Transformation of text

Transformations of text are strategies to perform geometric transformations on text (reversal, rotations, etc.), particularly in systems that do not natively support transformation, such as HTML, seven-segment displays and plain text.

Implementation

Many systems, such as HTML, seven-segment displays and plain text, do not support transformation of text. In the case of HTML, this limitation in display may eventually be addressed through standard cascading style sheets (CSS), since proposed specifications for CSS3 include rotation for block elements. In the meantime, several ways of producing the visual effects of text transformations have come into use.

The most common of these transformations are rotation and reflection.

Unicode supports a variety of characters that resemble transformed characters, primarily for various forms of phonetic transcription. Each of these character names indicates what kind of transformation the characters have undergone:

Reversed characters, those that have been reflected in a vertical line, or flipped horizontally, like certain Cyrillic script letters;

Inverted characters, those that have been reflected on a horizontal line (i.e., flipped vertically, rare);

Turned characters, those that have been rotated 180 degrees and thus appear upside-down (this is the most common);

Sideways characters, those that have been rotated 90 degrees counterclockwise (generally the least supported, and used only for a handful of vowels in the Uralic Phonetic Alphabet system).

Upside-down text

Strategies can be used to render words upside down in languages such as HTML that do not permit rotation of text; using Unicode characters (especially those in the IPA), a very close approximation of upside-down text (also called flip text) can be achieved. The letters s, x, z, and o are rotationally symmetrical, while pairs such as b/q, d/p, and n/u are rotations of each other. Historically, capital J in early forms of italic type was designed in such a way that it could be turned upside down to render a pound sign, £.