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1 /* |
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2 * Copyright (c) 2003 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: SVG Engine header file |
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15 * |
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16 */ |
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17 |
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18 |
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19 #ifndef __INC_MSVGREQUESTOBSERVER__ |
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20 #define __INC_MSVGREQUESTOBSERVER__ |
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21 |
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22 |
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23 class CSvgElementImpl; |
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24 |
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25 |
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26 /** |
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27 * This interface is the callback mechanism for the SVG Engine to communicate to |
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28 * interested clients and to request for external data, such as images. |
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29 * The callbacks will be active when the methods of this interace are implemented and |
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30 * the pointer to the implementation object is passed in as the second parameter |
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31 * of the 'ConstructL' method of the CSvgEngineInterface. A 'null' value may be |
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32 * passed-in if the callbacks are to be ignored. |
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33 * |
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34 * @lib SVGEngine.lib |
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35 * @since 1.0 |
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36 */ |
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37 class MSvgRequestObserver |
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38 { |
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39 public: |
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40 |
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41 /** |
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42 * This method is called by the SVG Engine when all data for a certain |
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43 * step, such as animation frame, have been updated. This usually means |
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44 * the off-screen image (passed in to 'ConstructL' of CSvgEngineInterface) |
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45 * has been updated. The client usually redraws the image onto |
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46 * the screen. |
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47 * |
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48 * @since 1.0 |
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49 * @param : none |
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50 * @return : none |
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51 */ |
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52 virtual void UpdateScreen() = 0; |
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53 |
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54 /** |
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55 * This method is for future extension, in which an external script engine |
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56 * could be used to evaluate a script description. |
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57 * |
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58 * @since 1.0 |
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59 * @param : aScript -- A description of script from the "on" attribute. |
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60 * |
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61 * @param : aCallerElement -- The element that calls the script by a |
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62 * an event of the "on" attribute. |
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63 * @return : For future use. Value is ignored. |
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64 */ |
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65 virtual TBool ScriptCall( const TDesC& aScript, |
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66 CSvgElementImpl* aCallerElement ) = 0; |
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67 |
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68 /** |
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69 * This method is called to retrieve the file handle of an image name. |
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70 * The session (RFs) object passed in is guaranteed to be connected, so |
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71 * the client must NOT call aSession.Connect(). |
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72 * |
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73 * The implementation for the client of this method is usually if not always: |
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74 * TInt X::FetchImage( const TDesC& aFilename, RFs& aSession, RFile& aFileHandle ) |
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75 * { |
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76 * // Check for "http", get data from remote site, save to disk |
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77 * // Get absolute path to aFilename: absolutepath |
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78 * return aFileHandle.Open( aSession, absolutepath, EFileRead ); |
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79 * } |
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80 * |
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81 * Note: Use EFileShareReadersOnly to prevent file locking. |
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82 * |
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83 * The API AssignImageData() can be used to avoid block the parsing |
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84 * thread due this method taking too long to return. This is |
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85 * accomplished by returning a non-KErrNone value (i.e. KErrNotFound), |
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86 * and storing the URI parameter. The image data then could be |
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87 * assigned the the URI in another thread/Active-Object. |
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88 * |
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89 * @since 1.0 |
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90 * @param : aUri -- the relative path of an image file. |
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91 * @param : aSession -- File session used by client to open file. |
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92 * @param : aFileHandle -- File handle used by client to open file. |
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93 * @return : KErrNone if Open command successful, otherwise error-code |
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94 * from Open command. The SVG engine will proceed loading the file |
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95 * only if the return value is KErrNone. |
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96 */ |
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97 virtual TInt FetchImage( const TDesC& aUri, RFs& aSession, RFile& aFileHandle ) = 0; |
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98 |
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99 /** |
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100 * This method is called to retrieve the file handle of an svg font file. |
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101 * This file must be SVG 1.1 .svg file. When the engine comes acrossed |
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102 * a font-family name that it doesnt know it will request "fontfamilyname".svg |
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103 * file through this method. The client can either provide the svg file |
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104 * or the engine will default to system text. |
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105 * |
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106 * The usage of this method is exactly the same as the FetchImage method above |
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107 * |
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108 * @since 1.0 |
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109 * @param : aUri -- the relative path of an image file. |
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110 * @param : aSession -- File session used by client to open file. |
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111 * @param : aFileHandle -- File handle used by client to open file. |
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112 * @return : KErrNone if Open command successful, otherwise error-code |
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113 * from Open command. The SVG engine will proceed loading the file |
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114 * only if the return value is KErrNone. |
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115 */ |
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116 virtual TInt FetchFont( const TDesC& aUri, RFs& aSession, RFile& aFileHandle ) = 0; |
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117 |
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118 /** |
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119 * This Method updates the presentation status |
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120 * @since 1.0 |
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121 * @param : TInt32& aNoOfAnimation |
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122 * @return : |
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123 */ |
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124 virtual void UpdatePresentation(const TInt32& aNoOfAnimation)=0; |
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125 |
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126 |
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127 }; |
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128 |
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129 #endif /*__INC_MSvgRequestObserver__*/ |