Test as the APPX Runtime Account

Repeat the same test as the account used by the APPX session, using its selected PHP and configuration. On Linux, an administrator can run:

sudo -u appx /usr/bin/php \
  /opt/appx-chart-examples/chart-smoke.php \
  /opt/ChartDirector/lib/phpchartdir.php \
  /var/lib/appx-charts/smoke-appx-01.png

On Windows, use an authorized shell or scheduled task running under the actual account. Do not assume a mapped drive, interactive user's PATH or access token is available to the service. Prefer local absolute paths for the first test.

This check isolates PHP loading, fonts and filesystem access. APPX's native chart API adds its own parameter configuration and generated PHP. Complete the next chapter even when the standalone test succeeds.