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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-9AD75103-CD56-5279-B639-5CA2BBF979B5" xml:lang="en"><title>Advanced |
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13 Pointer States and Event Communication</title><shortdesc>The Window Server provides advanced pointer features, such as support |
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14 for multiple pointers and proximity and pressure coordinates. This topic provides |
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15 a summary of advanced pointer states and the events that communicate changes |
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16 of their state. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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17 <p> <b>Variant</b>: <xref href="GUID-D93978BE-11A3-5CE3-B110-1DEAA5AD566C.dita">ScreenPlay</xref>. <b>Target |
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18 audience</b>: Application developers. </p> |
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19 <p>This topic builds on the <xref href="GUID-9C269F45-F160-5A4B-ABF8-896D2A538E3B.dita">Advanced |
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20 Pointer Overview</xref>. </p> |
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21 <section id="GUID-4B7318D7-29AB-4DE4-B37A-2AFAE055982E"><title>Communication |
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22 between an input driver and the Window Server</title> <p>The following diagram |
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23 shows how an input driver communicates changes in pointer state to the Window |
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24 Server. The diagram shows the logical pointer states and how <xref href="GUID-668CEA36-3933-3BBE-A980-CAB62617B4FD.dita"><apiname>TRawEvent</apiname></xref> types |
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25 change those states. From the driver's perspective, the pointer can be in |
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26 one of three basic logical states: <i>Up</i>, <i>Down</i> or <i>OutOfRange</i>. </p> <p>The |
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27 driver sends a number of types of event to move the pointer between these |
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28 states. For example, <xref href="GUID-0FD31DF6-3EA2-3EB3-8940-05F187B98B86.dita"><apiname>EButton1Up</apiname></xref> is an <i>Up</i> event that |
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29 changes the pointer from the <i>Down</i> to the <i>Up</i> state. <xref href="GUID-2786B13B-B95C-3D15-B7D2-205E99A64FBC.dita"><apiname>EButton1Down</apiname></xref> is |
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30 a <i>Down</i> event. <codeph>EButton1Down</codeph> changes the pointer from |
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31 the <i>Up</i> to the <i>Down</i> state, and from <i>OutOfRange</i> to the <i>Down</i> state. </p> <p>There |
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32 can be any number of pointers, and each pointer has a maximum of three buttons. |
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33 A platform UI is free to implement buttons in any way. However, the Window |
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34 Server interprets only Button1 as an <b>action</b> and does not interpret |
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35 the other buttons. </p> <fig id="GUID-2664573F-C5E8-573F-9427-783074351585"> |
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36 <title> Driver communicates pointer state changes to the Window Server |
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37 </title> |
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38 <image href="GUID-35521A99-3F1F-5EE1-8078-FFD8A298C0BD_d0e197572_href.png" placement="inline"/> |
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39 </fig> <p>For a complete list of pointer states, the events that can be sent |
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40 by the driver, and the associated events that the Window Server sends to the |
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41 client, see the <xref href="GUID-9AD75103-CD56-5279-B639-5CA2BBF979B5.dita#GUID-9AD75103-CD56-5279-B639-5CA2BBF979B5/GUID-EC2B9C82-D678-5DFE-89A8-8CFCF5376244">Pointer |
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42 states and event communication</xref> table below. </p> </section> |
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43 <section id="GUID-3698CDAC-A904-5C44-BFD1-669D9673D02B"><title> Pointer states</title> <p>Pointing |
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44 devices can be in one of the following basic states: </p> <table id="GUID-5255E70E-EF7C-5AA6-9F94-AF720B5B805F"> |
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45 <tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/> |
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46 <thead> |
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47 <row> |
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48 <entry>State</entry> |
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49 <entry>Description</entry> |
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50 </row> |
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51 </thead> |
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52 <tbody> |
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53 <row> |
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54 <entry><p> <b>Out of range</b> </p> </entry> |
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55 <entry><p>Not detected by the device's sensors. </p> </entry> |
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56 </row> |
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57 <row> |
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58 <entry><p> <b>Up</b> </p> </entry> |
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59 <entry><p>Detected by sensors, coordinates available, not performing an action. </p> </entry> |
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60 </row> |
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61 <row> |
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62 <entry><p> <b>Down</b> </p> </entry> |
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63 <entry><p>Detected by sensors, coordinates available, performing an action |
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64 (as defined above). </p> </entry> |
