cat: Canvas GUI
[[File:Extra500-Failuredialog-fuel.png|500px|right|Extra 500 - failure dialog - Fuel]]
== Extra500 failure dialog ==
# Initiate the listeners to make certain elements interactive
* Making the listeners and linking them to canvas/.svg elements (howto make clicking on it make it do something)
=== Namespace and Menu entry ===
This happens when the GEAR tab in the menu is pressed. The menu is re-setted and then the gear tab is changed color to indicate it is selected.
All the other pages are hidden, the gear page is show and finally all gear-buttons are updated. The status of the buttons depends on fg-properties. They have no listeners, but are only updated when the page is show. This is a bit easier and saves a lot of listeners. The disadvantage is that the buttons (they change color when a pressed and a failure is initiated) are not updated automatically. Maybe not ideal for a 'front end'...