Modules/imageop.c

   1
   2 /* imageopmodule - Various operations on pictures */
   3
   4 #ifdef sun
   5 #define signed
   6 #endif
   7
   8 #include "Python.h"
   9
  10 #if SIZEOF_INT == 4
  11 typedef int Py_Int32;
  12 typedef unsigned int Py_UInt32;
  13 #else
  14 #if SIZEOF_LONG == 4
  15 typedef long Py_Int32;
  16 typedef unsigned long Py_UInt32;
  17 #else
  18 #error "No 4-byte integral type"
  19 #endif
  20 #endif
  21
  22 #define CHARP(cp, xmax, x, y) ((char *)(cp+y*xmax+x))
  23 #define SHORTP(cp, xmax, x, y) ((short *)(cp+2*(y*xmax+x)))
  24 #define LONGP(cp, xmax, x, y) ((Py_Int32 *)(cp+4*(y*xmax+x)))
  25
  26 static PyObject *ImageopError;
  27 static PyObject *ImageopDict;
  28
  29 /* If this function returns true (the default if anything goes wrong), we're
  30    behaving in a backward-compatible way with respect to how multi-byte pixels
  31    are stored in the strings.  The code in this module was originally written
  32    for an SGI which is a big-endian system, and so the old code assumed that
  33    4-byte integers hold the R, G, and B values in a particular order.
  34    However, on little-endian systems the order is reversed, and so not
  35    actually compatible with what gl.lrectwrite and imgfile expect.
  36    (gl.lrectwrite and imgfile are also SGI-specific, however, it is
  37    conceivable that the data handled here comes from or goes to an SGI or that
  38    it is otherwise used in the expectation that the byte order in the strings
  39    is as specified.)
  40
  41    The function returns the value of the module variable
  42    "backward_compatible", or 1 if the variable does not exist or is not an
  43    int.
  44  */
  45
  46 static int
  47 imageop_backward_compatible(void)
  48 {
  49         static PyObject *bcos;
  50         PyObject *bco;
  51         long rc;
  52
  53         if (ImageopDict == NULL) /* "cannot happen" */
  54                 return 1;
  55         if (bcos == NULL) {
  56                 /* cache string object for future use */
  57                 bcos = PyString_FromString("backward_compatible");
  58                 if (bcos == NULL)
  59                         return 1;
  60         }
  61         bco = PyDict_GetItem(ImageopDict, bcos);
  62         if (bco == NULL)
  63                 return 1;
  64         if (!PyInt_Check(bco))
  65                 return 1;
  66         rc = PyInt_AsLong(bco);
  67         if (PyErr_Occurred()) {
  68                 /* not an integer, or too large, or something */
  69                 PyErr_Clear();
  70                 rc = 1;
  71         }
  72         return rc != 0;         /* convert to values 0, 1 */
  73 }
  74
  75 static PyObject *
  76 imageop_crop(PyObject *self, PyObject *args)
  77 {
  78         char *cp, *ncp;
  79         short *nsp;
  80         Py_Int32 *nlp;
  81         int len, size, x, y, newx1, newx2, newy1, newy2;
  82         int ix, iy, xstep, ystep;
  83         PyObject *rv;
  84
  85         if ( !PyArg_ParseTuple(args, "s#iiiiiii", &cp, &len, &size, &x, &y,
  86                           &newx1, &newy1, &newx2, &newy2) )
  87                 return 0;
  88
  89         if ( size != 1 && size != 2 && size != 4 ) {
  90                 PyErr_SetString(ImageopError, "Size should be 1, 2 or 4");
  91                 return 0;
  92         }
  93         if ( len != size*x*y ) {
  94                 PyErr_SetString(ImageopError, "String has incorrect length");
  95                 return 0;
  96         }
  97         xstep = (newx1 < newx2)? 1 : -1;
  98         ystep = (newy1 < newy2)? 1 : -1;
  99
 100         rv = PyString_FromStringAndSize(NULL,
 101                              (abs(newx2-newx1)+1)*(abs(newy2-newy1)+1)*size);
 102         if ( rv == 0 )
 103                 return 0;
 104         ncp = (char *)PyString_AsString(rv);
 105         nsp = (short *)ncp;
 106         nlp = (Py_Int32 *)ncp;
 107         newy2 += ystep;
