UNIX Multi-Monitor Configurations
Because the UNIX platform encompasses multiple vendors, multi-monitor support can be more complex to configure. There are two primary multi-monitor solutions for UNIX platforms:
- Use the X Multi-Screen mechanism, wherein a distinct X11 Screen is displayed on each monitor to create multiple desktops. IDL supports this mechanism on all UNIX systems.
- Use the XINERAMA extension to create a single extended desktop. IDL 6.3 provides client support for the XINERAMA extension Macintosh OS X and several Linux distributions.
Note
Configure your UNIX multi-monitor systems using XINERAMA wherever possible. This gives you the most functionality and increases commonality with Windows.
Using X Multi-Screen
An X server running on a computer using multiple monitors can be configured so that a different Screen is assigned to each monitor. This is the traditional way for a UNIX system to support multiple monitors, and it is the only option available on IDL platforms for which there is no XINERAMA support.
In a multi-screen configuration, windows and dialogs cannot be dragged between windows interactively, and cannot span multiple monitors. Each monitor has a different display name and coordinate system with its own origin.
Using XINERAMA
The XINERAMA extension creates an extended desktop similar to that presented on Windows systems. Windows and dialogs can be dragged between windows interactively, and can span multiple monitors. All configured monitors share the same display name and have a common origin.
Stable XINERAMA support is only available on selected X Windows System releases. As of the IDL 6.3 release, IDL provides client support on Macintosh OS X and several Linux distributions. In addition, If the X server is running Macintosh OS X, Linux, or Solaris 10, IDL can treat multiple monitors as an extended desktop even though no information about individual monitor geometries is available.
UNIX systems that provide XINERAMA support are rarely configured to do so by default; consult your operating system documentation for configuration information. Some vendors supply configuration tools and desktop management controls to help use their systems. In addition, some X window managers are "XINERAMA-aware" and let you configure some multi-monitor-related behaviors.
Warning
Third-party desktop managers may enforce their own positioning rules, overriding requests from other applications such as IDL. If you have trouble positioning windows on the screen using IDL, investigate whether your desktop manager's control over other applications can be changed or relaxed.
XINERAMA Client/Server Interactions
When using networked UNIX systems, you are generally seated at an X workstation that is running an X server and some local programs such as command shells. You then log in remotely to another machine and execute X client programs (like IDL) with their DISPLAY environment variable pointing back to the X server you are using. The client program may be running on a machine that is of completely different architecture and capability than the machine running the X server. Table 5-6 shows the IDL X client's interactions with X servers on systems that do or do not support XINERAMA.
