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<concept id="GUID-9126A296-0301-4077-A183-3D703F77C548" xml:lang="en"><title>Multi-Touch
Support in the Emulator Overview</title><shortdesc>This topic provides an overview of multi-touch support in the emulator.
Two mice are used to provide two independent pointer positions. The emulator
responds to the mice’s individual button-clicks, moves, and mouse wheel scrolls
as if two human fingers are moving, touching or hovering over the screen.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>The emulator can be extended to support more than two mice or other pointer
devices.</p>
<p><b>Variant</b>: <xref href="GUID-D93978BE-11A3-5CE3-B110-1DEAA5AD566C.dita">ScreenPlay</xref>. <b>Target
audience</b>: Application developers. </p>
<p>The following figure shows two Windows pointers on the emulator screen,
each representing a mouse device. The ordinal integer (starting from 0) beside
each pointer is the unique device identifier. The position of each mouse on
the screen is represented by the X and Y coordinates. The pressure (a positive
value) and proximity (a negative value) information captured by the mouse
wheel is represented by the Z coordinate. Notice that the status bar shows
the identifier and the dynamic X, Y and Z values of each pointer.</p>
<fig id="GUID-03428614-06B1-4821-A284-C3B6DB8E053C">
<title>Two pointers are displayed in the emulator</title>
<image href="GUID-3E80A006-F8D8-45C5-9773-7CC239AE86D9_d0e194049_href.png" placement="inline"/>
</fig>
<p>The delivery of pointer events from the emulator driver to the Window Server
is the same in the multi-touch environment as in the single pointer environment.
This means the raw events for a mouse move, button click and mouse wheel movement
are delivered to the Window Server as usual. Each mouse has a unique device
identifier, which makes it possible to ascertain which mouse the events relate
to. The raw events for each individual mouse include the following: </p>
<ul>
<li><p><codeph>TRawEvent::EPointerMove</codeph> indicates a mouse move or
a mouse wheel movement event.</p></li>
<li><p><codeph>TRawEvent::EButton1Down</codeph> indicates that the left mouse
button is pressed down.</p></li>
<li><p><codeph>TRawEvent::EButton1Up</codeph> indicates that the left mouse
button is released.</p></li>
<li><p><codeph>TRawEvent::EPointerOutOfRange</codeph> indicates that the proximity
of a mouse is out of range. This means that the Z coordinate value of the
mouse has reached <codeph>HALData::EPointer3DMaxProximity</codeph>.</p></li>
</ul>
<section id="GUID-44C3561D-92A1-421E-9AD3-0D8648919C46-GENID-1-10-1-12-1-1-7-1-6-1-6-1-9-1-9-1-8-1-5-1-3-7">       <title>Pressure
and proximity emulation</title><p>The Z coordinate value is used to represent
the pressure and proximity to the screen. In the emulator, the Z value is
captured and tuned by the mouse wheel movement.</p><ul>
<li><p>Z &lt; 0 indicates the proximity of the device from the screen.</p></li>
<li><p>Z &gt; 0 indicates pressure.</p></li>
</ul><p>See <xref href="GUID-9C269F45-F160-5A4B-ABF8-896D2A538E3B.dita">Advanced
Pointer Overview</xref> for more information about pressure and proximity.</p><p>The
mouse wheel combines the features of a wheel and a mouse button. The wheel
has discrete, evenly spaced notches. Rotating the wheel backwards or forwards
has the effect of changing the pressure or proximity.</p><ul>
<li><p>When the mouse wheel is rotated, a device-specific message is sent
to the emulator window that has focus as each notch is encountered.</p></li>
<li><p>The Z coordinate is initiated as 0. Then when the wheel is moved forward,
the Z value enters the pressure range and increases by one pressure step.
When the wheel is moved backward, the Z value enters the proximity range and
decreases by one proximity step.</p><p>The pressure or proximity step can
be customized in the <filepath>epoc.ini</filepath> file. See <xref href="GUID-930F1E88-2A03-4BD1-AA2A-3A0128A844BD.dita">Enabling
Multi-Touch in the Emulator Tutorial</xref> for more information.</p></li>
<li><p>When the Z value is in the pressure range (Z &gt; 0), moving the wheel
forward by one notch increases Z by one pressure step. Moving the wheel backward
by one notch decreases Z by one pressure step, until Z returns to 0.</p></li>
<li><p>When the Z value is in the proximity range (Z &lt; 0), moving the wheel
backward by one notch decreases Z by one proximity step. Moving the wheel
forward by one notch increases Z by one proximity step, until Z returns to
0. </p></li>
<li><p>There are limits to the values of the Z coordinate. This
means that the Symbian emulator does not allow Z to exceed the upper boundary <xref href="GUID-8BE90160-2C60-3582-82C8-4A108C7C0317.dita#GUID-8BE90160-2C60-3582-82C8-4A108C7C0317/GUID-BF464EF0-D685-3B12-9E13-65A86BAED610"><apiname>HALData::EPointer3DMaxPressure</apiname></xref> (a
positive value) and lower boundary <xref href="GUID-8BE90160-2C60-3582-82C8-4A108C7C0317.dita#GUID-8BE90160-2C60-3582-82C8-4A108C7C0317/GUID-7FCDA198-1E26-3BC9-A5A1-C4AF67016615"><apiname>HALData::EPointer3DMaxProximity</apiname></xref> (a
negative value).  If Z is at the lower boundary, when the mouse wheel is moved
backward next time, Z does not change. A new <codeph>Out of Range</codeph> pointer
event is generated and sent to the Window Server. Similarly when Z is at the
upper boundary, Z does not change when the mouse wheel is moved forward.</p></li>
<li><p>When the mouse button down or up event (<codeph>TRawEvent::EButton1Down</codeph> or <codeph>TRawEvent::EButton1Up</codeph>)
is generated, Z is reset to 0.</p></li>
</ul>     </section>
</conbody><related-links>
<link href="GUID-A12A66ED-2C8F-5CE6-8F3E-332B045A35B4.dita"><linktext>Advanced
Pointers</linktext></link>
<link href="GUID-930F1E88-2A03-4BD1-AA2A-3A0128A844BD.dita"><linktext>Enabling
Multi-Touch in the Emulator Tutorial</linktext></link>
</related-links></concept>