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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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38 ** $QT_END_LICENSE$ |
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40 ****************************************************************************/ |
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41 |
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42 /*! |
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43 \page qt-embedded-vnc.html |
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44 \brief A guide to using Qt for Embedded Linux applications as VNC servers |
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45 and clients. |
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46 |
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47 \title The VNC Protocol and Qt for Embedded Linux |
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48 \ingroup qt-embedded-linux |
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49 |
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50 VNC (Virtual Network Computing) software makes it possible to view |
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51 and interact with one computer (the "server") from any other |
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52 computer or mobile device (the "viewer") anywhere on a network. |
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53 |
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54 \image qt-embedded-vnc-screen.png |
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55 |
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56 VNC clients are available for a vast array of display systems, including |
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57 X11, Mac OS X and Windows. |
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58 |
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59 \section1 Configuring Qt with VNC Capabilities |
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60 |
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61 To run a \l{Qt for Embedded Linux} application using the VNC protocol, the |
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62 \l{Qt for Embedded Linux} library must be configured and compiled with the |
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63 \c -qt-gfx-vnc option: |
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64 |
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65 \snippet doc/src/snippets/code/doc_src_emb-vnc.qdoc 0 |
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66 |
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67 \section1 Running a Server Application |
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68 |
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69 Start a server application by specifying the \c -qws command |
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70 line option when running the application. (This can also be |
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71 specified in the application's source code.) |
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72 Use the \c -display command line option to specify the VNC server's |
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73 driver and the virtual screen to use. For example: |
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74 |
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75 \snippet doc/src/snippets/code/doc_src_emb-vnc.qdoc 1 |
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76 |
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77 The application will act as a VNC server which can be accessed using |
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78 an ordinary VNC client, either on the development machine or from a |
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79 different machine on a network. |
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80 |
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81 For example, using the X11 VNC client to view the application from the |
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82 same machine: |
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83 |
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84 \snippet doc/src/snippets/code/doc_src_emb-vnc.qdoc 2 |
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85 |
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86 To interact with the application from another machine on the network, |
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87 run a VNC client pointing to the machine that is running the server |
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88 application. |
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89 |
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90 \l{Qt for Embedded Linux} will create a 640 by 480 pixel display by |
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91 default. Alternatively, the \c QWS_SIZE environment variable can be |
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92 used to set another size; e.g., \c{QWS_SIZE=240x320}. |
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93 |
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94 \section1 Running Client Applications |
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95 |
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96 If you want to run more than one application on the same display, you |
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97 only need to start the first one as a server application, using the |
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98 \c -qws command line option to indicate that it will manage other |
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99 windows. |
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100 |
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101 \snippet doc/src/snippets/code/doc_src_emb-vnc.qdoc Starting server |
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102 |
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103 Subsequent client applications can be started \e without the \c -qws |
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104 option, but will each require the same \c -display option and argument |
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105 as those used for the server. |
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106 |
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107 \snippet doc/src/snippets/code/doc_src_emb-vnc.qdoc Starting clients |
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108 |
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109 However, for the clients, this option will not cause a new VNC server |
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110 to be started, but only indicates that their windows will appear on the |
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111 virtual screen managed by the server application. |
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112 |
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113 \section1 Related Resources |
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114 |
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115 It is not always necessary to specify the \c -qws command line option |
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116 when running a server application as long as the QApplication object |
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117 used by the application has been constructed with the |
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118 QApplication::GuiServer flag. |
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119 |
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120 See the \l{Running Qt for Embedded Linux Applications}{running applications} |
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121 documentation for more details about server and client applications. |
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122 |
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123 \table |
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124 \row |
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125 \o \bold {The Virtual Framebuffer} |
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126 |
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127 The \l{The Virtual Framebuffer}{virtual framebuffer} is |
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128 an alternative technique recommended for development and debugging |
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129 purposes. |
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130 |
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131 The virtual framebuffer emulates a framebuffer using a shared |
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132 memory region and the \c qvfb tool to display the framebuffer in a |
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133 window. |
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134 |
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135 Its use of shared memory makes the virtual framebuffer much faster |
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136 and smoother than using the VNC protocol, but it does not operate |
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137 over a network. |
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138 |
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139 \o \inlineimage qt-embedded-virtualframebuffer.png |
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140 \endtable |
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141 */ |