dlls/windowscodecs/libpng.c

   1 /*
   2  * Copyright 2016 Dmitry Timoshkov
   3  * Copyright 2020 Esme Povirk
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  18  */
  19
  20 #include <stdarg.h>
  21 #include <png.h>
  22
  23 #define NONAMELESSUNION
  24
  25 #include "ntstatus.h"
  26 #define WIN32_NO_STATUS
  27 #include "windef.h"
  28 #include "winternl.h"
  29 #include "winbase.h"
  30 #include "objbase.h"
  31
  32 #include "wincodecs_private.h"
  33
  34 #include "wine/debug.h"
  35
  36 WINE_DEFAULT_DEBUG_CHANNEL(wincodecs);
  37
  38 struct png_decoder
  39 {
  40     struct decoder decoder;
  41     IStream *stream;
  42     struct decoder_frame decoder_frame;
  43     UINT stride;
  44     BYTE *image_bits;
  45     BYTE *color_profile;
  46     DWORD color_profile_len;
  47 };
  48
  49 static inline struct png_decoder *impl_from_decoder(struct decoder* iface)
  50 {
  51     return CONTAINING_RECORD(iface, struct png_decoder, decoder);
  52 }
  53
  54 static void user_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
  55 {
  56     IStream *stream = png_get_io_ptr(png_ptr);
  57     HRESULT hr;
  58     ULONG bytesread;
  59
  60     hr = stream_read(stream, data, length, &bytesread);
  61     if (FAILED(hr) || bytesread != length)
  62     {
  63         png_error(png_ptr, "failed reading data");
  64     }
  65 }
  66
  67 static HRESULT CDECL png_decoder_initialize(struct decoder *iface, IStream *stream, struct decoder_stat *st)
  68 {
  69     struct png_decoder *This = impl_from_decoder(iface);
  70     png_structp png_ptr;
  71     png_infop info_ptr;
  72     HRESULT hr = E_FAIL;
  73     int color_type, bit_depth;
  74     png_bytep trans;
  75     int num_trans;
  76     png_uint_32 transparency;
  77     png_color_16p trans_values;
  78     png_uint_32 ret, xres, yres;
  79     int unit_type;
  80     png_colorp png_palette;
  81     int num_palette;
  82     int i;
  83     UINT image_size;
  84     png_bytep *row_pointers=NULL;
  85     png_charp cp_name;
  86     png_bytep cp_profile;
  87     png_uint_32 cp_len;
  88     int cp_compression;
  89
  90     png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  91     if (!png_ptr)
  92     {
  93         return E_FAIL;
  94     }
  95
  96     info_ptr = png_create_info_struct(png_ptr);
  97     if (!info_ptr)
  98     {
  99         png_destroy_read_struct(&png_ptr, NULL, NULL);
 100         return E_FAIL;
 101     }
 102
 103     /* set up setjmp/longjmp error handling */
 104     if (setjmp(png_jmpbuf(png_ptr)))
 105     {
 106         hr = WINCODEC_ERR_UNKNOWNIMAGEFORMAT;
 107         goto end;
 108     }
 109     png_set_crc_action(png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
 110     png_set_chunk_malloc_max(png_ptr, 0);
 111
 112     /* seek to the start of the stream */
 113     hr = stream_seek(stream, 0, STREAM_SEEK_SET, NULL);
 114     if (FAILED(hr))
 115     {
 116         goto end;
 117     }
 118
 119     /* set up custom i/o handling */
 120     png_set_read_fn(png_ptr, stream, user_read_data);
 121
 122     /* read the header */
 123     png_read_info(png_ptr, info_ptr);
 124
 125     /* choose a pixel format */
 126     color_type = png_get_color_type(png_ptr, info_ptr);
 127     bit_depth = png_get_bit_depth(png_ptr, info_ptr);
 128
 129     /* PNGs with bit-depth greater than 8 are network byte order. Windows does not expect this. */
 130     if (bit_depth > 8)
