What is a graphics tablet?
A graphics tablet replaces the mouse with a pen for work that needs a natural hand motion: illustration, photo retouching, signatures, handwritten notes and annotation. CompTIA's term is drawing pad. There are two main forms:
- Pen tablet: a flat pad with no screen. You draw on the pad while watching the monitor.
- Pen display: a tablet with a built-in screen, so you draw directly on the image. It needs a video connection as well as USB.
Tablets and 2-in-1 laptops with an active pen offer the same kind of input on their own screens, through a digitizer layer in the display.
How it works
A sensor grid under the surface tracks the pen tip. A mouse or touchpad moves the pointer relative to where it was, but a graphics tablet uses absolute positioning: each point on the tablet maps to a fixed point on the screen, so touching the top-left corner of the pad puts the pointer in the top-left corner of the display. The pen also reports pressure, commonly with 2,048 to 8,192 levels, and often tilt, so lines get thicker or darker as you press harder. Buttons on the pen and tablet can be mapped to right-click, undo or other shortcuts.
Pen technologies
| Type | Power | Notes |
|---|---|---|
| EMR (electromagnetic resonance) | The tablet's electromagnetic field powers the pen; no battery | Used by Wacom tablets and Samsung S Pen devices |
| Active pen | Battery or rechargeable cell in the pen | Common on 2-in-1 laptops; some use Bluetooth only for the pen's shortcut buttons |
| Passive capacitive stylus | None; imitates a fingertip | Works on any capacitive touchscreen, with no pressure sensitivity |
Connection and drivers
Most graphics tablets connect by USB, which carries both data and power, and many also offer Bluetooth. Windows recognizes a tablet as a basic pointing device with a generic driver, but pressure sensitivity, button mapping and monitor mapping need the manufacturer's driver. If a tablet moves the pointer but lines show no pressure variation, install or update the vendor driver, then check the driver's Windows Ink option and the drawing application's tablet setting.
Troubleshooting
- Pen does not respond: dead battery (active pens), a worn nib, or the tablet driver service not running. Restart the service or reinstall the driver.
- Erratic behavior after switching brands: leftover drivers from another tablet maker conflict with the new one, so uninstall them.
- Pointer lands on the wrong monitor: set the display mapping in the tablet driver.
- Pointer offset from the pen tip on a pen display: run the calibration in the tablet driver, or in Windows use the pen and touch calibration in Tablet PC Settings.
Graphics tablet on the CompTIA A+ exam
Core 1 objective 1.2 lists "trackpad/drawing pad/track points" among mobile device accessories and connectivity options. Know what a drawing pad is used for, that it connects by USB or Bluetooth, that it needs the vendor driver for pressure and buttons, and that it uses absolute positioning while trackpads and track points move the pointer relatively. Do not confuse it with the digitizer in a touchscreen, which is the touch-sensing layer of a display covered in objective 3.1.