Touchscreen Calibration

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Certain user input devices such as touchscreens needs to be calibrated. For this, the GINPUT module provides a calibration dialog. The calibration uses a tree-point algorithm. Three calibration points (cross hairs) will show up, one after another. Each of the crosses needs to be pressed as precisely as possible. At the end a fourth calibration cross will appear in the center of the screen. This last calibration point is used to test whether the calibration was successful. If the difference between the internal read-out of the touch coordinate and the expected result is too big the process will be restarted automatically. See Tolerance for more information.

Tolerance

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Extreme coordinates

By default the cross-hairs of the calibration dialog will show with about 25% distance to the display border. However, for some touchscreen types it is better to place the calibration cross-hairs directly at the corners of the display. To enable this feature GINPUT_MOUSE_MAX_CALIBRATION_ERROR may be set to TRUE in the touchscreen drivers board file.