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Touch Screen Calibration (WinCE)

This article will explain how to do touch screen calibration in WinCE.

Touch Screen Calibration using Control Panel​

  • Click on Start->Settings->Control Panel->Stylus->Calibration->Recalibrate.
  • Calibrate the five point accurately.
  • Press ENTER if keyboard is connected else TAP on the screen, it will exit the calibration screen.
  • Save registry from Start->Programs->ColibriTools->SaveReg.

Touch Screen Calibration from code​

BOOL WINAPI TouchCalibrate(void) function is used to calibrate touch screen in WinCE.

For more information visit msdn

C/C++

int wmain()
{
    TouchCalibrate();
    if( ERROR_SUCCESS != RegFlushKey( HKEY_LOCAL_MACHINE))
        RETAILMSG( 1, (TEXT("Save Key failed (%d)\n"), GetLastError() ));
    return 0;
}

Visual C#

using System;
using System.Linq;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;                     //To use C Win32 functions
    
namespace CSharp_TouchScreen_Calibration
{
    public partial class Form1 : Form
    {
        [DllImport("coredll")]
        private static extern bool TouchCalibrate();      //import function from coredll
        
        [DllImport("coredll.dll", EntryPoint = "RegFlushKey", SetLastError = true)]
        public static extern uint RegFlushKey(uint hKey); //import function from coredll
        
        const uint HKEY_LOCAL_MACHINE = 0x80000002;
        
        public Form1()
        {
            InitializeComponent();
            touchCalibrate();// function will be called on Form Load
        }

        public void touchCalibrate()
        {
            TouchCalibrate();
            RegFlushKey(HKEY_LOCAL_MACHINE);
        }
    }
}

Note: To save registry from code use RegFlushKey function.

Troubleshooting: Calibration Process Repeats Forever​

If the touchscreen calibration values are outside the required quality (after touching the 5 points on the screen), the calibration is rejected, and the process starts over. This is typically a sign of too much noise on the analog signals, or inadequate timing settings of the touch measurement process.

The suggested measures are:

  1. Refer to the separate page about touch screen registry settings in order to optimize the measurement settings for your touch screen
  2. To overrule the touch calibration process, and allow for a wider quality span, add the following registry settings:
[HKEY_LOCAL_MACHINE\Hardware\DEVICEMAP\Touch]
"MaxCalError" = DWORD:100


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