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<concept id="GUID-9126A296-0301-4077-A183-3D703F77C548" xml:lang="en">
<title>Support for Multiple Pointers in the Emulator Overview</title>
<shortdesc>This topic provides an overview of support for multiple
pointers 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></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"></image></fig>
<p>The delivery of pointer events from the emulator driver to the
Window Server is the same when there are multiple pointers 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 < 0 indicates the proximity of the device from the screen.</p
></li>
<li><p>Z > 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 Multiple
Pointers in the Emulator Tutorial</xref> for more information.</p
></li>
<li><p>When the Z value is in the pressure range (Z > 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 < 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 Multiple Pointers <?Pub Caret?>in the Emulator Tutorial</linktext>
</link>
</related-links>
</concept>
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