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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 // |
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15 |
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16 const TUint32 KRBMask = 0x00ff00ff; |
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17 const TUint32 KAGMask = 0xff00ff00; |
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18 const TUint32 KGMask = 0x0000ff00; |
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19 |
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20 const TUint16 NormalisationTable[256] = { |
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21 0,65280,32640,21760,16320,13056,10880,9326,8160,7254,6528, |
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22 5935,5440,5022,4663,4352,4080,3840,3627,3436,3264, |
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23 3109,2968,2839,2720,2612,2511,2418,2332,2252,2176, |
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24 2106,2040,1979,1920,1866,1814,1765,1718,1674,1632, |
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25 1593,1555,1519,1484,1451,1420,1389,1360,1333,1306, |
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26 1280,1256,1232,1209,1187,1166,1146,1126,1107,1088, |
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27 1071,1053,1037,1020,1005,990,975,960,947,933, |
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28 920,907,895,883,871,859,848,837,827,816, |
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29 806,797,787,778,768,760,751,742,734,726, |
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30 718,710,702,695,688,680,673,667,660,653, |
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31 647,640,634,628,622,616,611,605,599,594, |
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32 589,583,578,573,568,563,558,554,549,544, |
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33 540,536,531,527,523,519,515,510,507,503, |
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34 499,495,491,488,484,480,477,474,470,467, |
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35 463,460,457,454,451,448,445,442,439,436, |
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36 433,430,427,424,422,419,416,414,411,408, |
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37 406,403,401,399,396,394,391,389,387,384, |
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38 382,380,378,376,374,371,369,367,365,363, |
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39 361,359,357,355,353,351,350,348,346,344, |
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40 342,340,339,337,335,334,332,330,329,327, |
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41 325,324,322,320,319,317,316,314,313,311, |
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42 310,308,307,306,304,303,301,300,299,297, |
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43 296,295,293,292,291,289,288,287,286,284, |
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44 283,282,281,279,278,277,276,275,274,272, |
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45 271,270,269,268,267,266,265,264,263,262, |
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46 261,260,259,258,256, |
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47 }; |
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48 |
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49 //Algoriths for Premultiplied alpha screenmode/pixel format. |
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50 |
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51 /** |
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52 Blend A over B. From Porter & Duff: |
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53 C = CaFa+CbFb, where Ca = aSrcPixel, Cb = aDest_io, Fa = 1, Fb=(1-Alpha(a)) |
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54 C = Ca+Cb(1-Alpha(a)) |
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55 |
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56 @param aDestPixel Destination pixel. |
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57 @param aSrcPixel Source pixel. |
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58 @param aMaskingFactor Alpha channel of aSrcPixel. |
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59 */ |
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60 inline TUint32 PMABlend_noChecks(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMaskingFactor) |
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61 { |
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62 TUint32 src_c = aSrcPixel & KRBMask; |
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63 TUint32 dst_c = aDestPixel & KRBMask; |
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64 const TUint32 mask = 0x0100 - aMaskingFactor; |
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65 dst_c = (src_c + ((mask * dst_c)>>8)) & KRBMask; |
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66 src_c = (aSrcPixel & KAGMask)>>8; |
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67 TUint32 dst_ag = (aDestPixel & KAGMask)>>8; |
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68 dst_c |= ((src_c + ((mask * dst_ag)>>8)) & KRBMask)<<8; |
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69 return dst_c; |
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70 } |
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71 |
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72 inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMask) |
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73 { |
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74 if(aMask) |
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75 { |
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76 if(aMask == 0xff) // opaque, so unchanged |
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77 { |
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78 return aSrcPixel; |
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79 } |
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80 else |
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81 { |
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82 return PMABlend_noChecks(aDestPixel, aSrcPixel, aMask); |
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83 } |
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84 } |
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85 else // completely transparent |
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86 { |
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87 return aDestPixel; |
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88 } |
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89 } |
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90 |
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91 inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel) |
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92 { |
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93 TUint8 mask = (TUint8)(aSrcPixel >> 24); |
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94 return PMAPixelBlend(aDestPixel, aSrcPixel, mask); |
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95 } |
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96 |
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97 inline TUint32 NonPMA2PMAPixel(TUint32 aPixel) |
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98 { |
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99 TUint8 tA = (TUint8)(aPixel >> 24); |
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100 if (tA==0) |
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101 { |
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102 return 0; |
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103 } |
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104 if (tA==0xff) |
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105 { |
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106 return aPixel; |
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107 } |
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108 |
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109 // Use a bias value of 128 rather than 255, but also add 1/256 of the numerator |
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110 // before dividing the sum by 256. |
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111 |
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112 TUint32 tap1=tA+1; |
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113 TUint32 scaledRB = (aPixel & KRBMask) * tap1; |
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114 TUint32 scaledG = (aPixel & KGMask ) * tap1; |
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115 return (aPixel & 0xff000000) | ((scaledRB>>8) & KRBMask) | ((scaledG>>8)& KGMask); |
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116 } |
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117 |
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118 inline TUint32 PMA2NonPMAPixel(TUint32 aPixel) |
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119 { |
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120 TUint8 alpha = (TUint8)(aPixel >> 24); |
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121 if (alpha==0) |
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122 { |
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123 return 0; |
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124 } |
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125 if (alpha==0xff) |
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126 { |
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127 return aPixel; |
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128 } |
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129 TUint16 norm = NormalisationTable[alpha]; |
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130 TUint32 norm_rb = (((aPixel & KRBMask) * norm) >> 8) & KRBMask; |
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131 TUint32 norm_g = (((aPixel & KGMask ) * norm) >> 8) & KGMask; |
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132 return ((aPixel & 0xff000000) | norm_rb | norm_g); |
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133 } |
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134 |