Tarantella Administration Guide > Applications, documents and hosts > Users have problems displaying high color X applications

Users have problems displaying high color X applications

Several problems can occur when displaying high color X applications:

• User receives a "client not capable error"
• The X application fails with "can't allocate enough color planes" error (or similar)
• The colors appear strange
• The X application uses too much bandwidth
• The color quality declines when a session is shadowed
• 8-bit applications exit with a PseudoColor visual error

User receives a "client not capable error"

If a user receives a "client not capable error", they are using an old version of the Tarantella Native Client or they are not using the latest Tarantella Java™ archives. To be able to view 16 and 24-bit applications, they must upgrade to the latest version of the Native Client or make sure they download the latest archives.

The X application fails with "can't allocate enough color planes" error (or similar).

If an X application fails to run and exits with errors such as "can't allocate enough color planes", the application probably only displays 8-bit color. Check the display specification of the application and adjust the color depth setting.

The colors appear strange

If there are any problems with appearance in 16-bit or 24-bit color applications, set the quality to full, that is:

• 24 for 24-bit applications, and
• 16 for 16-bit applications.

This should correct any problems.

The X application uses too much bandwidth

If bandwidth is critical, try quality levels 6 and 9. However there is no guarantee on the bandwidth saving or how badly the appearance will be affected.

The color quality declines when a session is shadowed

If you shadow a user's session, either you or the user may experience a decline in the color quality.

If you and the user have different color depth settings, the color format will be converted and colors dithered. To avoid this, increase the color depth (--depth) of the Object Manager to 16-bit or 24-bit.

For the two sessions to match exactly both the color depth (--depth) and color quality (--quality) of the two sessions need to match. If the quality settings are auto or best, you may end up with different color quality levels to that of the user (for example if the user is on a low bandwidth connection and you have a high bandwidth connection).

8-bit applications exit with a PseudoColor visual error

If you run an 8-bit application within a 16 or 24-bit high color X application session, for example from a CDE desktop, you may find the application exits with an error such as "Cannot find a matching 8-bit PseudoColor visual".

To fix this, change the color depth (--depth) of the X application to 16/8 or 24/8 so that it supports multiple color depths.

Note There are memory and performance effects of using these settings.

If the 8-bit application requires the primary color depth to be 8-bit (rather than 16 or 24-bit), the application may still exit. If this happens, the solution is to run the 8-bit application in a separate Tarantella session.