| Documentation / 4.2. Mobility Impairments | ||||
|---|---|---|---|---|
 | Chapter 4. Assistive Technologies | 4.3. Orca |  | |
| Documentation / 4.2. Mobility Impairments | ||||
|---|---|---|---|---|
| Chapter 4. Assistive Technologies | 4.3. Orca | | |
Mobility impairments can have many causes. Poor muscle control or weakness can make using standard keyboards and mouse devices difficult. For instance, some people are unable to type two keys simultaneously, while others tend to hit multiple keys or to bounce keys when pressing or releasing them. People who are able to use only one hand likewise have difficulties with some keyboard and mouse tasks.
The following sections describe how to modify the behavior of the mouse to suit your needs. To open the tool, choose ++.
To configure the mouse for left-handed use, click on the tab in the dialog and select the option. When you select this option, the system swaps the functions of the left and the right mouse button immediately.
If you have difficulty double-clicking, you can increase the period of time that the system allows to elapse between the first click and the second click of a double-click. For example, if the double-click timeout setting is 0.4 seconds, you must perform the second click of a double-click within 0.4 seconds of the first click. If the second click occurs more than 0.4 seconds after the first click, the system interprets the two clicks as two single clicks.
To configure the double-click timeout setting perform the following steps:
Click on the tab in the dialog.
Use the slider to specify the timeout in seconds that the system allows between the two clicks of a double-click. Moving the slider to the right will increase the timeout interval.
Double-click on the light bulb to the right of the slider to test the setting. If you perform the two clicks of the double-click within the timeout specified, the light bulb lights up fully to display a yellow glow around the bulb. If you do not double-click within the timeout specified, the light bulb does not light fully. You should increase the timeout setting and try again. When the light bulb lights, the timeout setting is suitable for your needs.
To change the size of the mouse pointer that is displayed on the desktop, click on the tab in the dialog. This will display a list of pointer themes and sizes available.
By default, GNOME does not include mouse pointer themes. For details on how to install and use pointer themes see Section 3.3.5, “Choosing a Theme”.
To configure the speed and sensitivity of the mouse, perform the following steps:
Click on the tab in the dialog.
In the section, use the slider to specify the speed at which the mouse pointer moves around the screen when you move the mouse.
If you select a low setting, the mouse pointer moves at a speed similar to the speed at which you are physically moving the mouse. This means that you need to physically move the mouse larger distances to cover the screen area. If you select a high setting, the mouse pointer moves at a faster speed than the speed at which you physically move the mouse. This means that you need to physically move the mouse smaller distances to cover the screen area.
Use the slider to specify how responsive the mouse pointer is to movements of the mouse. Moving the slider to the right will increase sensitivity and moving it to the left will decrease sensitivity.
Use the slider in the section to modify the distance that you must move an item with the pointer before the action is interpreted as a drag and drop action.
Use the tool to configure the keyboard accessibility options. To open the tool, choose ++. Accessibility options can be enabled by selecting the tab.
The GNOME On-Screen Keyboard (GOK) displays virtual keyboards on your desktop. You can use the standard mouse pointer or alternative pointing device to operate the virtual keyboards. GOK displays the following types of keyboards:
Composer Keyboards enable you to compose text. To type alphanumeric characters, select the characters on the composer keyboard.
Dynamic Keyboards reflect the applications that are currently running on the desktop. For example, On-Screen Keyboard generates dynamic keyboards that contain keys to represent the applications that are running on your desktop or the menus that are contained in an application.
You must enable assistive technology services before you are able to use many of the available tools.
Choose ++.
Select and press and .
Log back in. Assistive technology services are now activated.
If you are an On-Screen Keyboard user, you cannot use any application in Full-Screen mode because the application window obscures the On-Screen Keyboard display.
To resize the window for use with the On-Screen Keyboard application, perform the following steps:
Do not enable the Full-Screen mode in the application.
Give focus to the application window.
Press F10 to maximize the application.
