1 /* 2 * Copyright 2006 The Android Open Source Project 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #include "SkColorPriv.h" 9 #include "SkImageDecoder.h" 10 #include "SkStream.h" 11 #include "SkStreamHelpers.h" 12 #include "SkTypes.h" 13 14 class SkICOImageDecoder : public SkImageDecoder { 15 public: 16 SkICOImageDecoder(); 17 18 virtual Format getFormat() const SK_OVERRIDE { 19 return kICO_Format; 20 } 21 22 protected: 23 virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE; 24 25 private: 26 typedef SkImageDecoder INHERITED; 27 }; 28 29 ///////////////////////////////////////////////////////////////////////////////////////// 30 31 //read bytes starting from the begin-th index in the buffer 32 //read in Intel order, and return an integer 33 34 #define readByte(buffer,begin) buffer[begin] 35 #define read2Bytes(buffer,begin) buffer[begin]+(buffer[begin+1]<<8) 36 #define read4Bytes(buffer,begin) buffer[begin]+(buffer[begin+1]<<8)+(buffer[begin+2]<<16)+(buffer[begin+3]<<24) 37 38 ///////////////////////////////////////////////////////////////////////////////////////// 39 40 SkICOImageDecoder::SkICOImageDecoder() 41 { 42 } 43 44 //helpers - my function pointer will call one of these, depending on the bitCount, each time through the inner loop 45 static void editPixelBit1(const int pixelNo, const unsigned char* buf, 46 const int xorOffset, int& x, int y, const int w, 47 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors); 48 static void editPixelBit4(const int pixelNo, const unsigned char* buf, 49 const int xorOffset, int& x, int y, const int w, 50 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors); 51 static void editPixelBit8(const int pixelNo, const unsigned char* buf, 52 const int xorOffset, int& x, int y, const int w, 53 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors); 54 static void editPixelBit24(const int pixelNo, const unsigned char* buf, 55 const int xorOffset, int& x, int y, const int w, 56 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors); 57 static void editPixelBit32(const int pixelNo, const unsigned char* buf, 58 const int xorOffset, int& x, int y, const int w, 59 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors); 60 61 62 static int calculateRowBytesFor8888(int w, int bitCount) 63 { 64 // Default rowBytes is w << 2 for kARGB_8888 65 // In the case of a 4 bit image with an odd width, we need to add some 66 // so we can go off the end of the drawn bitmap. 67 // Add 4 to ensure that it is still a multiple of 4. 68 if (4 == bitCount && (w & 0x1)) { 69 return (w + 1) << 2; 70 } 71 // Otherwise return 0, which will allow it to be calculated automatically. 72 return 0; 73 } 74 75 bool SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) 76 { 77 SkAutoMalloc autoMal; 78 const size_t length = CopyStreamToStorage(&autoMal, stream); 79 if (0 == length) { 80 return false; 81 } 82 83 unsigned char* buf = (unsigned char*)autoMal.get(); 84 85 //these should always be the same - should i use for error checking? - what about files that have some 86 //incorrect values, but still decode properly? 87 int reserved = read2Bytes(buf, 0); // 0 88 int type = read2Bytes(buf, 2); // 1 89 if (reserved != 0 || type != 1) 90 return false; 91 int count = read2Bytes(buf, 4); 92 93 //need to at least have enough space to hold the initial table of info 94 if (length < (size_t)(6 + count*16)) 95 return false; 96 97 #ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER 98 int choice; 99 Chooser* chooser = this->getChooser(); 100 //FIXME:if no chooser, consider providing the largest color image 101 //what are the odds that the largest image would be monochrome? 