CrossAxisAlignment enum

Place the children with their start edge aligned with the start side of the cross axis.

For example, in a column (a flex with a vertical axis) whose TextDirection is TextDirection.ltr, this aligns the left edge of the children along the left edge of the column.

If this value is used in a horizontal direction, a TextDirection must be available to determine if the start is the left or the right.

If this value is used in a vertical direction, a VerticalDirection must be available to determine if the start is the top or the bottom.

Place the children as close to the end of the cross axis as possible.

For example, in a column (a flex with a vertical axis) whose TextDirection is TextDirection.ltr, this aligns the right edge of the children along the right edge of the column.

If this value is used in a horizontal direction, a TextDirection must be available to determine if the end is the left or the right.

If this value is used in a vertical direction, a VerticalDirection must be available to determine if the end is the top or the bottom.

Place the children so that their centers align with the middle of the cross axis.

This is the default cross-axis alignment.

Require the children to fill the cross axis.

This causes the constraints passed to the children to be tight in the cross axis.

Place the children along the cross axis such that their baselines match.

Consider using this value for any horizontal main axis (as with Row) where the children primarily contain text. If the different children have text with different font metrics (for example because they differ in TextStyle.fontSize or other TextStyle properties, or because they use different fonts due to being written in different scripts), then this typically produces better visual alignment than the other CrossAxisAlignment values, which use no information about where the text sits vertically within its bounding box.

The baseline of a widget is typically the typographic baseline of the first text in the first Text or RichText widget it encloses, if any. The typographic baseline is a horizontal line used for aligning text, which is specified by each font; for alphabetic scripts, it ordinarily runs along the bottom of letters excluding any descenders.

Because baselines are always horizontal, this alignment is intended for horizontal main axes (as with Row). If the main axis is vertical (as with Column), then this value is treated like start.

For horizontal main axes, if the minimum height constraint passed to the flex layout exceeds the intrinsic height of the cross axis, children will be aligned as close to the top as they can be while honoring the baseline alignment. In other words, the extra space will be below all the children.

Children who report no baseline will be top-aligned.

See also:

• RenderBox.getDistanceToBaseline, which defines the baseline of a box.
• IgnoreBaseline, which can be used to ignore a child for the purpose of baseline alignment.