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65 </row> |
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66 </tbody> |
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67 </tgroup> |
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68 </table> <p>The following diagram shows the extension of the <i>Up</i> and <i>Down</i> states |
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69 with additional substates. <i>Up</i> is extended with substates describing |
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70 the <b>closeness</b> of the pointer to the screen. <i>Down</i> is extended |
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71 with substates describing <b>pressing</b>. </p> <fig id="GUID-54DA3BEC-A650-5223-8E46-5B68F414A909"> |
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72 <title> Extension of Up and Down states with substates </title> |
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73 <image href="GUID-4E1D4E5D-7CE6-5A93-9170-BEF2937FC953_d0e197686_href.png" placement="inline"/> |
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74 </fig> <p>The Window Server generates the following events for changes of |
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75 closeness and pressing: </p> <ul> |
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76 <li id="GUID-72265325-882B-5B38-ABE7-EFDF05758B97"><p> <codeph>EExitCloseProximity</codeph> </p> </li> |
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77 <li id="GUID-D22BF039-8D17-53A4-83C1-3390EBDFBE46"><p> <codeph>EEnterCloseProximity</codeph> </p> </li> |
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78 <li id="GUID-5968A499-B87B-54D2-9926-EF446ED1BCCD"><p> <codeph>EExitHighPressure</codeph> </p> </li> |
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79 <li id="GUID-4FB8633D-29F1-5794-A922-65603035F23A"><p> <codeph>EEnterHighPressure</codeph> </p> </li> |
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80 </ul> <p>These are all types of <xref href="GUID-1FFA0073-3D83-388E-A824-08C31F90CC54.dita"><apiname>TPointerEvent</apiname></xref>. Because |
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81 these state changes depend on the pressure and proximity of the pointer, both |
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82 of these values are checked each time a new <xref href="GUID-668CEA36-3933-3BBE-A980-CAB62617B4FD.dita"><apiname>TRawEvent</apiname></xref> concerning |
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83 the pointer arrives from the driver. <xref href="GUID-668CEA36-3933-3BBE-A980-CAB62617B4FD.dita#GUID-668CEA36-3933-3BBE-A980-CAB62617B4FD/GUID-C7FB5C5F-B7E1-3738-B72D-1AD81699414F"><apiname>TRawEvent::EPointer3DOutOfRange</apiname></xref> means |
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84 that the proximity is infinite and pressure is zero. </p> <p>These events |
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85 are based on four thresholds: </p> <ul> |
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86 <li id="GUID-6B27FB3B-EFFE-5D25-B039-FA84F0BFCE66"><p>The <codeph>EExitHighPressure</codeph> threshold |
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87 (<codeph>EPointer3DExitHighPressureThreshold</codeph> in HAL) </p> <p>This |
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88 is a threshold on the pointer's Z coordinate. In general, if the pointer crosses |
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89 this threshold by decreasing pressure (thus decreasing its Z coordinate), |
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90 the Window Server generates <xref href="GUID-1FFA0073-3D83-388E-A824-08C31F90CC54.dita#GUID-1FFA0073-3D83-388E-A824-08C31F90CC54/GUID-9062D892-DE16-3F74-AC0D-76A7F047B52B"><apiname>TPointerEvent::EExitHighPressure</apiname></xref> and |
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91 sends it to the client. </p> </li> |
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92 <li id="GUID-6F8E2E38-59A5-5FF3-B332-5D68252749B9"><p>The <codeph>EEnterHighPressure</codeph> threshold |
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93 (<codeph>EPointer3DEnterHighPressureThreshold</codeph> in HAL) </p> <p>This |
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94 is a threshold on the pointer's Z coordinate. In general, if the pointer crosses |
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95 this threshold by increasing pressure (thus increasing its Z coordinate), |
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96 the Window Server generates <xref href="GUID-1FFA0073-3D83-388E-A824-08C31F90CC54.dita#GUID-1FFA0073-3D83-388E-A824-08C31F90CC54/GUID-39963088-400D-3F0B-B7B1-36064CE92A67"><apiname>TPointerEvent::EEnterHighPressure</apiname></xref> and |
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97 sends it to the client. </p> </li> |
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98 <li id="GUID-CB32D252-B1CD-56D4-A5CF-88E99C2BCDD8"><p>The <codeph>EEnterCloseProximity</codeph> threshold |
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99 (<codeph> EPointer3DEnterCloseProximityThreshold</codeph> in |
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100 HAL) </p> <p>This is a threshold on the pointer's Z coordinate. In general, |
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101 if the pointer crosses this threshold by decreasing its proximity from the |
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102 device (thus increasing its Z coordinate), the Window Server generates <xref href="GUID-1FFA0073-3D83-388E-A824-08C31F90CC54.dita#GUID-1FFA0073-3D83-388E-A824-08C31F90CC54/GUID-7BDBA988-0D3A-35B2-A5AE-FFA56CC48D12"><apiname>TPointerEvent::EEnterCloseProximity</apiname></xref> and |
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103 sends it to the client. </p> </li> |
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104 <li id="GUID-C60E937A-E786-55CE-BEEC-655E78B6ED41"><p>The <codeph>EExitCloseProximity</codeph> threshold |
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105 (<codeph>EPointer3DExitCloseProximityThreshold</codeph> in HAL) </p> <p>This |
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106 is a threshold on the pointer's Z coordinate. In general, if the pointer crosses |
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107 this threshold by increasing its proximity from the device (thus decreasing |
