Properties and transformations¶
The RTE applications typically expect to be fed with content formatted as HTML. In effect an RTE will discard content it doesn't like, for instance fictitious HTML tags and line breaks. Also the HTML content created by the RTE editor is not necessarily as 'clean' as you might like.
The editor has the ability to paste in formatted content copied/cut from other websites (in which case images are included!) or from text processing applications like MS Word or Star Office. This is a great feature and may solve the issue of transferring formatted content from e.g. Word into TYPO3.
However these inherent features - good or bad - raises the issue how to handle content in a field which we do not wish to 'pollute' with unnecessary HTML-junk. One perspective is the fact that we might like to edit the content with Netscape later (for which the RTE cannot be used, see above) and therefore would like it to be 'human readable'. Another perspective is if we might like to use only Bold and Italics but not the alignment options. Although you can configure the editor to display only the bold and italics buttons, this does not prevent users from pasting in HTML-content copied from other websites or from Microsoft Word which does contain tables, images, headlines etc.
The answer to this problem is a so called 'transformation' which you can configure in the $TCA (global, authoritative configuration) and which you may further customize through Page TSconfig (local configuration for specific branches of the website). The issue of transformations is best explained by the following example from the table, tt_content (the content elements).