Mobility Impairments

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, others hit multiple keys or bounce keys when pressing or releasing them. People who are able to use only one hand often have difficulties with some keyboard and mouse tasks.

Mouse Behavior

The following sections describe how to modify the behavior of the mouse to suit your needs.

Mouse for Left-Handed Use

If you have difficulties using the right-handed mouse, you can change the mouse setting to left-handed. To configure the mouse for left-handed use, select Control Center+Mouse Preference and select the Left-handed mouse orientation. When you select this option, the system swaps the functions of the left and the right mouse button.

Double-Click Behavior

If you have difficulties double-clicking, you can increase the period of time that the system between the first 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 , select System+Control Center+Mouse Preferences and specify the Double-Click Timeout. 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 specified period, the light bulb energizes fully to display a yellow glow around the bulb. If you do not double-click within the timeout specified, the light bulb does not energize fully. You should increase the timeout setting and try again. When the light bulb energizes, the timeout setting is suitable for your needs.

Mouse Speed and Sensitivity

If you have dificulties with the behaviour of the pointer, you can change the speed and sensitivity of the pointer. To configure the speed and sensitivity of the pointer, select System+ Control Center+Mouse Preferences+General.

Use the Sensitivity slider to specify how responsive the 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 Drag and Drop 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.

If you select a low acceleration setting, the pointer moves at a speed similar to the speed at which you are physically moving the mouse or other pointer device. This means that you need to physically move the mouse larger distances to cover the screen area. If you select a high setting, the 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.

Accessible Keyboard

Use the Keyboard Preference tool to configure the keyboard accessibility options. To open the Keyboard Preference tool, choose System+ Control Center+Keyboard. Accessibility options can be enabled by selecting the Accessibility tab.

Accessible Mouse

Use the Mouse Preferences tool to configure the mouse accessibility options. To open the Mouse Preferences tool, choose System+ Control Center+Mouse Preferences. Accessibility options can be enabled by selecting the Accessibility tab.

GNOME On-Screen Keyboard

The GNOME On-Screen Keyboard (GOK) displays virtual keyboards on your desktop. You can use the standard pointer or an 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 Accessibility tools.

  1. Choose System+Control Center+Assistive Technologies.

  2. Select Enable assistive technologies and press Close and Log Out.

  3. Log back in. Assistive technology services are now activated.

Maximizing Application Windows

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:

  1. Do not enable the Full-Screen mode in the application.

  2. Give focus to the application window.

  3. Press F10 to maximize the application.