102 if (NULL == chooser) { 103 choice = 0; 104 } else { 105 chooser->begin(count); 106 for (int i = 0; i < count; i++) 107 { 108 //need to find out the config, width, and height from the stream 109 int width = readByte(buf, 6 + i*16); 110 int height = readByte(buf, 7 + i*16); 111 int offset = read4Bytes(buf, 18 + i*16); 112 int bitCount = read2Bytes(buf, offset+14); 113 SkBitmap::Config c; 114 //currently only provide ARGB_8888_, but maybe we want kIndex8_Config for 1 and 4, and possibly 8? 115 //or maybe we'll determine this based on the provided config 116 switch (bitCount) 117 { 118 case 1: 119 case 4: 120 // In reality, at least for the moment, these will be decoded into kARGB_8888 bitmaps. 121 // However, this will be used to distinguish between the lower quality 1bpp and 4 bpp 122 // images and the higher quality images. 123 c = SkBitmap::kIndex8_Config; 124 break; 125 case 8: 126 case 24: 127 case 32: 128 c = SkBitmap::kARGB_8888_Config; 129 break; 130 default: 131 SkDEBUGF(("Image with %ibpp not supported\n", bitCount)); 132 continue; 133 } 134 chooser->inspect(i, c, width, height); 135 } 136 choice = chooser->choose(); 137 } 138 139 //you never know what the chooser is going to supply 140 if (choice >= count || choice < 0) 141 return false; 142 #else 143 const int choice = 0; // TODO: fold this value into the expressions below 144 #endif 145 146 //skip ahead to the correct header 147 //commented out lines are not used, but if i switch to other read method, need to know how many to skip 148 //otherwise, they could be used for error checking 149 int w = readByte(buf, 6 + choice*16); 150 int h = readByte(buf, 7 + choice*16); 151 int colorCount = readByte(buf, 8 + choice*16); 152 //int reservedToo = readByte(buf, 9 + choice*16); //0 153 //int planes = read2Bytes(buf, 10 + choice*16); //1 - but often 0 154 //int fakeBitCount = read2Bytes(buf, 12 + choice*16); //should be real - usually 0 155 int size = read4Bytes(buf, 14 + choice*16); //matters? 156 int offset = read4Bytes(buf, 18 + choice*16); 157 if ((size_t)(offset + size) > length) 158 return false; 159 160 // Check to see if this is a PNG image inside the ICO 161 { 162 SkMemoryStream subStream(buf + offset, size, false); 163 SkAutoTDelete<SkImageDecoder> otherDecoder(SkImageDecoder::Factory(&subStream)); 164 if (otherDecoder.get() != NULL) { 165 // Set fields on the other decoder to be the same as this one. 166 this->copyFieldsToOther(otherDecoder.get()); 167 if(otherDecoder->decode(&subStream, bm, this->getDefaultPref(), mode)) { 168 return true; 169 } 170 } 171 } 172 173 //int infoSize = read4Bytes(buf, offset); //40 174 //int width = read4Bytes(buf, offset+4); //should == w 175 //int height = read4Bytes(buf, offset+8); //should == 2*h 176 //int planesToo = read2Bytes(buf, offset+12); //should == 1 (does it?) 177 int bitCount = read2Bytes(buf, offset+14); 178 179 void (*placePixel)(const int pixelNo, const unsigned char* buf, 180 const int xorOffset, int& x, int y, const int w, 181 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors) = NULL; 182 switch (bitCount) 183 { 184 case 1: 185 placePixel = &editPixelBit1; 186 colorCount = 2; 187 break; 188 case 4: 189 placePixel = &editPixelBit4; 190 colorCount = 16; 191 break; 192 case 8: 193 placePixel = &editPixelBit8; 194 colorCount = 256; 195 break; 196 case 24: 197 placePixel = &editPixelBit24; 198 colorCount = 0; 199 break; 200 case 32: 201 placePixel = &editPixelBit32; 202 colorCount = 0; 203 break; 204 default: 205 SkDEBUGF(("Decoding %ibpp is unimplemented\n", bitCount)); 206 return false; 207 } 208 209 //these should all be zero, but perhaps are not - need to check 210 //int compression = read4Bytes(buf, offset+16); //0 211 //int imageSize = read4Bytes(buf, offset+20); //0 - sometimes has a value 212 //int xPixels = read4Bytes(buf, offset+24); //0 213 //int yPixels = read4Bytes(buf, offset+28); //0 214 //int colorsUsed = read4Bytes(buf, offset+32) //0 - might have an actual value though 215 //int colorsImportant = read4Bytes(buf, offset+36); //0 216 217 int begin = offset + 40; 218 //this array represents the colortable 219 //if i allow other types of bitmaps, it may actually be used as a part of the bitmap 220 SkPMColor* colors = NULL; 221 int blue, green, red; 222 if (colorCount) 223 { 224 colors = new SkPMColor[colorCount]; 225 for (int j = 0; j < colorCount; j++) 226 { 227 //should this be a function - maybe a #define? 