 131         png_set_swap(png_ptr);
 132
 133     /* check for color-keyed alpha */
 134     transparency = png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values);
 135     if (!transparency)
 136         num_trans = 0;
 137
 138     if (transparency && (color_type == PNG_COLOR_TYPE_RGB ||
 139         (color_type == PNG_COLOR_TYPE_GRAY && bit_depth == 16)))
 140     {
 141         /* expand to RGBA */
 142         if (color_type == PNG_COLOR_TYPE_GRAY)
 143             png_set_gray_to_rgb(png_ptr);
 144         png_set_tRNS_to_alpha(png_ptr);
 145         color_type = PNG_COLOR_TYPE_RGB_ALPHA;
 146     }
 147
 148     switch (color_type)
 149     {
 150     case PNG_COLOR_TYPE_GRAY_ALPHA:
 151         /* WIC does not support grayscale alpha formats so use RGBA */
 152         png_set_gray_to_rgb(png_ptr);
 153         /* fall through */
 154     case PNG_COLOR_TYPE_RGB_ALPHA:
 155         This->decoder_frame.bpp = bit_depth * 4;
 156         switch (bit_depth)
 157         {
 158         case 8:
 159             png_set_bgr(png_ptr);
 160             This->decoder_frame.pixel_format = GUID_WICPixelFormat32bppBGRA;
 161             break;
 162         case 16: This->decoder_frame.pixel_format = GUID_WICPixelFormat64bppRGBA; break;
 163         default:
 164             ERR("invalid RGBA bit depth: %i\n", bit_depth);
 165             hr = E_FAIL;
 166             goto end;
 167         }
 168         break;
 169     case PNG_COLOR_TYPE_GRAY:
 170         This->decoder_frame.bpp = bit_depth;
 171         if (!transparency)
 172         {
 173             switch (bit_depth)
 174             {
 175             case 1: This->decoder_frame.pixel_format = GUID_WICPixelFormatBlackWhite; break;
 176             case 2: This->decoder_frame.pixel_format = GUID_WICPixelFormat2bppGray; break;
 177             case 4: This->decoder_frame.pixel_format = GUID_WICPixelFormat4bppGray; break;
 178             case 8: This->decoder_frame.pixel_format = GUID_WICPixelFormat8bppGray; break;
 179             case 16: This->decoder_frame.pixel_format = GUID_WICPixelFormat16bppGray; break;
 180             default:
 181                 ERR("invalid grayscale bit depth: %i\n", bit_depth);
 182                 hr = E_FAIL;
 183                 goto end;
 184             }
 185             break;
 186         }
 187         /* else fall through */
 188     case PNG_COLOR_TYPE_PALETTE:
 189         This->decoder_frame.bpp = bit_depth;
 190         switch (bit_depth)
 191         {
 192         case 1: This->decoder_frame.pixel_format = GUID_WICPixelFormat1bppIndexed; break;
 193         case 2: This->decoder_frame.pixel_format = GUID_WICPixelFormat2bppIndexed; break;
 194         case 4: This->decoder_frame.pixel_format = GUID_WICPixelFormat4bppIndexed; break;
 195         case 8: This->decoder_frame.pixel_format = GUID_WICPixelFormat8bppIndexed; break;
 196         default:
 197             ERR("invalid indexed color bit depth: %i\n", bit_depth);
 198             hr = E_FAIL;
 199             goto end;
 200         }
 201         break;
 202     case PNG_COLOR_TYPE_RGB:
 203         This->decoder_frame.bpp = bit_depth * 3;
 204         switch (bit_depth)
 205         {
 206         case 8:
 207             png_set_bgr(png_ptr);
 208             This->decoder_frame.pixel_format = GUID_WICPixelFormat24bppBGR;
 209             break;
 210         case 16: This->decoder_frame.pixel_format = GUID_WICPixelFormat48bppRGB; break;
