WARNING: this Class is for internal use ONLY. Compatibility is not guaranteed in future releases. The text layout for a single rectangular piece of text. The object does not own its text or format attributes but gets them from an interface class called MTmSource.

There are functions for setting the text, drawing it, and converting between x-y coordinates and document positions.

Ranges

All ranges of character positions and pixels include the start but not the end. This means that if a line is described by a TTmLineInfo object as starting at document position 345 and ending at 389, character positions 345 to 388 are in the line; 389 is in the next line if any.

Coordinates and units

All coordinates used in TAGMA classes and function arguments are in pixels and are relative to the origin of the object, which is the top left corner of the ordinary text, not including paragraph labels. Vertical coordinates increase from top to bottom.

Document format and positions

A TAGMA document, as supplied by the MTmSource interface, has a length as returned by MTmSource::DocumentLength of zero or more characters. It consists of Unicode text split into paragraphs by standard Unicode paragraph delimiters (character value 0x2029), so the number of paragraphs in the entire document is one more than the number of paragraph delimiters. A document position is a value in the range 0 to one more than the document length. Lines contain all document positions from their start to one less than their end position. These conventions allow all lines to end in a delimiter; the last line contains an imaginary paragraph end, which need not be supplied by the MTmSource interface, at a position equal to the document length. A CTmTextLayout object formatted for an empty document will thus have a start position (returned by StartChar) of 0 and an end position (returned by EndChar) of 1. WARNING: this Class is for internal use ONLY. Compatibility is not guaranteed in future releases.