1 | /* |
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2 | * ---------------------------------------------------------------------- |
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3 | * RpSqueezer - image distortion for "cover flow" effect. |
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4 | * |
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5 | * Modifies a Tk image to squeeze one side or the other and perhaps |
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6 | * foreshorten the image. |
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7 | * |
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8 | * squeezer ?options...? <original> <newImage> |
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9 | * -side left|right << which side to squeeze |
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10 | * -amount <fraction> << squeeze down to this size (0-1) |
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11 | * -shorten <fraction> << squeeze horizontally to this size (0-1) |
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12 | * -shadow <fraction> << apply shadow horizontally (strength 0-1) |
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13 | * |
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14 | * ====================================================================== |
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15 | * AUTHOR: Michael McLennan, Purdue University |
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16 | * Copyright (c) 2004-2012 HUBzero Foundation, LLC |
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17 | * |
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18 | * See the file "license.terms" for information on usage and |
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19 | * redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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20 | * ====================================================================== |
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21 | */ |
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22 | #include <string.h> |
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23 | #include <math.h> |
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24 | #include "tk.h" |
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25 | |
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26 | /* |
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27 | * Forward declarations. |
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28 | */ |
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29 | static int RpSqueezerCmd _ANSI_ARGS_((ClientData clientData, |
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30 | Tcl_Interp *interp, int argc, CONST char **argv)); |
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31 | |
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32 | /* |
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33 | * ------------------------------------------------------------------------ |
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34 | * RpSqueezer_Init -- |
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35 | * |
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36 | * Installs the "squeezer" command in a Tcl interpreter. |
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37 | * |
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38 | * Returns TCL_OK if successful, or TCL_ERROR (along with an error |
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39 | * message in the interp) if anything goes wrong. |
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40 | * ------------------------------------------------------------------------ |
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41 | */ |
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42 | int |
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43 | RpSqueezer_Init(interp) |
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44 | Tcl_Interp *interp; /* interpreter being initialized */ |
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45 | { |
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46 | /* install the widget command */ |
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47 | Tcl_CreateCommand(interp, "squeezer", RpSqueezerCmd, |
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48 | NULL, NULL); |
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49 | |
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50 | return TCL_OK; |
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51 | } |
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52 | |
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53 | /* |
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54 | * ---------------------------------------------------------------------- |
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55 | * RpSqueezerCmd() |
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56 | * |
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57 | * Called to handle the "squeezer" command. Returns TCL_OK on success |
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58 | * and TCL_ERROR otherwise. |
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59 | * ---------------------------------------------------------------------- |
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60 | */ |
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61 | static int |
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62 | RpSqueezerCmd(clientData, interp, argc, argv) |
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63 | ClientData clientData; /* not used */ |
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64 | Tcl_Interp *interp; /* current interpreter */ |
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65 | int argc; /* number of command arguments */ |
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66 | CONST char **argv; /* command argument strings */ |
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67 | { |
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68 | int sideRight = 1; |
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69 | double amount = 0.8; |
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70 | double shorten = 0.7; |
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71 | double shadow = 0.0; |
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72 | |
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73 | int i, j, j0, j1, p, srcw, srch, destw, desth, nbytes; |
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74 | int srci, srcj, rval, gval, bval, aval; |
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75 | double shfac; |
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76 | Tk_PhotoHandle srcPhoto, destPhoto; |
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77 | Tk_PhotoImageBlock srcBlock, destBlock; |
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78 | unsigned char* pixelPtr; |
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79 | |
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80 | /* parse command line options */ |
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81 | i = 1; |
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82 | while (i < argc) { |
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83 | if (*argv[i] != '-') { |
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84 | break; |
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85 | } |
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86 | if (i+1 >= argc) { |
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87 | Tcl_AppendResult(interp, "missing value for option \"", |
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88 | argv[i], "\"", (char*)NULL); |
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89 | return TCL_ERROR; |
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90 | } |
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91 | |
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92 | if (strcmp(argv[i],"-side") == 0) { |
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93 | if (strcmp(argv[i+1],"left") == 0) { |
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94 | sideRight = 0; |
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95 | } else if (strcmp(argv[i+1],"right") == 0) { |
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96 | sideRight = 1; |
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97 | } else { |
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98 | Tcl_AppendResult(interp, "bad value \"", |
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99 | argv[i+1], "\": should be left or right", (char*)NULL); |
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100 | return TCL_ERROR; |
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101 | } |
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102 | } |
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103 | else if (strcmp(argv[i],"-amount") == 0) { |