 211         default:
 212             ERR("invalid RGB color bit depth: %i\n", bit_depth);
 213             hr = E_FAIL;
 214             goto end;
 215         }
 216         break;
 217     default:
 218         ERR("invalid color type %i\n", color_type);
 219         hr = E_FAIL;
 220         goto end;
 221     }
 222
 223     This->decoder_frame.width = png_get_image_width(png_ptr, info_ptr);
 224     This->decoder_frame.height = png_get_image_height(png_ptr, info_ptr);
 225
 226     ret = png_get_pHYs(png_ptr, info_ptr, &xres, &yres, &unit_type);
 227
 228     if (ret && unit_type == PNG_RESOLUTION_METER)
 229     {
 230         This->decoder_frame.dpix = xres * 0.0254;
 231         This->decoder_frame.dpiy = yres * 0.0254;
 232     }
 233     else
 234     {
 235         WARN("no pHYs block present\n");
 236         This->decoder_frame.dpix = This->decoder_frame.dpiy = 96.0;
 237     }
 238
 239     ret = png_get_iCCP(png_ptr, info_ptr, &cp_name, &cp_compression, &cp_profile, &cp_len);
 240     if (ret)
 241     {
 242         This->decoder_frame.num_color_contexts = 1;
 243         This->color_profile_len = cp_len;
 244         This->color_profile = malloc(cp_len);
 245         if (!This->color_profile)
 246         {
 247             hr = E_OUTOFMEMORY;
 248             goto end;
 249         }
 250         memcpy(This->color_profile, cp_profile, cp_len);
 251     }
 252     else
 253         This->decoder_frame.num_color_contexts = 0;
 254
 255     if (color_type == PNG_COLOR_TYPE_PALETTE)
 256     {
 257         ret = png_get_PLTE(png_ptr, info_ptr, &png_palette, &num_palette);
 258         if (!ret)
 259         {
 260             ERR("paletted image with no PLTE chunk\n");
 261             hr = E_FAIL;
 262             goto end;
 263         }
 264
 265         if (num_palette > 256)
 266         {
 267             ERR("palette has %i colors?!\n", num_palette);
 268             hr = E_FAIL;
 269             goto end;
 270         }
 271
 272         This->decoder_frame.num_colors = num_palette;
 273         for (i=0; i<num_palette; i++)
 274         {
 275             BYTE alpha = (i < num_trans) ? trans[i] : 0xff;
 276             This->decoder_frame.palette[i] = (alpha << 24 |
 277                                               png_palette[i].red << 16|
 278                                               png_palette[i].green << 8|
 279                                               png_palette[i].blue);
 280         }
 281     }
 282     else if (color_type == PNG_COLOR_TYPE_GRAY && transparency && bit_depth <= 8) {
 283         num_palette = 1 << bit_depth;
 284
 285         This->decoder_frame.num_colors = num_palette;
 286         for (i=0; i<num_palette; i++)
 287         {
 288             BYTE alpha = (i == trans_values[0].gray) ? 0 : 0xff;
 289             BYTE val = i * 255 / (num_palette - 1);
 290             This->decoder_frame.palette[i] = (alpha << 24 | val << 16 | val << 8 | val);
 291         }
 292     }
 293     else
 294     {
 295         This->decoder_frame.num_colors = 0;
 296     }
 297
 298     This->stride = (This->decoder_frame.width * This->decoder_frame.bpp + 7) / 8;
 299     image_size = This->stride * This->decoder_frame.height;
 300
 301     This->image_bits = malloc(image_size);
 302     if (!This->image_bits)
 303     {
 304         hr = E_OUTOFMEMORY;
 305         goto end;
 306     }
 307
 308     row_pointers = malloc(sizeof(png_bytep)*This->decoder_frame.height);
