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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-552530EB-1287-542D-AED3-125387B485C1" xml:lang="en"><title>Architecture</title><shortdesc>Describes the architecture of the Digitizer Driver. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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13 <p>The architecture has two layers: </p> |
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14 <table id="GUID-66F9A575-14A6-5F98-9166-CF5F5B03BF67"> |
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15 <tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/> |
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16 <tbody> |
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17 <row> |
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18 <entry><p>A platform-independent layer that: </p> </entry> |
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19 <entry><ul> |
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20 <li id="GUID-1F3AAAB4-181C-54EF-83AA-CEBE00590934"><p>processes digitiser |
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21 samples </p> </li> |
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22 <li id="GUID-F8D8BC65-0D80-5D5A-9F87-B8C34FEE70A2"><p>issues pen movement |
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23 events to the kernel </p> </li> |
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24 <li id="GUID-75A10183-BFCE-5D3D-B167-6D884EED335F"><p>maintains a buffer of |
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25 digitiser readings </p> </li> |
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26 </ul> <p>This layer implements behaviour that can be expected to be the same |
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27 across all platforms. </p> <p> <i>Symbian provides this.</i> </p> </entry> |
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28 </row> |
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29 <row> |
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30 <entry><p>A platform specific layer that is responsible for: </p> </entry> |
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31 <entry><ul> |
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32 <li id="GUID-5D268750-7FF8-527F-B670-02A2605F610E"><p>the conversion between |
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33 screen and digitiser coordinates </p> </li> |
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34 <li id="GUID-65D85059-ED68-5AEF-BA1C-8255D5AAADC1"><p>the implementation of |
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35 low level calibration </p> </li> |
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36 <li id="GUID-98D55CC6-946B-5396-A518-65AF137684D3"><p>the gathering of raw |
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37 digitiser data samples </p> </li> |
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38 <li id="GUID-6E3D68AF-4EF8-50CA-90EA-814820C15ACA"><p>power management. </p> </li> |
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39 </ul> <p>This layer implements behaviour that can vary between platforms and |
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40 therefore needs to be implemented by the port. </p> <p>The bulk of the effort |
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41 here is the definition and implementation of a class derived from the Symbian |
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42 defined <xref href="GUID-2EDAF642-2399-3594-986A-5E8A5EEA01B9.dita"><apiname>DDigitiser</apiname></xref> class; the derived class implements |
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43 the pure virtual functions defined by <codeph>DDigitiser</codeph>. </p> <p> <i>You |
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44 provide this.</i> </p> </entry> |
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45 </row> |
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46 </tbody> |
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47 </tgroup> |
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48 </table> |
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49 <p>The template port provides a framework for implementing the platform specific |
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50 part of the digitiser. The diagram below shows the overall relationship: </p> |
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51 <fig id="GUID-25F301AD-9B05-51BF-A96B-C99AB5B2D2E4"> |
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52 <image href="GUID-904C9C5A-5FDB-5978-88CF-E30D6C0DBB61_d0e8869_href.png" placement="inline"/> |
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53 </fig> |
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54 <p>The standard Symbian platform ports all follow the same general pattern, |
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55 including the H2. However, the H2 board implementation has two levels in its |
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56 platform specific layer (an ASSP and a variant layer) and uses different source |
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57 file names (e.g. <filepath>digitizer.cpp</filepath>), but, nevertheless, the |
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58 same general pattern applies. </p> |
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59 </conbody></concept> |