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104 | if (Tcl_GetDouble(interp, argv[i+1], &amount) != TCL_OK) { |
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105 | return TCL_ERROR; |
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106 | } |
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107 | } |
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108 | else if (strcmp(argv[i],"-shorten") == 0) { |
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109 | if (Tcl_GetDouble(interp, argv[i+1], &shorten) != TCL_OK) { |
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110 | return TCL_ERROR; |
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111 | } |
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112 | } |
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113 | else if (strcmp(argv[i],"-shadow") == 0) { |
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114 | if (Tcl_GetDouble(interp, argv[i+1], &shadow) != TCL_OK) { |
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115 | return TCL_ERROR; |
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116 | } |
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117 | } |
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118 | else { |
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119 | Tcl_AppendResult(interp, "bad option \"", argv[i], |
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120 | "\": should be -side, -amount, -shorten, -shadow", |
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121 | (char*)NULL); |
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122 | return TCL_ERROR; |
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123 | } |
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124 | |
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125 | i += 2; |
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126 | } |
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127 | |
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128 | if (i+2 != argc) { |
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129 | Tcl_AppendResult(interp, "wrong # args: should be \"", |
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130 | argv[0], " ?options? origImg newImg\"", (char*)NULL); |
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131 | return TCL_ERROR; |
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132 | } |
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133 | |
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134 | /* get the last two args... source and destination images */ |
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135 | srcPhoto = Tk_FindPhoto(interp, argv[i]); |
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136 | if (srcPhoto == NULL) { |
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137 | Tcl_AppendResult(interp, "image \"", argv[i], "doesn't exist", |
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138 | " or isn't a photo image", (char*)NULL); |
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139 | return TCL_ERROR; |
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140 | } |
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141 | |
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142 | destPhoto = Tk_FindPhoto(interp, argv[i+1]); |
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143 | if (destPhoto == NULL) { |
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144 | Tcl_AppendResult(interp, "image \"", argv[i+1], "doesn't exist", |
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145 | " or isn't a photo image", (char*)NULL); |
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146 | return TCL_ERROR; |
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147 | } |
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148 | |
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149 | /* |
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150 | * Update the destination image to the proper size. |
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151 | */ |
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152 | Tk_PhotoGetSize(srcPhoto, &srcw, &srch); |
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153 | destw = round(srcw * shorten); |
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154 | |
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155 | /* |
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156 | * Scan through each column along the width. Compute the height |
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157 | * of the shortened column and then compute the pixels along the |
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158 | * height. |
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159 | */ |
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160 | Tk_PhotoGetImage(srcPhoto, &srcBlock); |
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161 | |
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162 | destBlock.width = destw; |
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163 | destBlock.height = srch; |
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164 | destBlock.pixelSize = 4; |
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165 | destBlock.offset[0] = 0; |
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166 | destBlock.offset[1] = 1; |
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167 | destBlock.offset[2] = 2; |
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168 | destBlock.offset[3] = 3; |
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169 | destBlock.pitch = destBlock.pixelSize * destw; |
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170 | nbytes = destBlock.pitch * srch; |
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171 | destBlock.pixelPtr = (unsigned char*)ckalloc((unsigned)nbytes); |
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172 | memset(destBlock.pixelPtr, 0, (size_t)nbytes); |
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173 | |
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174 | for (p=0; p < destw; p++) { |
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175 | i = (sideRight) ? p : destw-p-1; |
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176 | desth = round(srch - srch*(1.0-amount)*p/(double)destw); |
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177 | j0 = (srch-desth)/2; |
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178 | j1 = j0 + desth; |
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179 | |
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180 | /* strength of shadow */ |
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181 | shfac = 1.0 - shadow * p/(double)destw; |
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182 | |
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183 | for (j=j0; j < j1; j++) { |
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184 | srci = srcw * i/(double)destw; |
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185 | srcj = srch * (j-j0)/(double)desth; |
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186 | pixelPtr = srcBlock.pixelPtr + srcj*srcBlock.pitch |
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187 | + srci*srcBlock.pixelSize; |
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188 | rval = *(pixelPtr+srcBlock.offset[0]); |
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189 | gval = *(pixelPtr+srcBlock.offset[1]); |
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190 | bval = *(pixelPtr+srcBlock.offset[2]); |
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191 | aval = *(pixelPtr+srcBlock.offset[3]); |
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192 | |
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193 | pixelPtr = destBlock.pixelPtr + j*destBlock.pitch |
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194 | + i*destBlock.pixelSize; |
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195 | *(pixelPtr+0) = round(rval*shfac); |
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196 | *(pixelPtr+1) = round(gval*shfac); |
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197 | *(pixelPtr+2) = round(bval*shfac); |
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198 | *(pixelPtr+3) = aval; |
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199 | } |
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200 | } |
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201 | Tk_PhotoSetSize(destPhoto, destw, srch); |
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202 | Tk_PhotoPutBlock(destPhoto, &destBlock, 0, 0, |
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203 | destBlock.width, destBlock.height, TK_PHOTO_COMPOSITE_SET); |
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204 | |
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205 | ckfree((char*)destBlock.pixelPtr); |
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206 | return TCL_OK; |
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207 | } |
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