228 blue = readByte(buf, begin + 4*j); 229 green = readByte(buf, begin + 4*j + 1); 230 red = readByte(buf, begin + 4*j + 2); 231 colors[j] = SkPackARGB32(0xFF, red & 0xFF, green & 0xFF, blue & 0xFF); 232 } 233 } 234 int bitWidth = w*bitCount; 235 int test = bitWidth & 0x1F; 236 int mask = -(((test >> 4) | (test >> 3) | (test >> 2) | (test >> 1) | test) & 0x1); //either 0xFFFFFFFF or 0 237 int lineBitWidth = (bitWidth & 0xFFFFFFE0) + (0x20 & mask); 238 int lineWidth = lineBitWidth/bitCount; 239 240 int xorOffset = begin + colorCount*4; //beginning of the color bitmap 241 //other read method means we will just be here already 242 int andOffset = xorOffset + ((lineWidth*h*bitCount) >> 3); 243 244 /*int */test = w & 0x1F; //the low 5 bits - we are rounding up to the next 32 (2^5) 245 /*int */mask = -(((test >> 4) | (test >> 3) | (test >> 2) | (test >> 1) | test) & 0x1); //either 0xFFFFFFFF or 0 246 int andLineWidth = (w & 0xFFFFFFE0) + (0x20 & mask); 247 //if we allow different Configs, everything is the same til here 248 //change the config, and use different address getter, and place index vs color, and add the color table 249 //FIXME: what is the tradeoff in size? 250 //if the andbitmap (mask) is all zeroes, then we can easily do an index bitmap 251 //however, with small images with large colortables, maybe it's better to still do argb_8888 252 253 bm->setInfo(SkImageInfo::MakeN32Premul(w, h), calculateRowBytesFor8888(w, bitCount)); 254 255 if (SkImageDecoder::kDecodeBounds_Mode == mode) { 256 delete[] colors; 257 return true; 258 } 259 260 if (!this->allocPixelRef(bm, NULL)) 261 { 262 delete[] colors; 263 return false; 264 } 265 266 SkAutoLockPixels alp(*bm); 267 268 for (int y = 0; y < h; y++) 269 { 270 for (int x = 0; x < w; x++) 271 { 272 //U32* address = bm->getAddr32(x, y); 273 274 //check the alpha bit first, but pass it along to the function to figure out how to deal with it 275 int andPixelNo = andLineWidth*(h-y-1)+x; 276 //only need to get a new alphaByte when x %8 == 0 277 //but that introduces an if and a mod - probably much slower 278 //that's ok, it's just a read of an array, not a stream 279 int alphaByte = readByte(buf, andOffset + (andPixelNo >> 3)); 280 int shift = 7 - (andPixelNo & 0x7); 281 int m = 1 << shift; 282 283 int pixelNo = lineWidth*(h-y-1)+x; 284 placePixel(pixelNo, buf, xorOffset, x, y, w, bm, alphaByte, m, shift, colors); 285 286 } 287 } 288 289 delete [] colors; 290 //ensure we haven't read off the end? 291 //of course this doesn't help us if the andOffset was a lie... 292 //return andOffset + (andLineWidth >> 3) <= length; 293 return true; 294 } //onDecode 295 296 //function to place the pixel, determined by the bitCount 297 static void editPixelBit1(const int pixelNo, const unsigned char* buf, 298 const int xorOffset, int& x, int y, const int w, 299 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors) 300 { 301 // note that this should be the same as/similar to the AND bitmap 302 SkPMColor* address = bm->getAddr32(x,y); 303 int byte = readByte(buf, xorOffset + (pixelNo >> 3)); 304 int colorBit; 305 int alphaBit; 306 // Read all of the bits in this byte. 307 int i = x + 8; 308 // Pin to the width so we do not write outside the bounds of 309 // our color table. 310 i = i > w ? w : i; 311 // While loop to check all 8 bits individually. 