The following 3 text macro functions are delivering information about the existence of a picture in the stock list, a library file used in the stock list, or about an arbitrary file - usually a picture file used for foreground / bacground definition.
The functions will be replaced by a single integer number: 0, if the correspondig file/picture does not exists, or 1, it it is there. They can be used either directly in a text conditional expression { ? ? }, or in a more complex arithmetic expression.
%PICEX(<picture-name>) check, if a picture with the given name exists in the stock list.
Version parts ( the part of the picture name after a ~ , usually denoting the author of the picture
for cases, when the same vehicle, same technical variant and livery is drawn by multiple authors)
can be omitted, in that case the macor functions returns 1, when a picture only with that name,
or with an arbitrary version part exists.
%LIBEX(<library-name>) checks, if a picture library is available.
The picture libraries - both *.tvl and *.dll / *.exe libraries - have to be named
only by their base names - no drive, no path, no extension.
$FILEX(<file-name>) checks, if an arbitrary file - usually a background picture in *.jpg, *.png or *.gif format - is available.
The extension of the file have to be given.
If the <file-name> contains the path - starting with a drive letter followed by semicolon,
or by a backslash character -, the file will be checken only on that place.
If the <file-name> does not contain the path, both the directory of the stock list file,
and the directory of the main timetable file is checked for the file.
Of course, this functions are not for the first steps of crating a new timetable file. Who "plays" with traffic, uses, what he sees, what is available. But when creating the timetable delivered together with the Traffic program, it is already a vital possibility. The Traffic Installer offers the opportunity to select among the picture libraries, which ones the user wants to install, and what not. Similarly, the user also can select among the archives of the background images, which groups to install and which zip collections not. Using the Internet Install, which downloads the needed files "on the fly", only, when they are selected for installing, it could save both time,amount of downloaded data and harddisk capacity. With the sizes of today's computers and speed of the internet connections it is not an important aspect for the most of the users of Traffic, but the possibility is there. Additionally - and in the older days more importantly - there were picture sets not available free of charge. The usage of the MM&MM V3 drawings were bound to an existing licence of the screensaver, and NEK (Nimo Extension Kit) images were downloadable only for the subscribers of the package. These days both are aged, and therefore available for everybody.