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1 // Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // FONT related functions and the font cache |
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15 // |
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16 // |
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17 |
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18 #include "wsfont.h" |
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19 |
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20 CWsFontCache * CWsFontCache::iSelf = NULL; |
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21 TDblQue<CWsFbsFont> * CWsFontCache::iList = NULL; |
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22 |
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23 CWsFontCache::CWsFontCache() |
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24 { |
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25 } |
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26 |
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27 CWsFontCache::~CWsFontCache() |
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28 { |
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29 } |
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30 |
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31 void CWsFontCache::CreateInstanceL() |
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32 { |
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33 // The list MUST exist before creation of the cache since the cache |
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34 // contains an array of fonts. When the array is created the fonts add themselves |
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35 // to the list. |
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36 // The list is ordered from newest to oldest font used. |
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37 iList = new (ELeave) TDblQue<CWsFbsFont>(_FOFF(CWsFbsFont,iLink)); |
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38 CleanupStack::PushL(iList); |
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39 iSelf = new (ELeave) CWsFontCache; |
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40 CleanupStack::Pop(iList); |
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41 } |
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42 |
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43 void CWsFontCache::DestroyInstance() |
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44 { |
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45 // The cache has to be destroyed first since the fonts are |
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46 // destroyed when the cache's array if destroyed. The fonts |
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47 // remove themselves from the list |
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48 delete iSelf; |
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49 iSelf = NULL; |
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50 delete iList; |
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51 iList = NULL; |
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52 |
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53 } |
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54 |
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55 void CWsFontCache::ReleaseFont(CWsFbsFont *&aFont) |
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56 { |
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57 if (aFont) |
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58 { |
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59 WS_ASSERT_DEBUG(aFont->iCount>0, EWsPanicFontCacheCount); |
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60 // decrease usage count |
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61 aFont->iCount--; |
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62 // when the font reaches zero then the font entry can be reused later |
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63 aFont = NULL; |
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64 } |
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65 } |
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66 |
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67 TBool CWsFontCache::UseFont(CWsFbsFont *&aFont, TInt aHandle) |
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68 { |
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69 ReleaseFont(aFont); |
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70 CWsFbsFont *font = NULL; |
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71 |
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72 // The list is ordered from newest to oldest font used. |
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73 TDblQueIter<CWsFbsFont> iter(*iList); |
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74 |
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75 |
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76 // Search for the font from newest to oldest font |
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77 while ((font = iter++) != NULL) |
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78 { |
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79 // if the font handle already exists use existing font |
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80 if (font->Handle() == aHandle) |
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81 { |
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82 break; |
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83 } |
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84 } |
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85 |
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86 // Font not found in cache so find an unused entry |
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87 if (!font) |
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88 { |
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89 // Starting search from oldest to newest font unsed |
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90 iter.SetToLast(); |
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91 while((font = iter--) != NULL) |
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92 { |
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93 // if you find an unused font then use that font entry |
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94 if (font->iCount == 0) |
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95 { |
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96 break; |
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97 } |
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98 } |
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99 // if an unused font is not found then all fonts are being used and |
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100 // the font can not be created |
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101 if (!font) |
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102 { |
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103 return(ETrue); // No room in cache |
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104 } |
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105 // release and reuse the font entry to create a new font |
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106 font->Reset(); |
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107 if (font->Duplicate(aHandle) != KErrNone) |
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108 { |
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109 return(EFalse); // Bad handle, (indicated by aFont=NULL) |
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110 } |
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111 } |
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112 // put font at the font of the list as the font is the newest font |
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113 font->iLink.Deque(); |
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114 iList->AddFirst(*font); |
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115 // increase usage count |
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116 font->iCount++; |
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117 aFont = font; |
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118 return(EFalse); |
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119 } |
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120 |
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121 TDblQue<CWsFbsFont>& CWsFontCache::List() |
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122 { |
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123 return *Instance()->iList; |
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124 } |
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125 |
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126 CWsFbsFont::CWsFbsFont() |
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127 { |
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128 // add itself to the font cache |
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129 CWsFontCache::List().AddLast(*this); |
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130 } |
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131 |
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132 CWsFbsFont::~CWsFbsFont() |
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133 { |
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134 // remove itself from the font cache |
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135 iLink.Deque(); |
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136 WS_ASSERT_DEBUG(iCount==0, EWsPanicFontCacheCount); |
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137 } |