with the bottom of the line box.

SVG 2 introduces some changes to the definition of this property. In particular: the values auto, before-edge, and after-edge have been removed. For backwards compatibility, text-before-edge may be mapped to text-top and text-after-edge to text-bottom. Neither text-before-edge nor text-after-edge should be used with the {{cssxref("vertical-align")}} property.

Example

<svg
  width="300"
  height="120"
  viewBox="0 0 300 120"
  xmlns="http://www.w3.org/2000/svg">
  <!-- Materialization of anchors -->
  <path
    d="M60,10 L60,110
              M30,10 L300,10
              M30,65 L300,65
              M30,110 L300,110
              "
    stroke="grey" />

  <!-- Anchors in action -->
  <text alignment-baseline="hanging" x="60" y="10">A hanging</text>

  <text alignment-baseline="middle" x="60" y="65">A middle</text>

  <text alignment-baseline="baseline" x="60" y="110">A baseline</text>

  <!-- Materialization of anchors -->
  <circle cx="60" cy="10" r="3" fill="red" />
  <circle cx="60" cy="65" r="3" fill="red" />
  <circle cx="60" cy="110" r="3" fill="red" />

  <style>
    <![CDATA[
      text {
        font: bold 36px Verdana, Helvetica, Arial, sans-serif;
      }
    ]]>
  </style>
</svg>

{{EmbedLiveSample("Example")}}

For object alignment in other elements (such as {{SVGElement("text")}}), see {{SVGAttr("dominant-baseline")}}.

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• CSS {{cssxref("alignment-baseline")}} property
• CSS baseline alignment