 108         newx2 += xstep;
 109         for( iy = newy1; iy != newy2; iy+=ystep ) {
 110                 for ( ix = newx1; ix != newx2; ix+=xstep ) {
 111                         if ( iy < 0 || iy >= y || ix < 0 || ix >= x ) {
 112                                 if ( size == 1 )
 113                                         *ncp++ = 0;
 114                                 else
 115                                         *nlp++ = 0;
 116                         } else {
 117                                 if ( size == 1 )
 118                                         *ncp++ = *CHARP(cp, x, ix, iy);
 119                                 else if ( size == 2 )
 120                                         *nsp++ = *SHORTP(cp, x, ix, iy);
 121                                 else
 122                                         *nlp++ = *LONGP(cp, x, ix, iy);
 123                         }
 124                 }
 125         }
 126         return rv;
 127 }
 128
 129 static PyObject *
 130 imageop_scale(PyObject *self, PyObject *args)
 131 {
 132         char *cp, *ncp;
 133         short *nsp;
 134         Py_Int32 *nlp;
 135         int len, size, x, y, newx, newy;
 136         int ix, iy;
 137         int oix, oiy;
 138         PyObject *rv;
 139
 140         if ( !PyArg_ParseTuple(args, "s#iiiii",
 141                           &cp, &len, &size, &x, &y, &newx, &newy) )
 142                 return 0;
 143
 144         if ( size != 1 && size != 2 && size != 4 ) {
 145                 PyErr_SetString(ImageopError, "Size should be 1, 2 or 4");
 146                 return 0;
 147         }
 148         if ( len != size*x*y ) {
 149                 PyErr_SetString(ImageopError, "String has incorrect length");
 150                 return 0;
 151         }
 152
 153         rv = PyString_FromStringAndSize(NULL, newx*newy*size);
 154         if ( rv == 0 )
 155                 return 0;
 156         ncp = (char *)PyString_AsString(rv);
 157         nsp = (short *)ncp;
 158         nlp = (Py_Int32 *)ncp;
 159         for( iy = 0; iy < newy; iy++ ) {
 160                 for ( ix = 0; ix < newx; ix++ ) {
 161                         oix = ix * x / newx;
 162                         oiy = iy * y / newy;
 163                         if ( size == 1 )
 164                                 *ncp++ = *CHARP(cp, x, oix, oiy);
 165                         else if ( size == 2 )
 166                                 *nsp++ = *SHORTP(cp, x, oix, oiy);
 167                         else
 168                                 *nlp++ = *LONGP(cp, x, oix, oiy);
 169                 }
 170         }
 171         return rv;
 172 }
 173
 174 /* Note: this routine can use a bit of optimizing */
 175
 176 static PyObject *
 177 imageop_tovideo(PyObject *self, PyObject *args)
 178 {
 179         int maxx, maxy, x, y, len;
 180         int i;
 181         unsigned char *cp, *ncp;
 182         int width;
 183         PyObject *rv;
 184
 185
 186         if ( !PyArg_ParseTuple(args, "s#iii", &cp, &len, &width, &maxx, &maxy) )
 187                 return 0;
 188
 189         if ( width != 1 && width != 4 ) {
 190                 PyErr_SetString(ImageopError, "Size should be 1 or 4");
 191                 return 0;
 192         }
 193         if ( maxx*maxy*width != len ) {
 194                 PyErr_SetString(ImageopError, "String has incorrect length");
 195                 return 0;
 196         }
 197
 198         rv = PyString_FromStringAndSize(NULL, len);
 199         if ( rv == 0 )
 200                 return 0;
 201         ncp = (unsigned char *)PyString_AsString(rv);
 202
 203         if ( width == 1 ) {
 204                 memcpy(ncp, cp, maxx);          /* Copy first line */
 205                 ncp += maxx;
 206                 for (y=1; y<maxy; y++) {        /* Interpolate other lines */
 207                         for(x=0; x<maxx; x++) {
 208                                 i = y*maxx + x;
 209                                 *ncp++ = ((int)cp[i] + (int)cp[i-maxx]) >> 1;