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108 its Z coordinate), the Window Server generates <xref href="GUID-1FFA0073-3D83-388E-A824-08C31F90CC54.dita#GUID-1FFA0073-3D83-388E-A824-08C31F90CC54/GUID-C9226074-F285-3934-83C1-5533485FE6A6"><apiname>TPointerEvent::EExitCloseProximity</apiname></xref> and |
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109 sends it to the client. </p> </li> |
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110 </ul> <p>Applications can configure these thresholds at runtime by using Window |
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111 Server APIs in <xref href="GUID-643DDA78-C7A7-386D-AB3F-8710141DDDA9.dita"><apiname>RWsSession</apiname></xref>. All applications can read these |
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112 thresholds. However, only code with <codeph>WriteDeviceData</codeph> capability |
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113 can change them because these changes should be made only by the device's |
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114 configuration application. </p> </section> |
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115 <section id="GUID-EC2B9C82-D678-5DFE-89A8-8CFCF5376244"><title>Pointer states |
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116 and event communication</title> <p>The table below shows all possible pointer |
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117 states. For each state it shows all of the events that can be sent by the |
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118 driver and all of the events that are sent by the Window Server to the client. |
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119 The end state of the pointer is also shown. There are five pointer zones (states) |
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120 and four thresholds. An event is generated when the pointer's z position crosses |
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121 a threshold. </p> <table id="GUID-630982B7-0367-558B-A1B0-B115EB7625A9"> |
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122 <tgroup cols="4"><colspec colname="col0"/><colspec colname="col1"/><colspec colname="col2"/><colspec colname="col3"/> |
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123 <thead> |
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124 <row> |
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125 <entry> Pointer state</entry> |
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126 <entry> <codeph>TRawEvent</codeph> received from driver</entry> |
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127 <entry> <codeph>TPointerEvent</codeph> sent by Window Server</entry> |
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128 <entry>Resulting pointer state</entry> |
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129 </row> |
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130 </thead> |
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131 <tbody> |
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132 <row> |
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133 <entry><p>OutOfRange </p> </entry> |
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134 <entry><p> <codeph>EPointer3DOutOfRange</codeph> </p> </entry> |
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135 <entry><p>— </p> </entry> |
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136 <entry><p> <codeph>EOutOfRange</codeph> </p> </entry> |
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137 </row> |
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138 <row> |
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139 <entry><p>OutOfRange </p> </entry> |
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140 <entry><p> <codeph>EMove</codeph> (Z < <codeph>EEnterCloseProximity</codeph> threshold) </p> </entry> |
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141 <entry><p> <codeph>EMove</codeph> </p> </entry> |
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142 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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143 </row> |
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144 <row> |
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145 <entry><p>OutOfRange </p> </entry> |
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146 <entry><p> <codeph> EMove</codeph> (Z >= <codeph>EEnterCloseProximity</codeph> threshold) </p> </entry> |
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147 <entry><p> <codeph>EEnterCloseProximity</codeph> </p> </entry> |
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148 <entry><p>Up/InCloseProximity </p> </entry> |
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149 </row> |
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150 <row> |
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151 <entry><p>OutOfRange </p> </entry> |
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152 <entry><p> <codeph>EButton1Down</codeph> (Z < <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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153 <entry><p> <codeph>EButton1Down</codeph> </p> </entry> |
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154 <entry><p>Down/NotPressing </p> </entry> |
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155 </row> |
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156 <row> |
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157 <entry><p>OutOfRange </p> </entry> |
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158 <entry><p> <codeph> EButton1Down</codeph> (Z >= <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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159 <entry><p> <codeph>EButton1Down</codeph>, <codeph>EEnterHighPressure</codeph> </p> </entry> |
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160 <entry><p>Down/Pressing </p> </entry> |
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161 </row> |
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162 <row> |
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163 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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164 <entry><p> <codeph>EPointer3DOutOfRange</codeph> </p> </entry> |
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165 <entry><p> <codeph>EOutOfRange</codeph> </p> </entry> |
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166 <entry><p>OutOfRange </p> </entry> |
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167 </row> |
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168 <row> |