 309     if (!row_pointers)
 310     {
 311         hr = E_OUTOFMEMORY;
 312         goto end;
 313     }
 314
 315     for (i=0; i<This->decoder_frame.height; i++)
 316         row_pointers[i] = This->image_bits + i * This->stride;
 317
 318     png_read_image(png_ptr, row_pointers);
 319
 320     free(row_pointers);
 321     row_pointers = NULL;
 322
 323     /* png_read_end intentionally not called to not seek to the end of the file */
 324
 325     st->flags = WICBitmapDecoderCapabilityCanDecodeAllImages |
 326                 WICBitmapDecoderCapabilityCanDecodeSomeImages |
 327                 WICBitmapDecoderCapabilityCanEnumerateMetadata;
 328     st->frame_count = 1;
 329
 330     This->stream = stream;
 331
 332     hr = S_OK;
 333
 334 end:
 335     png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 336     free(row_pointers);
 337     if (FAILED(hr))
 338     {
 339         free(This->image_bits);
 340         This->image_bits = NULL;
 341         free(This->color_profile);
 342         This->color_profile = NULL;
 343     }
 344     return hr;
 345 }
 346
 347 static HRESULT CDECL png_decoder_get_frame_info(struct decoder *iface, UINT frame, struct decoder_frame *info)
 348 {
 349     struct png_decoder *This = impl_from_decoder(iface);
 350     *info = This->decoder_frame;
 351     return S_OK;
 352 }
 353
 354 static HRESULT CDECL png_decoder_copy_pixels(struct decoder *iface, UINT frame,
 355     const WICRect *prc, UINT stride, UINT buffersize, BYTE *buffer)
 356 {
 357     struct png_decoder *This = impl_from_decoder(iface);
 358
 359     return copy_pixels(This->decoder_frame.bpp, This->image_bits,
 360         This->decoder_frame.width, This->decoder_frame.height, This->stride,
 361         prc, stride, buffersize, buffer);
 362 }
 363
 364 static HRESULT CDECL png_decoder_get_metadata_blocks(struct decoder* iface,
 365     UINT frame, UINT *count, struct decoder_block **blocks)
 366 {
 367     struct png_decoder *This = impl_from_decoder(iface);
 368     HRESULT hr;
 369     struct decoder_block *result = NULL;
 370     ULONGLONG seek;
 371     BYTE chunk_type[4];
 372     ULONG chunk_size;
 373     ULONGLONG chunk_start;
 374     ULONG metadata_blocks_size = 0;
 375
 376     seek = 8;
 377     *count = 0;
 378
 379     do
 380     {
 381         hr = stream_seek(This->stream, seek, STREAM_SEEK_SET, &chunk_start);
 382         if (FAILED(hr)) goto end;
 383
 384         hr = read_png_chunk(This->stream, chunk_type, NULL, &chunk_size);
 385         if (FAILED(hr)) goto end;
 386
 387         if (chunk_type[0] >= 'a' && chunk_type[0] <= 'z' &&
 388             memcmp(chunk_type, "tRNS", 4) && memcmp(chunk_type, "pHYs", 4))
 389         {
 390             /* This chunk is considered metadata. */
 391             if (*count == metadata_blocks_size)
 392             {
 393                 struct decoder_block *new_metadata_blocks;
 394                 ULONG new_metadata_blocks_size;
 395
 396                 new_metadata_blocks_size = 4 + metadata_blocks_size * 2;
 397                 new_metadata_blocks = RtlAllocateHeap(GetProcessHeap(), 0,
 398                     new_metadata_blocks_size * sizeof(*new_metadata_blocks));
 399
 400                 if (!new_metadata_blocks)
 401                 {
 402                     hr = E_OUTOFMEMORY;
 403                     goto end;
 404                 }
 405
 406                 memcpy(new_metadata_blocks, result,
