Direct and reverse synchronization with SyncTEX

We present a new technology named SyncTEX used to synchronize between the TEX input and the output. 1 What is synchronization? Creating documents with the TEX typesetting system often requires two windows, one for entering the text, the other one for viewing the resulting output. In general, documents are too long to fit in the visible frame of a window on screen, and what is really visible is only some part of either the input or the output. We say that the input view and the output view are synchronized if they are displaying the “same” portion of the document. Forwards or direct synchronization is the ability, for an output viewer, to scroll the window to a part corresponding to a given location in the input file. Backwards or reverse synchronization is the ability, for a text editor, to scroll the text view to a part corresponding to a given location in the output file. Figure 1 is a screenshot illustrating SyncTEX supported in iTEXMac2, the TEX front end developed by the author on MacOS X. The top window is a text editor where an extract of the “Not so short introduction to LATEX2ε” is displayed. The word “lscommand” has been selected and the viewer window at the bottom automatically scrolled to the position of this word in the output, highlighting it with a small red arrow. The grey background was added afterwards in the bottom window for the sake of visibility on printed media.