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dominant-baseline

The dominant-baseline attribute specifies the dominant baseline, which is the baseline used to align the box’s text and inline-level contents. It is also indicates the default alignment baseline of any boxes participating in baseline alignment in the box’s alignment context.

is used to determine or re-determine a scaled-baseline-table. A scaled-baseline-table is a compound value with three components: a baseline-identifier for the dominant-baseline, a baseline-table and a baseline-table font-size. Some values of the property re-determine all three values; other only re-establish the baseline-table font-size. When the initial value, auto, would give an undesired result, this property can be used to explicitly set the desire scaled-baseline-table.

If there is no baseline table in the nominal font or if the baseline table lacks an entry for the desired baseline, then the browser may use heuristics to determine the position of the desired baseline.

Note: As a presentation attribute, dominant-baseline can be used as a CSS property. See css dominant-baseline for further information.

As a presentation attribute, it can be applied to any element but it only has effect on text content elements, including: <altGlyph>, <text>, <textPath>, <tref>, and <tspan>

<svg viewBox="0 0 200 120" xmlns="http://www.w3.org/2000/svg">
    <path d="M20,20 L180,20 M20,50 L180,50 M20,80 L180,80" stroke="grey" />
    
    <text dominant-baseline="baseline" x="30" y="20">Baseline</text>
    <text dominant-baseline="middle" x="30" y="50">Middle</text>
    <text dominant-baseline="hanging" x="30" y="80">Hanging</text>
</svg>

Usage notes

Value auto | text-bottom | alphabetic | ideographic | middle | central | mathematical | hanging | text-top
Default value auto
Animatable Yes
auto

If this property occurs on a <text> element, then the computed value depends on the value of the writing-mode attribute. If the writing-mode is horizontal, then the value of the dominant-baseline component is alphabetic, else if the writing-mode is vertical, then the value of the dominant-baseline component is central

If this property occurs on a <tspan>, <tref>, <altGlyph> or <textPath> element, then the dominant-baseline and the baseline-table components remain the same as those of the parent text content element. If the computed baseline-shift value actually shifts the baseline, then the baseline-table font-size component is set to the value of the font-size attribute on the element on which the dominant-baseline attribute occurs, otherwise the baseline-table font-size remains the same as that of the element. If there is no parent text content element, the scaled-baseline-table value is constructed as above for <text> elements.

use-script
The dominant-baseline and the baseline-table components are set by determining the predominant script of the character data content. The writing-mode, whether horizontal or vertical, is used to select the appropriate set of baseline-tables and the dominant baseline is used to select the baseline-table that corresponds to that baseline. The baseline-table font-size component is set to the value of the font-size attribute on the element on which the dominant-baseline attribute occurs.
no-change
The dominant-baseline, the baseline-table, and the baseline-table font-size remain the same as that of the parent text content element.
reset-size
The dominant-baseline and the baseline-table remain the same, but the baseline-table font-size is changed to the value of the font-size attribute on this element. This re-scales the baseline-table for the current font-size.
ideographic
The baseline-identifier for the dominant-baseline is set to be ideographic, the derived baseline-table is constructed using the ideographic baseline-table in the font, and the baseline-table font-size is changed to the value of the font-size attribute on this element.
alphabetic
The baseline-identifier for the dominant-baseline is set to be alphabetic, the derived baseline-table is constructed using the alphabetic baseline-table in the font, and the baseline-table font-size is changed to the value of the font-size attribute on this element.
hanging
The baseline-identifier for the dominant-baseline is set to be hanging, the derived baseline-table is constructed using the hanging baseline-table in the font, and the baseline-table font-size is changed to the value of the font-size attribute on this element.
mathematical
The baseline-identifier for the dominant-baseline is set to be mathematical, the derived baseline-table is constructed using the mathematical baseline-table in the font, and the baseline-table font-size is changed to the value of the font-size attribute on this element.
central
The baseline-identifier for the dominant-baseline is set to be central. The derived baseline-table is constructed from the defined baselines in a baseline-table in the font. That font baseline-table is chosen using the following priority order of baseline-table names: ideographic, alphabetic, hanging, mathematical. The baseline-table font-size is changed to the value of the font-size attribute on this element.
middle
The baseline-identifier for the dominant-baseline is set to be middle. The derived baseline-table is constructed from the defined baselines in a baseline-table in the font. That font baseline-table is chosen using the following priority order of baseline-table names: alphabetic, ideographic, hanging, mathematical. The baseline-table font-size is changed to the value of the font-size attribute on this element.
text-after-edge
The baseline-identifier for the dominant-baseline is set to be text-after-edge. The derived baseline-table is constructed from the defined baselines in a baseline-table in the font. The choice of which font baseline-table to use from the baseline-tables in the font is browser dependent. The baseline-table font-size is changed to the value of the font-size attribute on this element.
text-before-edge
The baseline-identifier for the dominant-baseline is set to be text-before-edge. The derived baseline-table is constructed from the defined baselines in a baseline-table in the font. The choice of which baseline-table to use from the baseline-tables in the font is browser dependent. The baseline-table font-size is changed to the value of the font-size attribute on this element.
text-top
This value uses the top of the em box as the baseline.

Example

SVG

<svg width="400" height="300" viewBox="0 0 300 300"
    xmlns="http://www.w3.org/2000/svg">

  <!-- Materialization of anchors -->
  <path d="M60,20 L60,270
           M30,20 L400,20
           M30,70 L400,70
           M30,120 L400,120
           M30,170 L400,170
           M30,220 L400,220
           M30,270 L400,270" stroke="grey" />
    
    <!-- Anchors in action -->
    <text dominant-baseline="auto" x="70" y="20">auto</text>
    <text dominant-baseline="middle" x="70" y="70">middle</text>
    <text dominant-baseline="baseline" x="70" y="120">baseline</text>
    <text dominant-baseline="hanging" x="70" y="170">hanging</text>
    <text dominant-baseline="mathematical" x="70" y="220">mathematical</text>
    <text dominant-baseline="text-top" x="70" y="270">text-top</text>

  <!-- Materialization of anchors -->
  <circle cx="60" cy="20" r="3" fill="red" />
  <circle cx="60" cy="70" r="3" fill="red" />
  <circle cx="60" cy="120" r="3" fill="red" />
  <circle cx="60" cy="170" r="3" fill="red" />
  <circle cx="60" cy="220" r="3" fill="red" />
  <circle cx="60" cy="270" r="3" fill="red" />

  <style><![CDATA[
  text {
    font: bold 30px Verdana, Helvetica, Arial, sans-serif;
  }
  ]]></style>
</svg>

Result

Specifications

Specification Status Comment
Scalable Vector Graphics (SVG) 2
The definition of 'dominant-baseline' in that specification.
Candidate Recommendation Refers to the specification in Working Draft and explicitly mentions the removal of the values use-script, no-change, and reset-size.
CSS Inline Layout
The definition of 'dominant-baseline' in that specification.
Working Draft Removed the values use-script, no-change, and reset-size and introduced the text-top value.
Scalable Vector Graphics (SVG) 1.1 (Second Edition)
The definition of 'dominant-baseline' in that specification.
Recommendation Initial definition

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
dominant-baselineChrome ? Edge ? Firefox ? IE ? Opera ? Safari ? WebView Android ? Chrome Android ? Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android ?

Legend

Compatibility unknown  
Compatibility unknown

See also

Document Tags and Contributors

Last updated by: Sebastianz,