312 while (x < i) 313 { 314 315 colorBit = (byte & m) >> shift; 316 alphaBit = (alphaByte & m) >> shift; 317 *address = (alphaBit-1)&(colors[colorBit]); 318 x++; 319 // setup for the next pixel 320 address = address + 1; 321 m = m >> 1; 322 shift -= 1; 323 } 324 x--; 325 } 326 static void editPixelBit4(const int pixelNo, const unsigned char* buf, 327 const int xorOffset, int& x, int y, const int w, 328 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors) 329 { 330 SkPMColor* address = bm->getAddr32(x, y); 331 int byte = readByte(buf, xorOffset + (pixelNo >> 1)); 332 int pixel = (byte >> 4) & 0xF; 333 int alphaBit = (alphaByte & m) >> shift; 334 *address = (alphaBit-1)&(colors[pixel]); 335 x++; 336 //if w is odd, x may be the same as w, which means we are writing to an unused portion of the bitmap 337 //but that's okay, since i've added an extra rowByte for just this purpose 338 address = address + 1; 339 pixel = byte & 0xF; 340 m = m >> 1; 341 alphaBit = (alphaByte & m) >> (shift-1); 342 //speed up trick here 343 *address = (alphaBit-1)&(colors[pixel]); 344 } 345 346 static void editPixelBit8(const int pixelNo, const unsigned char* buf, 347 const int xorOffset, int& x, int y, const int w, 348 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors) 349 { 350 SkPMColor* address = bm->getAddr32(x, y); 351 int pixel = readByte(buf, xorOffset + pixelNo); 352 int alphaBit = (alphaByte & m) >> shift; 353 *address = (alphaBit-1)&(colors[pixel]); 354 } 355 356 static void editPixelBit24(const int pixelNo, const unsigned char* buf, 357 const int xorOffset, int& x, int y, const int w, 358 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors) 359 { 360 SkPMColor* address = bm->getAddr32(x, y); 361 int blue = readByte(buf, xorOffset + 3*pixelNo); 362 int green = readByte(buf, xorOffset + 3*pixelNo + 1); 363 int red = readByte(buf, xorOffset + 3*pixelNo + 2); 364 int alphaBit = (alphaByte & m) >> shift; 365 //alphaBit == 1 => alpha = 0 366 int alpha = (alphaBit-1) & 0xFF; 367 *address = SkPreMultiplyARGB(alpha, red, green, blue); 368 } 369 370 static void editPixelBit32(const int pixelNo, const unsigned char* buf, 371 const int xorOffset, int& x, int y, const int w, 372 SkBitmap* bm, int alphaByte, int m, int shift, SkPMColor* colors) 373 { 374 SkPMColor* address = bm->getAddr32(x, y); 375 int blue = readByte(buf, xorOffset + 4*pixelNo); 376 int green = readByte(buf, xorOffset + 4*pixelNo + 1); 377 int red = readByte(buf, xorOffset + 4*pixelNo + 2); 378 int alphaBit = (alphaByte & m) >> shift; 379 #if 1 // don't trust the alphaBit for 32bit images <mrr> 380 alphaBit = 0; 381 #endif 382 int alpha = readByte(buf, xorOffset + 4*pixelNo + 3) & ((alphaBit-1)&0xFF); 383 *address = SkPreMultiplyARGB(alpha, red, green, blue); 384 } 385 386 /////////////////////////////////////////////////////////////////////////////// 387 DEFINE_DECODER_CREATOR(ICOImageDecoder); 388 ///////////////////////////////////////////////////////////////////////////////////////// 389 390 static bool is_ico(SkStreamRewindable* stream) { 391 // Check to see if the first four bytes are 0,0,1,0 392 // FIXME: Is that required and sufficient? 393 SkAutoMalloc autoMal(4); 394 unsigned char* buf = (unsigned char*)autoMal.get(); 395 stream->read((void*)buf, 4); 396 int reserved = read2Bytes(buf, 0); 397 int type = read2Bytes(buf, 2); 398 if (reserved != 0 || type != 1) { 399 // This stream does not represent an ICO image. 400 return false; 401 } 402 return true; 403 } 404 405 static SkImageDecoder* sk_libico_dfactory(SkStreamRewindable* stream) { 406 if (is_ico(stream)) { 407 return SkNEW(SkICOImageDecoder); 408 } 409 return NULL; 410 } 411 412 static SkImageDecoder_DecodeReg gReg(sk_libico_dfactory); 413 414 static SkImageDecoder::Format get_format_ico(SkStreamRewindable* stream) { 415 if (is_ico(stream)) { 416 return SkImageDecoder::kICO_Format; 417 } 418 return SkImageDecoder::kUnknown_Format; 419 } 420 421 static SkImageDecoder_FormatReg gFormatReg(get_format_ico); 422