 210                         }
 211                 }
 212         } else {
 213                 memcpy(ncp, cp, maxx*4);                /* Copy first line */
 214                 ncp += maxx*4;
 215                 for (y=1; y<maxy; y++) {        /* Interpolate other lines */
 216                         for(x=0; x<maxx; x++) {
 217                                 i = (y*maxx + x)*4 + 1;
 218                                 *ncp++ = 0;     /* Skip alfa comp */
 219                                 *ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;
 220                                 i++;
 221                                 *ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;
 222                                 i++;
 223                                 *ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;
 224                         }
 225                 }
 226         }
 227         return rv;
 228 }
 229
 230 static PyObject *
 231 imageop_grey2mono(PyObject *self, PyObject *args)
 232 {
 233         int tres, x, y, len;
 234         unsigned char *cp, *ncp;
 235         unsigned char ovalue;
 236         PyObject *rv;
 237         int i, bit;
 238
 239
 240         if ( !PyArg_ParseTuple(args, "s#iii", &cp, &len, &x, &y, &tres) )
 241                 return 0;
 242
 243         if ( x*y != len ) {
 244                 PyErr_SetString(ImageopError, "String has incorrect length");
 245                 return 0;
 246         }
 247
 248         rv = PyString_FromStringAndSize(NULL, (len+7)/8);
 249         if ( rv == 0 )
 250                 return 0;
 251         ncp = (unsigned char *)PyString_AsString(rv);
 252
 253         bit = 0x80;
 254         ovalue = 0;
 255         for ( i=0; i < len; i++ ) {
 256                 if ( (int)cp[i] > tres )
 257                         ovalue |= bit;
 258                 bit >>= 1;
 259                 if ( bit == 0 ) {
 260                         *ncp++ = ovalue;
 261                         bit = 0x80;
 262                         ovalue = 0;
 263                 }
 264         }
 265         if ( bit != 0x80 )
 266                 *ncp++ = ovalue;
 267         return rv;
 268 }
 269
 270 static PyObject *
 271 imageop_grey2grey4(PyObject *self, PyObject *args)
 272 {
 273         int x, y, len;
 274         unsigned char *cp, *ncp;
 275         unsigned char ovalue;
 276         PyObject *rv;
 277         int i;
 278         int pos;
 279
 280
 281         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 282                 return 0;
 283
 284         if ( x*y != len ) {
 285                 PyErr_SetString(ImageopError, "String has incorrect length");
 286                 return 0;
 287         }
 288
 289         rv = PyString_FromStringAndSize(NULL, (len+1)/2);
 290         if ( rv == 0 )
 291                 return 0;
 292         ncp = (unsigned char *)PyString_AsString(rv);
 293         pos = 0;
 294         ovalue = 0;
 295         for ( i=0; i < len; i++ ) {
 296                 ovalue |= ((int)cp[i] & 0xf0) >> pos;
 297                 pos += 4;
 298                 if ( pos == 8 ) {
 299                         *ncp++ = ovalue;
 300                         ovalue = 0;
 301                         pos = 0;
 302                 }
 303         }
 304         if ( pos != 0 )
 305                 *ncp++ = ovalue;
 306         return rv;
 307 }
 308
 309 static PyObject *
 310 imageop_grey2grey2(PyObject *self, PyObject *args)
 311 {
 312         int x, y, len;
 313         unsigned char *cp, *ncp;
 314         unsigned char ovalue;
 315         PyObject *rv;
 316         int i;
 317         int pos;
 318
 319
 320         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 321                 return 0;
 322
 323         if ( x*y != len ) {
 324                 PyErr_SetString(ImageopError, "String has incorrect length");
 325                 return 0;
 326         }
 327
 328         rv = PyString_FromStringAndSize(NULL, (len+3)/4);
