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1 /* |
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2 SDL - Simple DirectMedia Layer |
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3 Copyright (C) 1997-2006 Sam Lantinga |
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4 |
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5 This library is free software; you can redistribute it and/or |
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6 modify it under the terms of the GNU Lesser General Public |
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7 License as published by the Free Software Foundation; either |
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8 version 2.1 of the License, or (at your option) any later version. |
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9 |
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10 This library is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 Lesser General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU Lesser General Public |
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16 License along with this library; if not, write to the Free Software |
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17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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18 |
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19 Sam Lantinga |
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20 slouken@libsdl.org |
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21 */ |
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22 #include "SDL_config.h" |
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23 |
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24 /* |
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25 Code to load and save surfaces in Windows BMP format. |
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26 |
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27 Why support BMP format? Well, it's a native format for Windows, and |
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28 most image processing programs can read and write it. It would be nice |
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29 to be able to have at least one image format that we can natively load |
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30 and save, and since PNG is so complex that it would bloat the library, |
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31 BMP is a good alternative. |
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32 |
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33 This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp. |
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34 */ |
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35 |
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36 #include "SDL_video.h" |
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37 #include "SDL_endian.h" |
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38 |
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39 /* Compression encodings for BMP files */ |
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40 #ifndef BI_RGB |
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41 #define BI_RGB 0 |
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42 #define BI_RLE8 1 |
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43 #define BI_RLE4 2 |
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44 #define BI_BITFIELDS 3 |
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45 #endif |
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46 |
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47 |
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48 SDL_Surface * SDL_LoadBMP_RW (SDL_RWops *src, int freesrc) |
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49 { |
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50 int was_error; |
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51 long fp_offset; |
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52 int bmpPitch; |
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53 int i, pad; |
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54 SDL_Surface *surface; |
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55 Uint32 Rmask; |
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56 Uint32 Gmask; |
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57 Uint32 Bmask; |
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58 SDL_Palette *palette; |
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59 Uint8 *bits; |
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60 int ExpandBMP; |
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61 |
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62 /* The Win32 BMP file header (14 bytes) */ |
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63 char magic[2]; |
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64 Uint32 bfSize; |
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65 Uint16 bfReserved1; |
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66 Uint16 bfReserved2; |
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67 Uint32 bfOffBits; |
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68 |
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69 /* The Win32 BITMAPINFOHEADER struct (40 bytes) */ |
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70 Uint32 biSize; |
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71 Sint32 biWidth; |
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72 Sint32 biHeight; |
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73 Uint16 biPlanes; |
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74 Uint16 biBitCount; |
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75 Uint32 biCompression; |
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76 Uint32 biSizeImage; |
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77 Sint32 biXPelsPerMeter; |
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78 Sint32 biYPelsPerMeter; |
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79 Uint32 biClrUsed; |
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80 Uint32 biClrImportant; |
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81 |
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82 /* Make sure we are passed a valid data source */ |
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83 surface = NULL; |
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84 was_error = 0; |
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85 if ( src == NULL ) { |
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86 was_error = 1; |
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87 goto done; |
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88 } |
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89 |
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90 /* Read in the BMP file header */ |
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91 fp_offset = SDL_RWtell(src); |
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92 SDL_ClearError(); |
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93 if ( SDL_RWread(src, magic, 1, 2) != 2 ) { |
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94 SDL_Error(SDL_EFREAD); |
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95 was_error = 1; |
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96 goto done; |
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97 } |
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98 if ( SDL_strncmp(magic, "BM", 2) != 0 ) { |
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99 SDL_SetError("File is not a Windows BMP file"); |
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100 was_error = 1; |
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101 goto done; |
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102 } |
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103 bfSize = SDL_ReadLE32(src); |
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104 bfReserved1 = SDL_ReadLE16(src); |
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105 bfReserved2 = SDL_ReadLE16(src); |
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106 bfOffBits = SDL_ReadLE32(src); |
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107 |