 407                     *count * sizeof(*new_metadata_blocks));
 408
 409                 RtlFreeHeap(GetProcessHeap(), 0, result);
 410                 result = new_metadata_blocks;
 411                 metadata_blocks_size = new_metadata_blocks_size;
 412             }
 413
 414             result[*count].offset = chunk_start;
 415             result[*count].length = chunk_size + 12;
 416             result[*count].options = WICMetadataCreationAllowUnknown;
 417             (*count)++;
 418         }
 419
 420         seek = chunk_start + chunk_size + 12; /* skip data and CRC */
 421     } while (memcmp(chunk_type, "IEND", 4));
 422
 423 end:
 424     if (SUCCEEDED(hr))
 425     {
 426         *blocks = result;
 427     }
 428     else
 429     {
 430         *count = 0;
 431         *blocks = NULL;
 432         RtlFreeHeap(GetProcessHeap(), 0, result);
 433     }
 434     return hr;
 435 }
 436
 437 static HRESULT CDECL png_decoder_get_color_context(struct decoder* iface, UINT frame, UINT num,
 438     BYTE **data, DWORD *datasize)
 439 {
 440     struct png_decoder *This = impl_from_decoder(iface);
 441
 442     *data = RtlAllocateHeap(GetProcessHeap(), 0, This->color_profile_len);
 443     *datasize = This->color_profile_len;
 444
 445     if (!*data)
 446         return E_OUTOFMEMORY;
 447
 448     memcpy(*data, This->color_profile, This->color_profile_len);
 449
 450     return S_OK;
 451 }
 452
 453 static void CDECL png_decoder_destroy(struct decoder* iface)
 454 {
 455     struct png_decoder *This = impl_from_decoder(iface);
 456
 457     free(This->image_bits);
 458     free(This->color_profile);
 459     RtlFreeHeap(GetProcessHeap(), 0, This);
 460 }
 461
 462 static const struct decoder_funcs png_decoder_vtable = {
 463     png_decoder_initialize,
 464     png_decoder_get_frame_info,
 465     png_decoder_copy_pixels,
 466     png_decoder_get_metadata_blocks,
 467     png_decoder_get_color_context,
 468     png_decoder_destroy
 469 };
 470
 471 HRESULT CDECL png_decoder_create(struct decoder_info *info, struct decoder **result)
 472 {
 473     struct png_decoder *This;
 474
 475     This = RtlAllocateHeap(GetProcessHeap(), 0, sizeof(*This));
 476
 477     if (!This)
 478     {
 479         return E_OUTOFMEMORY;
 480     }
 481
 482     This->decoder.vtable = &png_decoder_vtable;
 483     This->image_bits = NULL;
 484     This->color_profile = NULL;
 485     *result = &This->decoder;
 486
 487     info->container_format = GUID_ContainerFormatPng;
 488     info->block_format = GUID_ContainerFormatPng;
 489     info->clsid = CLSID_WICPngDecoder;
 490
 491     return S_OK;
 492 }
 493
 494 struct png_pixelformat {
 495     const WICPixelFormatGUID *guid;
 496     UINT bpp;
 497     int bit_depth;
 498     int color_type;
 499     BOOL remove_filler;
 500     BOOL swap_rgb;
 501 };
 502
 503 static const struct png_pixelformat formats[] = {
 504     {&GUID_WICPixelFormat32bppBGRA, 32, 8, PNG_COLOR_TYPE_RGB_ALPHA, 0, 1},
 505     {&GUID_WICPixelFormat24bppBGR, 24, 8, PNG_COLOR_TYPE_RGB, 0, 1},
 506     {&GUID_WICPixelFormatBlackWhite, 1, 1, PNG_COLOR_TYPE_GRAY, 0, 0},
 507     {&GUID_WICPixelFormat2bppGray, 2, 2, PNG_COLOR_TYPE_GRAY, 0, 0},
 508     {&GUID_WICPixelFormat4bppGray, 4, 4, PNG_COLOR_TYPE_GRAY, 0, 0},
 509     {&GUID_WICPixelFormat8bppGray, 8, 8, PNG_COLOR_TYPE_GRAY, 0, 0},
 510     {&GUID_WICPixelFormat16bppGray, 16, 16, PNG_COLOR_TYPE_GRAY, 0, 0},