 329         if ( rv == 0 )
 330                 return 0;
 331         ncp = (unsigned char *)PyString_AsString(rv);
 332         pos = 0;
 333         ovalue = 0;
 334         for ( i=0; i < len; i++ ) {
 335                 ovalue |= ((int)cp[i] & 0xc0) >> pos;
 336                 pos += 2;
 337                 if ( pos == 8 ) {
 338                         *ncp++ = ovalue;
 339                         ovalue = 0;
 340                         pos = 0;
 341                 }
 342         }
 343         if ( pos != 0 )
 344                 *ncp++ = ovalue;
 345         return rv;
 346 }
 347
 348 static PyObject *
 349 imageop_dither2mono(PyObject *self, PyObject *args)
 350 {
 351         int sum, x, y, len;
 352         unsigned char *cp, *ncp;
 353         unsigned char ovalue;
 354         PyObject *rv;
 355         int i, bit;
 356
 357
 358         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 359                 return 0;
 360
 361         if ( x*y != len ) {
 362                 PyErr_SetString(ImageopError, "String has incorrect length");
 363                 return 0;
 364         }
 365
 366         rv = PyString_FromStringAndSize(NULL, (len+7)/8);
 367         if ( rv == 0 )
 368                 return 0;
 369         ncp = (unsigned char *)PyString_AsString(rv);
 370
 371         bit = 0x80;
 372         ovalue = 0;
 373         sum = 0;
 374         for ( i=0; i < len; i++ ) {
 375                 sum += cp[i];
 376                 if ( sum >= 256 ) {
 377                         sum -= 256;
 378                         ovalue |= bit;
 379                 }
 380                 bit >>= 1;
 381                 if ( bit == 0 ) {
 382                         *ncp++ = ovalue;
 383                         bit = 0x80;
 384                         ovalue = 0;
 385                 }
 386         }
 387         if ( bit != 0x80 )
 388                 *ncp++ = ovalue;
 389         return rv;
 390 }
 391
 392 static PyObject *
 393 imageop_dither2grey2(PyObject *self, PyObject *args)
 394 {
 395         int x, y, len;
 396         unsigned char *cp, *ncp;
 397         unsigned char ovalue;
 398         PyObject *rv;
 399         int i;
 400         int pos;
 401         int sum = 0, nvalue;
 402
 403
 404         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 405                 return 0;
 406
 407         if ( x*y != len ) {
 408                 PyErr_SetString(ImageopError, "String has incorrect length");
 409                 return 0;
 410         }
 411
 412         rv = PyString_FromStringAndSize(NULL, (len+3)/4);
 413         if ( rv == 0 )
 414                 return 0;
 415         ncp = (unsigned char *)PyString_AsString(rv);
 416         pos = 1;
 417         ovalue = 0;
 418         for ( i=0; i < len; i++ ) {
 419                 sum += cp[i];
 420                 nvalue = sum & 0x180;
 421                 sum -= nvalue;
 422                 ovalue |= nvalue >> pos;
 423                 pos += 2;
 424                 if ( pos == 9 ) {
 425                         *ncp++ = ovalue;
 426                         ovalue = 0;
 427                         pos = 1;
 428                 }
 429         }
 430         if ( pos != 0 )
 431                 *ncp++ = ovalue;
 432         return rv;
 433 }
 434
 435 static PyObject *
 436 imageop_mono2grey(PyObject *self, PyObject *args)
 437 {
 438         int v0, v1, x, y, len, nlen;
 439         unsigned char *cp, *ncp;
 440         PyObject *rv;
 441         int i, bit;
 442
 443         if ( !PyArg_ParseTuple(args, "s#iiii", &cp, &len, &x, &y, &v0, &v1) )
 444                 return 0;
 445
 446         nlen = x*y;
 447         if ( (nlen+7)/8 != len ) {
 448                 PyErr_SetString(ImageopError, "String has incorrect length");
 449                 return 0;
 450         }
 451
 452         rv = PyString_FromStringAndSize(NULL, nlen);
 453         if ( rv == 0 )
 454                 return 0;
