Attribute key for the transform of a font. Values are instances of TransformAttribute. The default value is TransformAttribute.IDENTITY.

The TransformAttribute class defines the constant IDENTITY.

This corresponds to the transform passed to Font.deriveFont(AffineTransform). Since that transform is mutable and TextAttribute values must not be, the TransformAttribute wrapper class is used.

The primary intent is to support scaling and skewing, though other effects are possible.

Some transforms will cause the baseline to be rotated and/or shifted. The text and the baseline are transformed together so that the text follows the new baseline. For example, with text on a horizontal baseline, the new baseline follows the direction of the unit x vector passed through the transform. Text metrics are measured against this new baseline. So, for example, with other things being equal, text rendered with a rotated TRANSFORM and an unrotated TRANSFORM will measure as having the same ascent, descent, and advance.

In styled text, the baselines for each such run are aligned one after the other to potentially create a non-linear baseline for the entire run of text. For more information, see TextLayout.getLayoutPath.