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108 /* Read the Win32 BITMAPINFOHEADER */ |
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109 biSize = SDL_ReadLE32(src); |
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110 if ( biSize == 12 ) { |
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111 biWidth = (Uint32)SDL_ReadLE16(src); |
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112 biHeight = (Uint32)SDL_ReadLE16(src); |
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113 biPlanes = SDL_ReadLE16(src); |
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114 biBitCount = SDL_ReadLE16(src); |
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115 biCompression = BI_RGB; |
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116 biSizeImage = 0; |
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117 biXPelsPerMeter = 0; |
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118 biYPelsPerMeter = 0; |
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119 biClrUsed = 0; |
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120 biClrImportant = 0; |
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121 } else { |
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122 biWidth = SDL_ReadLE32(src); |
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123 biHeight = SDL_ReadLE32(src); |
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124 biPlanes = SDL_ReadLE16(src); |
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125 biBitCount = SDL_ReadLE16(src); |
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126 biCompression = SDL_ReadLE32(src); |
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127 biSizeImage = SDL_ReadLE32(src); |
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128 biXPelsPerMeter = SDL_ReadLE32(src); |
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129 biYPelsPerMeter = SDL_ReadLE32(src); |
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130 biClrUsed = SDL_ReadLE32(src); |
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131 biClrImportant = SDL_ReadLE32(src); |
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132 } |
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133 |
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134 /* Check for read error */ |
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135 if ( SDL_strcmp(SDL_GetError(), "") != 0 ) { |
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136 was_error = 1; |
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137 goto done; |
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138 } |
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139 |
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140 /* Expand 1 and 4 bit bitmaps to 8 bits per pixel */ |
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141 switch (biBitCount) { |
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142 case 1: |
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143 case 4: |
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144 ExpandBMP = biBitCount; |
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145 biBitCount = 8; |
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146 break; |
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147 default: |
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148 ExpandBMP = 0; |
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149 break; |
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150 } |
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151 |
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152 /* We don't support any BMP compression right now */ |
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153 Rmask = Gmask = Bmask = 0; |
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154 switch (biCompression) { |
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155 case BI_RGB: |
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156 /* If there are no masks, use the defaults */ |
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157 if ( bfOffBits == (14+biSize) ) { |
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158 /* Default values for the BMP format */ |
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159 switch (biBitCount) { |
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160 case 15: |
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161 case 16: |
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162 Rmask = 0x7C00; |
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163 Gmask = 0x03E0; |
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164 Bmask = 0x001F; |
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165 break; |
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166 case 24: |
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167 #if SDL_BYTEORDER == SDL_BIG_ENDIAN |
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168 Rmask = 0x000000FF; |
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169 Gmask = 0x0000FF00; |
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170 Bmask = 0x00FF0000; |
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171 break; |
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172 #endif |
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173 case 32: |
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174 Rmask = 0x00FF0000; |
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175 Gmask = 0x0000FF00; |
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176 Bmask = 0x000000FF; |
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177 break; |
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178 default: |
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179 break; |
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180 } |
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181 break; |
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182 } |
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183 /* Fall through -- read the RGB masks */ |
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184 |
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185 case BI_BITFIELDS: |
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186 switch (biBitCount) { |
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187 case 15: |
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188 case 16: |
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189 case 32: |
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190 Rmask = SDL_ReadLE32(src); |
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191 Gmask = SDL_ReadLE32(src); |
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192 Bmask = SDL_ReadLE32(src); |
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193 break; |
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194 default: |
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195 break; |
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196 } |
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197 break; |
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198 default: |
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199 SDL_SetError("Compressed BMP files not supported"); |
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200 was_error = 1; |
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201 goto done; |
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202 } |
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203 |
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204 /* Create a compatible surface, note that the colors are RGB ordered */ |
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205 surface = SDL_CreateRGBSurface(SDL_SWSURFACE, |
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206 biWidth, biHeight, biBitCount, Rmask, Gmask, Bmask, 0); |
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207 if ( surface == NULL ) { |
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208 was_error = 1; |
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209 goto done; |
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210 } |
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211 |
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212 /* Load the palette, if any */ |
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213 palette = (surface->format)->palette; |