 511     {&GUID_WICPixelFormat32bppBGR, 32, 8, PNG_COLOR_TYPE_RGB, 1, 1},
 512     {&GUID_WICPixelFormat48bppRGB, 48, 16, PNG_COLOR_TYPE_RGB, 0, 0},
 513     {&GUID_WICPixelFormat64bppRGBA, 64, 16, PNG_COLOR_TYPE_RGB_ALPHA, 0, 0},
 514     {&GUID_WICPixelFormat1bppIndexed, 1, 1, PNG_COLOR_TYPE_PALETTE, 0, 0},
 515     {&GUID_WICPixelFormat2bppIndexed, 2, 2, PNG_COLOR_TYPE_PALETTE, 0, 0},
 516     {&GUID_WICPixelFormat4bppIndexed, 4, 4, PNG_COLOR_TYPE_PALETTE, 0, 0},
 517     {&GUID_WICPixelFormat8bppIndexed, 8, 8, PNG_COLOR_TYPE_PALETTE, 0, 0},
 518     {NULL},
 519 };
 520
 521 struct png_encoder
 522 {
 523     struct encoder encoder;
 524     IStream *stream;
 525     png_structp png_ptr;
 526     png_infop info_ptr;
 527     struct encoder_frame encoder_frame;
 528     const struct png_pixelformat *format;
 529     BYTE *data;
 530     UINT stride;
 531     UINT passes;
 532     UINT lines_written;
 533 };
 534
 535 static inline struct png_encoder *impl_from_encoder(struct encoder* iface)
 536 {
 537     return CONTAINING_RECORD(iface, struct png_encoder, encoder);
 538 }
 539
 540 static void user_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 541 {
 542     struct png_encoder *This = png_get_io_ptr(png_ptr);
 543     HRESULT hr;
 544     ULONG byteswritten;
 545
 546     hr = stream_write(This->stream, data, length, &byteswritten);
 547     if (FAILED(hr) || byteswritten != length)
 548     {
 549         png_error(png_ptr, "failed writing data");
 550     }
 551 }
 552
 553 static void user_flush(png_structp png_ptr)
 554 {
 555 }
 556
 557 static HRESULT CDECL png_encoder_initialize(struct encoder *encoder, IStream *stream)
 558 {
 559     struct png_encoder *This = impl_from_encoder(encoder);
 560
 561     TRACE("(%p,%p)\n", encoder, stream);
 562
 563     /* initialize libpng */
 564     This->png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 565     if (!This->png_ptr)
 566         return E_FAIL;
 567
 568     This->info_ptr = png_create_info_struct(This->png_ptr);
 569     if (!This->info_ptr)
 570     {
 571         png_destroy_write_struct(&This->png_ptr, NULL);
 572         This->png_ptr = NULL;
 573         return E_FAIL;
 574     }
 575
 576     This->stream = stream;
 577
 578     /* set up setjmp/longjmp error handling */
 579     if (setjmp(png_jmpbuf(This->png_ptr)))
 580     {
 581         png_destroy_write_struct(&This->png_ptr, &This->info_ptr);
 582         This->png_ptr = NULL;
 583         This->stream = NULL;
 584         return E_FAIL;
 585     }
 586
 587     /* set up custom i/o handling */
 588     png_set_write_fn(This->png_ptr, This, user_write_data, user_flush);
 589
 590     return S_OK;
 591 }
 592
 593 static HRESULT CDECL png_encoder_get_supported_format(struct encoder* iface, GUID *pixel_format, DWORD *bpp, BOOL *indexed)
 594 {
 595     int i;
 596
 597     for (i=0; formats[i].guid; i++)
 598     {
 599         if (memcmp(formats[i].guid, pixel_format, sizeof(GUID)) == 0)
 600             break;
 601     }
 602
 603     if (!formats[i].guid)
 604         i = 0;
 605
 606     *pixel_format = *formats[i].guid;
 607     *bpp = formats[i].bpp;
 608     *indexed = (formats[i].color_type == PNG_COLOR_TYPE_PALETTE);
 609
 610     return S_OK;
 611 }
 612
 613 static HRESULT CDECL png_encoder_create_frame(struct encoder *encoder, const struct encoder_frame *encoder_frame)
 614 {
 615     struct png_encoder *This = impl_from_encoder(encoder);