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169 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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170 <entry><p> <codeph>EMove</codeph> (Z < <codeph>EEnterCloseProximity</codeph> threshold) </p> </entry> |
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171 <entry><p> <codeph>EMove</codeph> </p> </entry> |
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172 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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173 </row> |
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174 <row> |
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175 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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176 <entry><p> <codeph>EMove</codeph> (Z >= <codeph>EEnterCloseProximity</codeph> threshold) </p> </entry> |
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177 <entry><p> <codeph>EEnterCloseProximity</codeph> </p> </entry> |
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178 <entry><p>Up/InCloseProximity </p> </entry> |
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179 </row> |
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180 <row> |
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181 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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182 <entry><p> <codeph>EButton1Down</codeph> (Z < <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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183 <entry><p> <codeph>EButton1Down</codeph> </p> </entry> |
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184 <entry><p>Down/OutOfHighPressure </p> </entry> |
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185 </row> |
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186 <row> |
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187 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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188 <entry><p> <codeph>EButton1Down</codeph> (Z >= <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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189 <entry><p> <codeph>EButton1Down</codeph>, <codeph>EEnterHighPressure</codeph> </p> </entry> |
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190 <entry><p>Down/InHighPressure </p> </entry> |
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191 </row> |
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192 <row> |
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193 <entry><p>Up/InCloseProximity </p> </entry> |
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194 <entry><p> <codeph>EPointer3DOutOfRange</codeph> </p> </entry> |
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195 <entry><p> <codeph>EOutOfRange</codeph> </p> </entry> |
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196 <entry><p>OutOfRange </p> </entry> |
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197 </row> |
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198 <row> |
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199 <entry><p>Up/InCloseProximity </p> </entry> |
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200 <entry><p> <codeph>EMove</codeph> (Z < <codeph>EExitCloseProximity</codeph> threshold) </p> </entry> |
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201 <entry><p> <codeph>EExitCloseProximity</codeph> </p> </entry> |
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202 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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203 </row> |
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204 <row> |
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205 <entry><p>Up/InCloseProximity </p> </entry> |
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206 <entry><p> <codeph>EMove</codeph> (Z >= <codeph>EExitCloseProximity</codeph> threshold) </p> </entry> |
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207 <entry><p> <codeph>EMove</codeph> </p> </entry> |
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208 <entry><p>Up/InCloseProximity </p> </entry> |
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209 </row> |
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210 <row> |
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211 <entry><p>Up/InCloseProximity </p> </entry> |
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212 <entry><p> <codeph>EButton1Down</codeph> (Z < <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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213 <entry><p> <codeph>EButton1Down</codeph> </p> </entry> |
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214 <entry><p>Down/OutOfHighPressure </p> </entry> |
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215 </row> |
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216 <row> |
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217 <entry><p>Up/InCloseProximity </p> </entry> |
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218 <entry><p> <codeph>EButton1Down</codeph> (Z >= <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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219 <entry><p> <codeph>EButton1Down</codeph>, <codeph>EEnterHighPressure</codeph> </p> </entry> |
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220 <entry><p>Down/InHighPressure </p> </entry> |
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221 </row> |
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222 <row> |
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223 <entry><p>Down/OutOfHighPressure </p> </entry> |
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224 <entry><p> <codeph>EButton1Up</codeph> (Z < <codeph>EExitCloseProximity</codeph> threshold) </p> </entry> |
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225 <entry><p> <codeph>EButton1Up</codeph>, <codeph>EExitCloseProximity</codeph> </p> </entry> |
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226 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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227 </row> |
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228 <row> |
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229 <entry><p>Down/OutOfHighPressure </p> </entry> |
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230 <entry><p> <codeph>EButton1Up</codeph> (Z >= <codeph>EExitCloseProximity</codeph> threshold) </p> </entry> |
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231 <entry><p> <codeph>EButton1Up</codeph> </p> </entry> |