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214 if ( palette ) { |
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215 if ( biClrUsed == 0 ) { |
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216 biClrUsed = 1 << biBitCount; |
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217 } |
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218 if ( biSize == 12 ) { |
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219 for ( i = 0; i < (int)biClrUsed; ++i ) { |
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220 SDL_RWread(src, &palette->colors[i].b, 1, 1); |
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221 SDL_RWread(src, &palette->colors[i].g, 1, 1); |
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222 SDL_RWread(src, &palette->colors[i].r, 1, 1); |
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223 palette->colors[i].unused = 0; |
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224 } |
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225 } else { |
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226 for ( i = 0; i < (int)biClrUsed; ++i ) { |
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227 SDL_RWread(src, &palette->colors[i].b, 1, 1); |
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228 SDL_RWread(src, &palette->colors[i].g, 1, 1); |
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229 SDL_RWread(src, &palette->colors[i].r, 1, 1); |
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230 SDL_RWread(src, &palette->colors[i].unused, 1, 1); |
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231 } |
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232 } |
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233 palette->ncolors = biClrUsed; |
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234 } |
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235 |
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236 /* Read the surface pixels. Note that the bmp image is upside down */ |
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237 if ( SDL_RWseek(src, fp_offset+bfOffBits, RW_SEEK_SET) < 0 ) { |
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238 SDL_Error(SDL_EFSEEK); |
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239 was_error = 1; |
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240 goto done; |
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241 } |
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242 bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch); |
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243 switch (ExpandBMP) { |
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244 case 1: |
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245 bmpPitch = (biWidth + 7) >> 3; |
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246 pad = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0); |
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247 break; |
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248 case 4: |
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249 bmpPitch = (biWidth + 1) >> 1; |
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250 pad = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0); |
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251 break; |
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252 default: |
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253 pad = ((surface->pitch%4) ? |
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254 (4-(surface->pitch%4)) : 0); |
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255 break; |
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256 } |
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257 while ( bits > (Uint8 *)surface->pixels ) { |
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258 bits -= surface->pitch; |
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259 switch (ExpandBMP) { |
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260 case 1: |
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261 case 4: { |
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262 Uint8 pixel = 0; |
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263 int shift = (8-ExpandBMP); |
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264 for ( i=0; i<surface->w; ++i ) { |
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265 if ( i%(8/ExpandBMP) == 0 ) { |
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266 if ( !SDL_RWread(src, &pixel, 1, 1) ) { |
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267 SDL_SetError( |
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268 "Error reading from BMP"); |
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269 was_error = 1; |
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270 goto done; |
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271 } |
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272 } |
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273 *(bits+i) = (pixel>>shift); |
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274 pixel <<= ExpandBMP; |
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275 } } |
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276 break; |
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277 |
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278 default: |
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279 if ( SDL_RWread(src, bits, 1, surface->pitch) |
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280 != surface->pitch ) { |
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281 SDL_Error(SDL_EFREAD); |
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282 was_error = 1; |
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283 goto done; |
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284 } |
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285 #if SDL_BYTEORDER == SDL_BIG_ENDIAN |
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286 /* Byte-swap the pixels if needed. Note that the 24bpp |
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287 case has already been taken care of above. */ |
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288 switch(biBitCount) { |
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289 case 15: |
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290 case 16: { |
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291 Uint16 *pix = (Uint16 *)bits; |
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292 for(i = 0; i < surface->w; i++) |
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293 pix[i] = SDL_Swap16(pix[i]); |
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294 break; |
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295 } |
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296 |
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297 case 32: { |
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298 Uint32 *pix = (Uint32 *)bits; |
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299 for(i = 0; i < surface->w; i++) |
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300 pix[i] = SDL_Swap32(pix[i]); |
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301 break; |
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302 } |
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303 } |
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304 #endif |
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305 break; |
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306 } |
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307 /* Skip padding bytes, ugh */ |
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308 if ( pad ) { |
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309 Uint8 padbyte; |
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310 for ( i=0; i<pad; ++i ) { |
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311 SDL_RWread(src, &padbyte, 1, 1); |
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312 } |
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313 } |
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314 } |
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315 done: |
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316 if ( was_error ) { |