 616     int i;
 617
 618     for (i=0; formats[i].guid; i++)
 619     {
 620         if (memcmp(formats[i].guid, &encoder_frame->pixel_format, sizeof(GUID)) == 0)
 621         {
 622             This->format = &formats[i];
 623             break;
 624         }
 625     }
 626
 627     if (!formats[i].guid)
 628     {
 629         ERR("invalid pixel format %s\n", wine_dbgstr_guid(&encoder_frame->pixel_format));
 630         return E_FAIL;
 631     }
 632
 633     /* set up setjmp/longjmp error handling */
 634     if (setjmp(png_jmpbuf(This->png_ptr)))
 635         return E_FAIL;
 636
 637     This->encoder_frame = *encoder_frame;
 638     This->lines_written = 0;
 639
 640     if (encoder_frame->interlace)
 641     {
 642         /* libpng requires us to write all data multiple times in this case. */
 643         This->stride = (This->format->bpp * encoder_frame->width + 7)/8;
 644         This->data = malloc(encoder_frame->height * This->stride);
 645         if (!This->data)
 646             return E_OUTOFMEMORY;
 647     }
 648
 649     /* Tell PNG we need to byte swap if writing a >8-bpp image */
 650     if (This->format->bit_depth > 8)
 651         png_set_swap(This->png_ptr);
 652
 653     png_set_IHDR(This->png_ptr, This->info_ptr, encoder_frame->width, encoder_frame->height,
 654         This->format->bit_depth, This->format->color_type,
 655         encoder_frame->interlace ? PNG_INTERLACE_ADAM7 : PNG_INTERLACE_NONE,
 656         PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
 657
 658     if (encoder_frame->dpix != 0.0 && encoder_frame->dpiy != 0.0)
 659     {
 660         png_set_pHYs(This->png_ptr, This->info_ptr, (encoder_frame->dpix+0.0127) / 0.0254,
 661             (encoder_frame->dpiy+0.0127) / 0.0254, PNG_RESOLUTION_METER);
 662     }
 663
 664     if (This->format->color_type == PNG_COLOR_TYPE_PALETTE && encoder_frame->num_colors)
 665     {
 666         png_color png_palette[256];
 667         png_byte trans[256];
 668         UINT i, num_trans = 0, colors;
 669
 670         /* Newer libpng versions don't accept larger palettes than the declared
 671          * bit depth, so we need to generate the palette of the correct length.
 672          */
 673         colors = min(encoder_frame->num_colors, 1 << This->format->bit_depth);
 674
 675         for (i = 0; i < colors; i++)
 676         {
 677             png_palette[i].red = (encoder_frame->palette[i] >> 16) & 0xff;
 678             png_palette[i].green = (encoder_frame->palette[i] >> 8) & 0xff;
 679             png_palette[i].blue = encoder_frame->palette[i] & 0xff;
 680             trans[i] = (encoder_frame->palette[i] >> 24) & 0xff;
 681             if (trans[i] != 0xff)
 682                 num_trans = i+1;
 683         }
 684
 685         png_set_PLTE(This->png_ptr, This->info_ptr, png_palette, colors);
 686
 687         if (num_trans)
 688             png_set_tRNS(This->png_ptr, This->info_ptr, trans, num_trans, NULL);
 689     }
 690
 691     png_write_info(This->png_ptr, This->info_ptr);
 692
 693     if (This->format->remove_filler)
 694         png_set_filler(This->png_ptr, 0, PNG_FILLER_AFTER);
 695
 696     if (This->format->swap_rgb)
 697         png_set_bgr(This->png_ptr);
 698
 699     if (encoder_frame->interlace)
 700         This->passes = png_set_interlace_handling(This->png_ptr);
 701
 702     if (encoder_frame->filter != WICPngFilterUnspecified)
 703     {
 704         static const int png_filter_map[] =
