NextWindow Two-Touch API
NextWindow's touch Application Program Interface (API) provides programmers
with access to touch data generated by a NextWindow touch screen. It
also provides derived touch information.
The touch events, data and derived information can be used in any way the
application wants.
Communications are via HID-compliant USB.
The API is in the form of a DLL that provides useful functions for
application developers.
Multi-Touch
Multi-touch simply refers to a touch-sensitive device that can independently
detect and optionally resolve the position of two or more touches on screen at
the same time. In contrast, a traditional touch screen senses the position of a
single touch and hence is not a multi-touch device.
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“Detect” refers to the ability to sense
that a touch has occurred somewhere on screen. |
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“Resolve” refers to the ability to report
the coordinates of the touch position. |
NextWindow’s standard optical touch hardware can detect two touches on
screen. The firmware can resolve the position of two simultaneous touches (with
some limitations).
Demonstration Two-Touch Application
This small application demonstrates using touch to move and manipulate
pictures on a screen. It runs on a PC with any NextWindow USB touch screen. The
touch screen must be the primary monitor, correctly connected to the PC and calibrated for the size
of screen.
The following operations are available.
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Use one finger to move a picture. |
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Use a finger from each hand to move two
pictures independently. |
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Touch and drag close to the edge of a
picture to
rotate it. You can rotate two pictures at the same time. |
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Use finger and thumb of one hand (or a
finger from each hand) in a stretching, squeezing or rotating action on any of the pictures. |
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Flick a picture in any direction to send it
flying across the screen. You can touch the moving picture to capture it
again. |
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Press [R] on the keyboard at any time to
reset the background to the start position. |
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Press [Esc] to quit the program. |
You can insert your own pictures into the program by simply copying them into
the "image" directory (normally C:\Program files\NextWindow\NextWindow
PhotoTable\image. The following graphics formats are supported: bmp, jpg,
gif, png, jpeg, and tiff.
Download NextWindow PhotoTable Demo Program
To run NextWindow's PhotoTable two-touch demonstration program, download and
run the install program,
NextWindowPhotoTableSetup.msi.
Two-Touch Demo Program - Notes
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The program automatically puts the touch screen into multi-touch mode. The mode can be viewed / changed using USB Config,
which is part of the Touch+
suite of utility programs.
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The speed of scaling depends on the initial distance between the two
touches. So, for example, if you touch the screen with finger and
thumb close together and then move apart, the speed of scaling the
picture will be fast. Conversely, if you start with two fingers far
apart, the speed of scaling will be slow. |
NextWindow Multi-Touch API Downloads
NWMultiTouchAPI.zip contains the following files:
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NWMultiTouch.dll |
The DLL file containing the Multi-Touch
API. |
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NWMultiTouch.h |
The Header file containing the function
definitions. |
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NWMultiTouchMS.lib |
The Library file for Microsoft Visual
Studio compiler |
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NWMultiTouch.lib |
The Library file for Borland and other
compilers |
Example Code
NWMultiTouchCSharpSample.zip
NWMultiTouchCPlusPlusSample.zip
Documentation
NextWindow USB API
User Guide (153 KB pdf file)
NextWindow
Multi-Touch Whitepaper (2722 KB pdf)
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