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317 if ( src ) { |
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318 SDL_RWseek(src, fp_offset, RW_SEEK_SET); |
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319 } |
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320 if ( surface ) { |
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321 SDL_FreeSurface(surface); |
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322 } |
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323 surface = NULL; |
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324 } |
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325 if ( freesrc && src ) { |
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326 SDL_RWclose(src); |
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327 } |
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328 return(surface); |
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329 } |
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330 |
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331 int SDL_SaveBMP_RW (SDL_Surface *saveme, SDL_RWops *dst, int freedst) |
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332 { |
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333 long fp_offset; |
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334 int i, pad; |
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335 SDL_Surface *surface; |
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336 Uint8 *bits; |
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337 |
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338 /* The Win32 BMP file header (14 bytes) */ |
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339 char magic[2] = { 'B', 'M' }; |
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340 Uint32 bfSize; |
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341 Uint16 bfReserved1; |
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342 Uint16 bfReserved2; |
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343 Uint32 bfOffBits; |
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344 |
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345 /* The Win32 BITMAPINFOHEADER struct (40 bytes) */ |
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346 Uint32 biSize; |
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347 Sint32 biWidth; |
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348 Sint32 biHeight; |
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349 Uint16 biPlanes; |
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350 Uint16 biBitCount; |
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351 Uint32 biCompression; |
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352 Uint32 biSizeImage; |
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353 Sint32 biXPelsPerMeter; |
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354 Sint32 biYPelsPerMeter; |
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355 Uint32 biClrUsed; |
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356 Uint32 biClrImportant; |
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357 |
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358 /* Make sure we have somewhere to save */ |
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359 surface = NULL; |
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360 if ( dst ) { |
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361 if ( saveme->format->palette ) { |
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362 if ( saveme->format->BitsPerPixel == 8 ) { |
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363 surface = saveme; |
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364 } else { |
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365 SDL_SetError("%d bpp BMP files not supported", |
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366 saveme->format->BitsPerPixel); |
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367 } |
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368 } |
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369 else if ( (saveme->format->BitsPerPixel == 24) && |
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370 #if SDL_BYTEORDER == SDL_LIL_ENDIAN |
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371 (saveme->format->Rmask == 0x00FF0000) && |
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372 (saveme->format->Gmask == 0x0000FF00) && |
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373 (saveme->format->Bmask == 0x000000FF) |
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374 #else |
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375 (saveme->format->Rmask == 0x000000FF) && |
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376 (saveme->format->Gmask == 0x0000FF00) && |
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377 (saveme->format->Bmask == 0x00FF0000) |
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378 #endif |
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379 ) { |
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380 surface = saveme; |
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381 } else { |
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382 SDL_Rect bounds; |
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383 |
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384 /* Convert to 24 bits per pixel */ |
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385 surface = SDL_CreateRGBSurface(SDL_SWSURFACE, |
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386 saveme->w, saveme->h, 24, |
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387 #if SDL_BYTEORDER == SDL_LIL_ENDIAN |
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388 0x00FF0000, 0x0000FF00, 0x000000FF, |
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389 #else |
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390 0x000000FF, 0x0000FF00, 0x00FF0000, |
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391 #endif |
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392 0); |
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393 if ( surface != NULL ) { |
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394 bounds.x = 0; |
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395 bounds.y = 0; |
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396 bounds.w = saveme->w; |
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397 bounds.h = saveme->h; |
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398 if ( SDL_LowerBlit(saveme, &bounds, surface, |
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399 &bounds) < 0 ) { |
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400 SDL_FreeSurface(surface); |
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401 SDL_SetError( |
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402 "Couldn't convert image to 24 bpp"); |
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403 surface = NULL; |
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404 } |
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405 } |
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406 } |
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407 } |
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408 |
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409 if ( surface && (SDL_LockSurface(surface) == 0) ) { |
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410 const int bw = surface->w*surface->format->BytesPerPixel; |
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411 |
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412 /* Set the BMP file header values */ |
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413 bfSize = 0; /* We'll write this when we're done */ |
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414 bfReserved1 = 0; |
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415 bfReserved2 = 0; |
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416 bfOffBits = 0; /* We'll write this when we're done */ |
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417 |
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418 /* Write the BMP file header values */ |
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419 fp_offset = SDL_RWtell(dst); |
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420 SDL_ClearError(); |
