alignment-baseline
alignment-baseline 属性は、要素が親要素に対して配置される方法を指定します。このプロパティは、要素と親要素の対応するベースラインのどれを揃えるかを指定します。例えば、ローマ字のテキストでフォントサイズが変わった場合でも、アルファベットのベースラインを一定にすることが可能になります。既定値は alignment-baseline プロパティの計算値と同じ名前の値となります。
メモ: プレゼンテーション属性として、 alignment-baseline は CSS プロパティとして使用することができます。
プレゼンテーション属性として、あらゆる要素に適用できますが、効果があるのは <tspan>, <tref> (en-US), <altGlyph>, and <textPath> (en-US) の 4 つの属性のみです。
使用上の注意
| 値 |
auto | baseline | before-edge |
text-before-edge | middle |
central | after-edge |
text-after-edge | ideographic |
alphabetic | hanging |
mathematical | top | center |
bottom
|
|---|---|
| 既定値 | auto |
| アニメーション | 可 |
auto非推奨-
この値はその文字が所属する書法のドミナントベースラインです。すなわち、親のドミナントベースラインを使用します。
baseline-
Uses the dominant baseline choice of the parent. Matches the box’s corresponding baseline to that of its parent.
before-edge非推奨-
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.
メモ: 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非推奨-
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.
メモ: 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 vertical-align property.
例
html
<svg width="300" height="120" viewBox="0 0 300 120"
xmlns="http://www.w3.org/2000/svg">
<!-- Materialisation 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>
<!-- Materialisation 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>
他の要素 (<text> など) におけるオブジェクトの配置については、 dominant-baseline (en-US) を参照してください。
仕様書
| Specification |
|---|
| CSS Inline Layout Module Level 3 # alignment-baseline-property |
| Scalable Vector Graphics (SVG) 2 # AlignmentBaselineProperty |
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