Orca--Take the Killer Whale for a Ride
When you log in to your GNOME desktop for the first time, the AT-SPI infrastructure typically is not enabled. As a result, Orca isn't able to provide access to your desktop. You can enable accessibility in a number of ways, one being the Assistive Technology Preferences dialog available from the GNOME Preferences menu. Assuming you can't see the display, however, this dialog is useless to you if accessibility has not yet been enabled.
To get started quickly with Orca, you can use the talking text-based setup utility: orca --text-setup. BrlTTY users typically will run this from a virtual console. Below is an example of using orca --text-setup to set up Orca for use with speech and the Braille monitor:
bash-3.2$ orca --text-setup Welcome to Orca setup. Select desired voice: 1. kevin (en_US) 2. kevin16 (en_US) Enter choice: 2 Enable echo by word? Enter y or n: n Enable key echo? Enter y or n: n Select desired keyboard layout. 1. Desktop 2. Laptop Enter choice: 1 Enable Braille? Enter y or n: n Enable Braille Monitor? Enter y or n: y Setup complete. Press Return to continue.
If you have never done anything with accessibility on your desktop before, you typically will need to log out of your desktop session after running orca --text-setup. The desktop needs to be restarted with accessibility enabled. Once you have run orca --text-setup, accessibility is enabled for future logins to your desktop.
After you have logged out and logged back in, you can perform finer-grained customization of Orca's features using the Orca configuration GUI. The Orca configuration GUI is available any time Orca is running by pressing Insert-spacebar (desktop keyboard layout) or Caps Lock-spacebar (laptop keyboard layout) at the same time. You also can start Orca with the Preferences dialog by running orca --setup. More information on the Orca's configurable options can be found on the “Configuring and Using Orca” page of the Orca Wiki.
If you want Orca to start automatically when you log in, use the Assistive Technology Preferences dialog available from the GNOME Preferences menu. Press the Preferred Applications button in this dialog and navigate to the Accessibility tab. On the Accessibility tab, you can select Orca and also check the Run at start check box. Many users, however, merely run the orca command by using the Run Application dialog available via the Alt-F2 key binding on many distributions.
The Orca team refers to Orca's default operating mode as focus tracking mode. In focus tracking mode, you interact with any application (as any user would) using the built-in keyboard navigation mechanisms of GNOME. As you tab around the interface or interact with objects, such as pressing the spacebar to toggle check boxes or typing text into text areas, Orca presents the information to you via the combinations of speech, Braille and/or magnification that you have specified. That is, you merely interact with applications without needing to know any extra Orca keyboard commands.
Note to application developers: a quick sanity check for testing your application is to run Orca with speech and the Braille monitor enabled. Then, interact with your application using the keyboard alone. If speech and the Braille monitor seem to be updating with appropriate output as you interact with your application, you are doing a great job so far. If speech and/or the braille monitor are doing unexpected things, such as talking too much or not presenting anything at all, you have some work to do. Fear not, the Orca team is willing to help you!
When you use an application for the first time, or if you just want to get a better idea of what is on the screen, you often may want to explore a window without changing anything inside it. This includes not even tabbing around the interface. As such, focus tracking mode may not always be useful, and you will need to use other features of Orca, such as flat review and where am I, that are controlled by key bindings specific to Orca. When you press these key bindings, nothing happens in the application. Instead, Orca just presents the information you have requested.
For example, you might want to read the contents of a window line by line, word by word, character by character and so on. The flat review feature takes over the desktop keypad keys to perform these functions. For example, keypad 7 reads the previous line and keypad 9 reads the next line. The remaining numerical keys on the keypad perform similar functions for reviewing by word and character.
You also may want to know more detail about the object that currently has focus, the title of the current window, the contents of the status bar (if it exists) and so on. The where am I feature provides key bindings to obtain this information. For example, use the keypad Enter key to obtain information about the current object. When you press Insert at the same time as the Enter key, Orca presents information about the window title and status bar, if one exists.
Note on Orca key bindings: although the keypad keys are an exception, most of Orca's key bindings require you to press the Orca key at the same time as another key. This is much like how the Ctrl, Alt and Shift modifiers are used. The Orca key is a made-up modifier that can be bound to any key on the keyboard. By default, the Insert key is used as the Orca key for the desktop layout, and the Caps Lock key is used as the Orca key for the laptop layout. When Orca is used, the Orca key is owned by Orca and no longer behaves as a normal key.
The flat review and where am I features are only a few of the operations you can access via Orca's key bindings. For a complete list of Orca's key bindings, browse the Key Bindings tab of the Orca configuration GUI. In this page tab, you also can redefine the Orca key bindings to suit your specific needs.
- The Tiny Internet Project, Part I
- Machine Learning with Python
- SUSECON 2016: Where Technology Reigns Supreme
- Download "Linux Management with Red Hat Satellite: Measuring Business Impact and ROI"
- Free Today: September Issue of Linux Journal (Retail value: $5.99)
- Bitcoin on Amazon! Sort of...
- Android Browser Security--What You Haven't Been Told
- Securing the Programmer
- The Many Paths to a Solution