GUI Capture (Developement)

This information is not up to date and needs some cleanup.

Overall structure

Gui capture overall structure.png

Platform independence

For the output to remain independent from the platform, the engine passes the events in a uniform format to the output which can use the process_xy_event features inherited from the CAPTURE_EVENT_VISITOR class to generate the output. The input is generated by the engine implementation which is specific for the platform used.

Capture Engine

The engine has the tasks:

  • start the application
  • read events until application finished
  • send the events to the output handler
  • (filter events?)

Event Hierarchy

Gui capture event hierarchy.png

To allow different output formats, the events types are equipped with a process feature which implements the visitor pattern together with the CAPTURE_EVENT_VISITOR class.

Event Data

The event has to store the necessary data to replay it (raw data) but should also store additional information like the widget it happened on. This could be done by giving all widgets (or just the important ones) a name and storing that name along with the event data.

The widget which was accessed has to be accessed through Vision2 which poses some problems for the capturing process on how to communicate with the Vision2 application.

All Events:

  • Vision2 widget name (if applicable)

All Mouse Events:

  • x, y coordinate

Mouse Click Event:

  • Button state change

All Keyboard Events:

  • Key Code
  • Key state change

Windows Implementation

Event Hook

To get the events from another window, a hook can be installed. The hook is installed through a custom DLL. All messages which are sent to the window are then stored by the dll and can be polled by the capturing application.

How to get the widget name for an event is not yet clear. Since the name is only known in Vision2 the capturing application has to somehow call a feature on the window. This could probably be done by sending a special message to the window (through the windows message queue) which is then catched by Vision2. The name is then sent back by sending a message back through the windows message queue to the capturing application. Problem: other events can be processed in the meantime. The ordering of the events could be problematic

Native Functionality

needed functions:

  • start_capturing (process_id)
    install hook into process identified by 'process_id'
  • stop_capturing
    uninstall hook
  • has_event
    check event queue in custom DLL
  • pop_event: RAW_EVENT_DATA
    retrieve an event from the event queue
  • request_widget_name (x, y): STRING
    send a request to the window for the widget name

Unix Implementation

Not yet started

Output Formats

  • Eiffel Code
    Generate an Eiffel class to replay the event sequence. It should be easy to insert assertions into the code to create a testcase. Until the problems in the replaying phase are solved, the testcase has to be compiled together with the application, so the output formatter should be aware of that.
  • XML Data
    An XML output could be used to create a Bug Report from a customer and replay it on a player.