Thursday, July 17, 2014

GTViewer and GTVx with Touch Screens

With Windows 8 and 8.1 machines becoming more widespread, the availability of a Touch Screen is common .  It is also possible to use Windows 7 with a Touch Screen too, so the chances of using GTViewer with a Touch Screen is more and more likely.

Version 14.0.x.21 of GTViewer and 14.0.x.7 of GTVx both provide specific settings to make them run better with a Touch Screen interface.   They have always worked with Windows 8 and 8.1 using conventional inputs (mouse and keyboard), but the scrollbars on the map view window seem to confuse the Touch Screen interface.

In GTViewer, you can now use the Options/Settings dialog to configure 4 different setting values to better use a Touch Screen interface:


  1. Change View Scrollbars to NO.
  2. Change the Mouse Wheel Increment to a negative value.   This will make a 2 finger pinch gesture zoom out instead of zoom in.
  3. Change the Toolbar Button Size to Large, Larger, or Largest.  Making the buttons larger, makes them easier to use with touch.
  4. You may also want to set the Selection Tolerance to a higher value since touch is not as accurate as a mouse click.


The View Scrollbars and Toolbar Button Size settings are new to 14.0.x.21.   Mouse Wheel Increment and Selection Tolerance were already available, and you must use the Set as Default button to retain the value beyond the current session.


In GTVx, you can use the following to set the setting values:

   AxGTVX1.ShowScrollBars(0)
   AxGTVX1.SetDataProperty("MouseWheelIncrement", "-1.5")
   AxGTVX1.SetDataProperty("SelectionTolerance", "6")

Make sure to call the ShowScrollBars method before you open any data.


With these settings, you should be able to use a Pinch to zoom in or out in any mode that you can use the moue wheel to zoom in or out.  

A Touch should behave like a mouse click in most GTViewer modes, and Touch and Hold will activate a right mouse click.


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