 455         ncp = (unsigned char *)PyString_AsString(rv);
 456
 457         bit = 0x80;
 458         for ( i=0; i < nlen; i++ ) {
 459                 if ( *cp & bit )
 460                         *ncp++ = v1;
 461                 else
 462                         *ncp++ = v0;
 463                 bit >>= 1;
 464                 if ( bit == 0 ) {
 465                         bit = 0x80;
 466                         cp++;
 467                 }
 468         }
 469         return rv;
 470 }
 471
 472 static PyObject *
 473 imageop_grey22grey(PyObject *self, PyObject *args)
 474 {
 475         int x, y, len, nlen;
 476         unsigned char *cp, *ncp;
 477         PyObject *rv;
 478         int i, pos, value = 0, nvalue;
 479
 480         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 481                 return 0;
 482
 483         nlen = x*y;
 484         if ( (nlen+3)/4 != len ) {
 485                 PyErr_SetString(ImageopError, "String has incorrect length");
 486                 return 0;
 487         }
 488
 489         rv = PyString_FromStringAndSize(NULL, nlen);
 490         if ( rv == 0 )
 491                 return 0;
 492         ncp = (unsigned char *)PyString_AsString(rv);
 493
 494         pos = 0;
 495         for ( i=0; i < nlen; i++ ) {
 496                 if ( pos == 0 ) {
 497                         value = *cp++;
 498                         pos = 8;
 499                 }
 500                 pos -= 2;
 501                 nvalue = (value >> pos) & 0x03;
 502                 *ncp++ = nvalue | (nvalue << 2) |
 503                          (nvalue << 4) | (nvalue << 6);
 504         }
 505         return rv;
 506 }
 507
 508 static PyObject *
 509 imageop_grey42grey(PyObject *self, PyObject *args)
 510 {
 511         int x, y, len, nlen;
 512         unsigned char *cp, *ncp;
 513         PyObject *rv;
 514         int i, pos, value = 0, nvalue;
 515
 516         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 517                 return 0;
 518
 519         nlen = x*y;
 520         if ( (nlen+1)/2 != len ) {
 521                 PyErr_SetString(ImageopError, "String has incorrect length");
 522                 return 0;
 523         }
 524
 525         rv = PyString_FromStringAndSize(NULL, nlen);
 526         if ( rv == 0 )
 527                 return 0;
 528         ncp = (unsigned char *)PyString_AsString(rv);
 529
 530         pos = 0;
 531         for ( i=0; i < nlen; i++ ) {
 532                 if ( pos == 0 ) {
 533                         value = *cp++;
 534                         pos = 8;
 535                 }
 536                 pos -= 4;
 537                 nvalue = (value >> pos) & 0x0f;
 538                 *ncp++ = nvalue | (nvalue << 4);
 539         }
 540         return rv;
 541 }
 542
 543 static PyObject *
 544 imageop_rgb2rgb8(PyObject *self, PyObject *args)
 545 {
 546         int x, y, len, nlen;
 547         unsigned char *cp;
 548         unsigned char *ncp;
 549         PyObject *rv;
 550         int i, r, g, b;
 551         int backward_compatible = imageop_backward_compatible();
 552
 553         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 554                 return 0;
 555
 556         nlen = x*y;
 557         if ( nlen*4 != len ) {
 558                 PyErr_SetString(ImageopError, "String has incorrect length");
 559                 return 0;
 560         }
 561
 562         rv = PyString_FromStringAndSize(NULL, nlen);
 563         if ( rv == 0 )
 564                 return 0;
 565         ncp = (unsigned char *)PyString_AsString(rv);
 566
 567         for ( i=0; i < nlen; i++ ) {
 568                 /* Bits in source: aaaaaaaa BBbbbbbb GGGggggg RRRrrrrr */
 569                 if (backward_compatible) {
 570                         Py_UInt32 value = * (Py_UInt32 *) cp;
 571                         cp += 4;
 572                         r = (int) ((value & 0xff) / 255. * 7. + .5);
 573                         g = (int) (((value >> 8) & 0xff) / 255. * 7. + .5);
