[g-a-devel]Accessibility for gperfmeter

[Hema Seetharamaiah <hema seetharamaiah wipro com>]

Hi,

I am looking at gperfmeter (Performance Meter) for providing
accessibility. 

gperfmeter is used to monitor various parameters of system performance
like CPU, disk usage etc. The performance of each parameter can be
displayed by,

- strip chart showing the history of recent performance, and/or 
- a bar chart that shows current performace.

The no. of parameters (charts) to be displayed is configurable upto a
maximum of 10.

Both charts change color when the performance reaches a predefined (
configurable ) threshold. The two performance colors ( below and above
threshold ) are also configurable via a custom widget - ColorPicker.

Accessibility changes are required for the main window, the properties
dialog and the custom widget. 

I would like to seek clarifications regarding the main window whose
widget hierarchy is as follows,

GtkWindow
  |
  |-> GtkDrawingArea
  |
  |-> GtkMenuBar
        |
        |-> GtkMenuItem
        |
        |-> GtkMenuItem
        |
        |-> GtkMenuItem

A Pango Layout is created within the GtkDrawingArea where the meters are
drawn. All the graphs are drawn into the single drawing area.

Accessibility
-------------

1. The ATK interface - AtkAction is required because a right mouse click
within the GtkDrawingArea pops up a menu. I think I need to implement an
AtkObject to provide accessibility on behalf of the PangoLayout. This
would then implement the AtkAction.

The "<shift><f10>" currently does not pop up the menu. Would fixing that
suffice in which case AtkAction may not be needed?

2. Performance information is communicated in a highly visual manner (
using graphs ) and there is no supporting text information available.

a. Would a tooltip ( ATK description for the PangoLayout accessible
Object) containing a one line information of the current values
suffice?  

For e.g., "CPU 1%, disk 0, Errors 0" could be a tooltip if 3 meters are
displayed and this would get updated after every sampling. 

b. Since the location within the drawing area where the mouse is
pointing can be found, could the tooltip specifically describe the meter
in that area?

3. Additionally, color is used inform the user when a parameter crosses
a threshold. This doesnt seem very accessible.

If the threshold is crossed for a particular parameter, an additional
phrase "threshold crossed" could be added in the tooltip?

Kindly comment.

Regards,
Hema.

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