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232 <entry><p>Up/InCloseProximity </p> </entry> |
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233 </row> |
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234 <row> |
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235 <entry><p>Down/OutOfHighPressure </p> </entry> |
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236 <entry><p> <codeph>EMove</codeph> (Z < <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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237 <entry><p> <codeph>EDrag</codeph> </p> </entry> |
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238 <entry><p>Down/OutOfHighPressure </p> </entry> |
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239 </row> |
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240 <row> |
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241 <entry><p>Down/OutOfHighPressure </p> </entry> |
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242 <entry><p> <codeph>EMove</codeph> (Z >= <codeph>EEnterHighPressure</codeph> threshold) </p> </entry> |
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243 <entry><p> <codeph>EEnterHighPressure</codeph> </p> </entry> |
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244 <entry><p>Down/InHighPressure </p> </entry> |
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245 </row> |
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246 <row> |
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247 <entry><p>Down/InHighPressure </p> </entry> |
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248 <entry><p> <codeph>EButton1Up</codeph> (Z < <codeph>EExitCloseProximity</codeph> threshold) </p> </entry> |
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249 <entry><p> <codeph>EButton1Up</codeph>, <codeph>EExitCloseProximity</codeph> </p> </entry> |
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250 <entry><p>Up/OutOfCloseProximity </p> </entry> |
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251 </row> |
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252 <row> |
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253 <entry><p>Down/InHighPressure </p> </entry> |
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254 <entry><p> <codeph>EButton1Up</codeph> (Z >= <codeph>EExitCloseProximity</codeph> threshold) </p> </entry> |
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255 <entry><p> <codeph>EButton1Up</codeph> </p> </entry> |
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256 <entry><p>Up/InCloseProximity </p> </entry> |
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257 </row> |
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258 <row> |
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259 <entry><p>Down/InHighPressure </p> </entry> |
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260 <entry><p> <codeph>EMove</codeph> (Z < <codeph>EExitHighPressure</codeph> threshold) </p> </entry> |
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261 <entry><p> <codeph>EExitHighPressure</codeph> </p> </entry> |
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262 <entry><p>Down/OutOfHighPressure </p> </entry> |
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263 </row> |
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264 <row> |
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265 <entry><p>Down/InHighPressure </p> </entry> |
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266 <entry><p> <codeph>EMove</codeph> (Z >= <codeph>EExitHighPressure</codeph> threshold) </p> </entry> |
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267 <entry><p> <codeph>EDrag</codeph> </p> </entry> |
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268 <entry><p>Down/InHighPressure </p> </entry> |
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269 </row> |
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270 </tbody> |
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271 </tgroup> |
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272 </table> <p>The driver is prohibited from sending <codeph>EPointer3DOutOfRange</codeph> when |
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273 the pointer is in the Down state. Therefore this is not included in this table. |
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274 Because <codeph>TRawEvent</codeph>'s <codeph>EPointer3DOutOfRange</codeph> events |
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275 do not have coordinates, the Window Server makes sure the event is delivered |
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276 to the place where the previous event for the same pointer occurred. It does |
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277 this by maintaining the last state of the pointer. </p> <p>The following diagram |
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278 shows the events sent from the Window Server to the client while |
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279 the pointer traverses the full cycle of events—from OutOfRange, through Down/InHighPressure |
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280 and back to OutOfRange. This diagram does not show all of the possible state |
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281 transitions that are described in the table above. </p> <fig id="GUID-C39B447C-0908-5F9A-95EC-2F97E56E2C20"> |
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282 <title> Events sent from Window Server to client while the pointer traverses |
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283 the full cycle of states. </title> |
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284 <image href="GUID-8F4C626F-3490-50BC-A97F-FD1972FFF65B_d0e198639_href.png" placement="inline"/> |
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285 </fig> </section> |
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286 </conbody><related-links> |
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287 <link href="GUID-9C269F45-F160-5A4B-ABF8-896D2A538E3B.dita"><linktext>Advanced |
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288 Pointer Overview</linktext></link> |
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289 <link href="GUID-C60DC070-572B-5960-B394-550426FDB909.dita"><linktext>Advanced |
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290 Pointer Tutorial</linktext></link> |
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291 </related-links></concept> |