 574                         b = (int) (((value >> 16) & 0xff) / 255. * 3. + .5);
 575                 } else {
 576                         cp++;           /* skip alpha channel */
 577                         b = (int) (*cp++ / 255. * 3. + .5);
 578                         g = (int) (*cp++ / 255. * 7. + .5);
 579                         r = (int) (*cp++ / 255. * 7. + .5);
 580                 }
 581                 *ncp++ = (unsigned char)((r<<5) | (b<<3) | g);
 582         }
 583         return rv;
 584 }
 585
 586 static PyObject *
 587 imageop_rgb82rgb(PyObject *self, PyObject *args)
 588 {
 589         int x, y, len, nlen;
 590         unsigned char *cp;
 591         unsigned char *ncp;
 592         PyObject *rv;
 593         int i, r, g, b;
 594         unsigned char value;
 595         int backward_compatible = imageop_backward_compatible();
 596
 597         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 598                 return 0;
 599
 600         nlen = x*y;
 601         if ( nlen != len ) {
 602                 PyErr_SetString(ImageopError, "String has incorrect length");
 603                 return 0;
 604         }
 605
 606         rv = PyString_FromStringAndSize(NULL, nlen*4);
 607         if ( rv == 0 )
 608                 return 0;
 609         ncp = (unsigned char *)PyString_AsString(rv);
 610
 611         for ( i=0; i < nlen; i++ ) {
 612                 /* Bits in source: RRRBBGGG
 613                 ** Red and Green are multiplied by 36.5, Blue by 85
 614                 */
 615                 value = *cp++;
 616                 r = (value >> 5) & 7;
 617                 g = (value     ) & 7;
 618                 b = (value >> 3) & 3;
 619                 r = (r<<5) | (r<<3) | (r>>1);
 620                 g = (g<<5) | (g<<3) | (g>>1);
 621                 b = (b<<6) | (b<<4) | (b<<2) | b;
 622                 if (backward_compatible) {
 623                         Py_UInt32 nvalue = r | (g<<8) | (b<<16);
 624                         * (Py_UInt32 *) ncp = nvalue;
 625                         ncp += 4;
 626                 } else {
 627                         *ncp++ = 0;
 628                         *ncp++ = b;
 629                         *ncp++ = g;
 630                         *ncp++ = r;
 631                 }
 632         }
 633         return rv;
 634 }
 635
 636 static PyObject *
 637 imageop_rgb2grey(PyObject *self, PyObject *args)
 638 {
 639         int x, y, len, nlen;
 640         unsigned char *cp;
 641         unsigned char *ncp;
 642         PyObject *rv;
 643         int i, r, g, b;
 644         int nvalue;
 645         int backward_compatible = imageop_backward_compatible();
 646
 647         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 648                 return 0;
 649
 650         nlen = x*y;
 651         if ( nlen*4 != len ) {
 652                 PyErr_SetString(ImageopError, "String has incorrect length");
 653                 return 0;
 654         }
 655
 656         rv = PyString_FromStringAndSize(NULL, nlen);
 657         if ( rv == 0 )
 658                 return 0;
 659         ncp = (unsigned char *)PyString_AsString(rv);
 660
 661         for ( i=0; i < nlen; i++ ) {
 662                 if (backward_compatible) {
 663                         Py_UInt32 value = * (Py_UInt32 *) cp;
 664                         cp += 4;
 665                         r = (int) ((value & 0xff) / 255. * 7. + .5);
 666                         g = (int) (((value >> 8) & 0xff) / 255. * 7. + .5);
 667                         b = (int) (((value >> 16) & 0xff) / 255. * 3. + .5);
 668                 } else {
 669                         cp++;           /* skip alpha channel */
 670                         b = *cp++;
 671                         g = *cp++;
 672                         r = *cp++;
 673                 }
 674                 nvalue = (int)(0.30*r + 0.59*g + 0.11*b);
 675                 if ( nvalue > 255 ) nvalue = 255;
