1 blendingalgorithms.inl |
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 the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.symbianfoundation.org/legal/licencesv10.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 //Algoriths for Premultiplied alpha screenmode/pixel format. |
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21 |
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22 inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMask) |
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23 { |
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24 if(aMask) |
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25 { |
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26 if(aMask == 0xff) // opaque, so unchanged |
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27 { |
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28 return aSrcPixel; |
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29 } |
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30 else |
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31 { |
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32 return PMABlend_noChecks(aDestPixel, aSrcPixel, aMask); |
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33 } |
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34 } |
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35 else // completely transparent |
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36 { |
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37 return aDestPixel; |
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38 } |
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39 } |
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40 |
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41 inline TUint32 PMAPixelBlend(TUint32 aDestPixel, TUint32 aSrcPixel) |
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42 { |
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43 TUint8 mask = (TUint8)(aSrcPixel >> 24); |
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44 return PMAPixelBlend(aDestPixel, aSrcPixel, mask); |
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45 } |
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46 |
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47 inline TUint32 PMABlend_noChecks(TUint32 aDestPixel, TUint32 aSrcPixel, TUint8 aMaskingFactor) |
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48 { |
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49 TUint32 src_c = aSrcPixel & KRBMask; |
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50 TUint32 dst_c = aDestPixel & KRBMask; |
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51 const TUint32 mask = 0x0100 - aMaskingFactor; |
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52 dst_c = (src_c + ((mask * dst_c)>>8)) & KRBMask; |
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53 src_c = (aSrcPixel & KAGMask)>>8; |
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54 TUint32 dst_ag = (aDestPixel & KAGMask)>>8; |
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55 dst_c |= ((src_c + ((mask * dst_ag)>>8)) & KRBMask)<<8; |
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56 return dst_c; |
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57 } |
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58 |
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59 inline void PMABlend_noChecksInplace(TUint32& aDest_io, TUint32& aSrcPixel,TUint8& aMaskingFactor) |
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60 { |
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61 TUint32 src_c = aSrcPixel & KRBMask; |
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62 TUint32 dst_ag = (aDest_io & KAGMask) >> 8; |
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63 aDest_io = aDest_io & KRBMask; |
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64 const TUint32 mask = 0x0100 - aMaskingFactor; |
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65 aDest_io = (src_c + ((mask * aDest_io) >> 8)) & KRBMask; |
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66 src_c = (aSrcPixel & KAGMask) >> 8; |
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67 aDest_io |= ((src_c + ((mask * dst_ag) >> 8)) & KRBMask)<<8; |
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68 } |
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69 |
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70 inline void PMAInplaceBlend(TUint32& aDest_io, TUint32& aSrc_in) |
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71 { |
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72 TUint8 mask = (TUint8)(aSrc_in >> 24); |
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73 if(mask) |
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74 { |
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75 if(mask == 0xff) // opaque, so dst = src. |
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76 { |
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77 aDest_io = aSrc_in; |
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78 } |
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79 else |
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80 { |
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81 PMABlend_noChecksInplace(aDest_io, aSrc_in, mask); |
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82 } |
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83 } |
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84 //else src completely transparent, so dst unchanged. |
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85 } |
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86 |
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87 inline TUint32 NonPMA2PMAPixel(TUint32 aPixel) |
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88 { |
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89 TUint8 tA = (TUint8)(aPixel >> 24); |
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90 if (tA==0) |
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91 { |
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92 return 0; |
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93 } |
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94 if (tA==0xff) |
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95 { |
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96 return aPixel; |
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97 } |
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98 |
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99 // Use a bias value of 128 rather than 255, but also add 1/256 of the numerator |
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100 // before dividing the sum by 256. |
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101 |
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102 TUint32 tap1=tA+1; |
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103 TUint32 scaledRB = (aPixel & KRBMask) * tap1; |
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104 TUint32 scaledG = (aPixel & KGMask ) * tap1; |
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105 return (aPixel & 0xff000000) | ((scaledRB>>8) & KRBMask) | ((scaledG>>8)& KGMask); |
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106 } |
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107 |
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108 inline TUint32 PMA2NonPMAPixel(TUint32 aPixel, const TUint16* aNormTable) |
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109 { |
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110 TUint8 alpha = (TUint8)(aPixel >> 24); |
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111 if (alpha==0) |
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112 { |
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113 return 0; |
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114 } |
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115 if (alpha==0xff) |
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116 { |
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117 return aPixel; |
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118 } |
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119 TUint16 norm = aNormTable[alpha]; |
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120 TUint32 norm_rb = (((aPixel & KRBMask) * norm) >> 8) & KRBMask; |
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121 TUint32 norm_g = (((aPixel & KGMask ) * norm) >> 8) & KGMask; |
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122 return ((aPixel & 0xff000000) | norm_rb | norm_g); |
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123 } |
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124 |
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125 inline void Convert2PMA(TUint32& aInOutValue) |
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126 { |
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127 aInOutValue = NonPMA2PMAPixel(aInOutValue); |
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128 } |
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129 |
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130 inline void Convert2NonPMA(TUint32& aInOutValue, const TUint16* aNormTable) |
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131 { |
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132 aInOutValue = PMA2NonPMAPixel(aInOutValue, aNormTable); |
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133 } |