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421 SDL_RWwrite(dst, magic, 2, 1); |
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422 SDL_WriteLE32(dst, bfSize); |
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423 SDL_WriteLE16(dst, bfReserved1); |
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424 SDL_WriteLE16(dst, bfReserved2); |
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425 SDL_WriteLE32(dst, bfOffBits); |
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426 |
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427 /* Set the BMP info values */ |
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428 biSize = 40; |
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429 biWidth = surface->w; |
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430 biHeight = surface->h; |
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431 biPlanes = 1; |
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432 biBitCount = surface->format->BitsPerPixel; |
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433 biCompression = BI_RGB; |
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434 biSizeImage = surface->h*surface->pitch; |
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435 biXPelsPerMeter = 0; |
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436 biYPelsPerMeter = 0; |
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437 if ( surface->format->palette ) { |
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438 biClrUsed = surface->format->palette->ncolors; |
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439 } else { |
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440 biClrUsed = 0; |
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441 } |
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442 biClrImportant = 0; |
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443 |
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444 /* Write the BMP info values */ |
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445 SDL_WriteLE32(dst, biSize); |
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446 SDL_WriteLE32(dst, biWidth); |
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447 SDL_WriteLE32(dst, biHeight); |
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448 SDL_WriteLE16(dst, biPlanes); |
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449 SDL_WriteLE16(dst, biBitCount); |
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450 SDL_WriteLE32(dst, biCompression); |
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451 SDL_WriteLE32(dst, biSizeImage); |
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452 SDL_WriteLE32(dst, biXPelsPerMeter); |
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453 SDL_WriteLE32(dst, biYPelsPerMeter); |
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454 SDL_WriteLE32(dst, biClrUsed); |
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455 SDL_WriteLE32(dst, biClrImportant); |
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456 |
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457 /* Write the palette (in BGR color order) */ |
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458 if ( surface->format->palette ) { |
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459 SDL_Color *colors; |
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460 int ncolors; |
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461 |
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462 colors = surface->format->palette->colors; |
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463 ncolors = surface->format->palette->ncolors; |
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464 for ( i=0; i<ncolors; ++i ) { |
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465 SDL_RWwrite(dst, &colors[i].b, 1, 1); |
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466 SDL_RWwrite(dst, &colors[i].g, 1, 1); |
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467 SDL_RWwrite(dst, &colors[i].r, 1, 1); |
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468 SDL_RWwrite(dst, &colors[i].unused, 1, 1); |
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469 } |
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470 } |
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471 |
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472 /* Write the bitmap offset */ |
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473 bfOffBits = SDL_RWtell(dst)-fp_offset; |
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474 if ( SDL_RWseek(dst, fp_offset+10, RW_SEEK_SET) < 0 ) { |
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475 SDL_Error(SDL_EFSEEK); |
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476 } |
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477 SDL_WriteLE32(dst, bfOffBits); |
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478 if ( SDL_RWseek(dst, fp_offset+bfOffBits, RW_SEEK_SET) < 0 ) { |
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479 SDL_Error(SDL_EFSEEK); |
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480 } |
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481 |
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482 /* Write the bitmap image upside down */ |
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483 bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch); |
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484 pad = ((bw%4) ? (4-(bw%4)) : 0); |
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485 while ( bits > (Uint8 *)surface->pixels ) { |
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486 bits -= surface->pitch; |
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487 if ( SDL_RWwrite(dst, bits, 1, bw) != bw) { |
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488 SDL_Error(SDL_EFWRITE); |
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489 break; |
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490 } |
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491 if ( pad ) { |
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492 const Uint8 padbyte = 0; |
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493 for ( i=0; i<pad; ++i ) { |
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494 SDL_RWwrite(dst, &padbyte, 1, 1); |
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495 } |
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496 } |
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497 } |
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498 |
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499 /* Write the BMP file size */ |
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500 bfSize = SDL_RWtell(dst)-fp_offset; |
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501 if ( SDL_RWseek(dst, fp_offset+2, RW_SEEK_SET) < 0 ) { |
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502 SDL_Error(SDL_EFSEEK); |
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503 } |
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504 SDL_WriteLE32(dst, bfSize); |
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505 if ( SDL_RWseek(dst, fp_offset+bfSize, RW_SEEK_SET) < 0 ) { |
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506 SDL_Error(SDL_EFSEEK); |
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507 } |
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508 |
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509 /* Close it up.. */ |
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510 SDL_UnlockSurface(surface); |
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511 if ( surface != saveme ) { |
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512 SDL_FreeSurface(surface); |
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513 } |
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514 } |
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515 |
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516 if ( freedst && dst ) { |
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517 SDL_RWclose(dst); |
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518 } |
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519 return((SDL_strcmp(SDL_GetError(), "") == 0) ? 0 : -1); |
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520 } |