 676                 *ncp++ = (unsigned char)nvalue;
 677         }
 678         return rv;
 679 }
 680
 681 static PyObject *
 682 imageop_grey2rgb(PyObject *self, PyObject *args)
 683 {
 684         int x, y, len, nlen;
 685         unsigned char *cp;
 686         unsigned char *ncp;
 687         PyObject *rv;
 688         int i;
 689         unsigned char value;
 690         int backward_compatible = imageop_backward_compatible();
 691
 692         if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 693                 return 0;
 694
 695         nlen = x*y;
 696         if ( nlen != len ) {
 697                 PyErr_SetString(ImageopError, "String has incorrect length");
 698                 return 0;
 699         }
 700
 701         rv = PyString_FromStringAndSize(NULL, nlen*4);
 702         if ( rv == 0 )
 703                 return 0;
 704         ncp = (unsigned char *)PyString_AsString(rv);
 705
 706         for ( i=0; i < nlen; i++ ) {
 707                 value = *cp++;
 708                 if (backward_compatible) {
 709                         * (Py_UInt32 *) ncp = (Py_UInt32) value | ((Py_UInt32) value << 8 ) | ((Py_UInt32) value << 16);
 710                         ncp += 4;
 711                 } else {
 712                         *ncp++ = 0;
 713                         *ncp++ = value;
 714                         *ncp++ = value;
 715                         *ncp++ = value;
 716                 }
 717         }
 718         return rv;
 719 }
 720
 721 /*
 722 static object *
 723 imageop_mul(object *self, object *args)
 724 {
 725         char *cp, *ncp;
 726         int len, size, x, y;
 727         object *rv;
 728         int i;
 729
 730         if ( !getargs(args, "(s#iii)", &cp, &len, &size, &x, &y) )
 731                 return 0;
 732
 733         if ( size != 1 && size != 4 ) {
 734                 err_setstr(ImageopError, "Size should be 1 or 4");
 735                 return 0;
 736         }
 737         if ( len != size*x*y ) {
 738                 err_setstr(ImageopError, "String has incorrect length");
 739                 return 0;
 740         }
 741
 742         rv = newsizedstringobject(NULL, XXXX);
 743         if ( rv == 0 )
 744                 return 0;
 745         ncp = (char *)getstringvalue(rv);
 746
 747
 748         for ( i=0; i < len; i += size ) {
 749         }
 750         return rv;
 751 }
 752 */
 753
 754 static PyMethodDef imageop_methods[] = {
 755         { "crop",               imageop_crop, METH_VARARGS },
 756         { "scale",              imageop_scale, METH_VARARGS },
 757         { "grey2mono",          imageop_grey2mono, METH_VARARGS },
 758         { "grey2grey2",         imageop_grey2grey2, METH_VARARGS },
 759         { "grey2grey4",         imageop_grey2grey4, METH_VARARGS },
 760         { "dither2mono",        imageop_dither2mono, METH_VARARGS },
 761         { "dither2grey2",       imageop_dither2grey2, METH_VARARGS },
 762         { "mono2grey",          imageop_mono2grey, METH_VARARGS },
 763         { "grey22grey",         imageop_grey22grey, METH_VARARGS },
 764         { "grey42grey",         imageop_grey42grey, METH_VARARGS },
 765         { "tovideo",            imageop_tovideo, METH_VARARGS },
 766         { "rgb2rgb8",           imageop_rgb2rgb8, METH_VARARGS },
 767         { "rgb82rgb",           imageop_rgb82rgb, METH_VARARGS },
 768         { "rgb2grey",           imageop_rgb2grey, METH_VARARGS },
 769         { "grey2rgb",           imageop_grey2rgb, METH_VARARGS },
 770         { 0,                    0 }
 771 };
 772
 773
 774 PyMODINIT_FUNC
 775 initimageop(void)
 776 {
 777         PyObject *m;
 778         m = Py_InitModule("imageop", imageop_methods);
 779         ImageopDict = PyModule_GetDict(m);
 780         ImageopError = PyErr_NewException("imageop.error", NULL, NULL);
 781         if (ImageopError != NULL)
 782                 PyDict_SetItemString(ImageopDict, "error", ImageopError);
 783 }