 705         {
 706             /* WICPngFilterUnspecified */ PNG_NO_FILTERS,
 707             /* WICPngFilterNone */        PNG_FILTER_NONE,
 708             /* WICPngFilterSub */         PNG_FILTER_SUB,
 709             /* WICPngFilterUp */          PNG_FILTER_UP,
 710             /* WICPngFilterAverage */     PNG_FILTER_AVG,
 711             /* WICPngFilterPaeth */       PNG_FILTER_PAETH,
 712             /* WICPngFilterAdaptive */    PNG_ALL_FILTERS,
 713         };
 714
 715         png_set_filter(This->png_ptr, 0, png_filter_map[encoder_frame->filter]);
 716     }
 717
 718     return S_OK;
 719 }
 720
 721 static HRESULT CDECL png_encoder_write_lines(struct encoder* encoder, BYTE *data, DWORD line_count, DWORD stride)
 722 {
 723     struct png_encoder *This = impl_from_encoder(encoder);
 724     png_byte **row_pointers=NULL;
 725     UINT i;
 726
 727     if (This->encoder_frame.interlace)
 728     {
 729         /* Just store the data so we can write it in multiple passes in Commit. */
 730         for (i=0; i<line_count; i++)
 731             memcpy(This->data + This->stride * (This->lines_written + i),
 732                    data + stride * i,
 733                    This->stride);
 734
 735         This->lines_written += line_count;
 736
 737         return S_OK;
 738     }
 739
 740     /* set up setjmp/longjmp error handling */
 741     if (setjmp(png_jmpbuf(This->png_ptr)))
 742     {
 743         free(row_pointers);
 744         return E_FAIL;
 745     }
 746
 747     row_pointers = malloc(line_count * sizeof(png_byte*));
 748     if (!row_pointers)
 749         return E_OUTOFMEMORY;
 750
 751     for (i=0; i<line_count; i++)
 752         row_pointers[i] = data + stride * i;
 753
 754     png_write_rows(This->png_ptr, row_pointers, line_count);
 755     This->lines_written += line_count;
 756
 757     free(row_pointers);
 758
 759     return S_OK;
 760 }
 761
 762 static HRESULT CDECL png_encoder_commit_frame(struct encoder *encoder)
 763 {
 764     struct png_encoder *This = impl_from_encoder(encoder);
 765     png_byte **row_pointers=NULL;
 766
 767     /* set up setjmp/longjmp error handling */
 768     if (setjmp(png_jmpbuf(This->png_ptr)))
 769     {
 770         free(row_pointers);
 771         return E_FAIL;
 772     }
 773
 774     if (This->encoder_frame.interlace)
 775     {
 776         int i;
 777
 778         row_pointers = malloc(This->encoder_frame.height * sizeof(png_byte*));
 779         if (!row_pointers)
 780             return E_OUTOFMEMORY;
 781
 782         for (i=0; i<This->encoder_frame.height; i++)
 783             row_pointers[i] = This->data + This->stride * i;
 784
 785         for (i=0; i<This->passes; i++)
 786             png_write_rows(This->png_ptr, row_pointers, This->encoder_frame.height);
 787     }
 788
 789     png_write_end(This->png_ptr, This->info_ptr);
 790
 791     free(row_pointers);
 792
 793     return S_OK;
 794 }
 795
 796 static HRESULT CDECL png_encoder_commit_file(struct encoder *encoder)
 797 {
 798     return S_OK;
 799 }
 800
 801 static void CDECL png_encoder_destroy(struct encoder *encoder)
 802 {
 803     struct png_encoder *This = impl_from_encoder(encoder);
 804     if (This->png_ptr)
 805         png_destroy_write_struct(&This->png_ptr, &This->info_ptr);
 806     free(This->data);
 807     RtlFreeHeap(GetProcessHeap(), 0, This);
 808 }
 809
 810 static const struct encoder_funcs png_encoder_vtable = {
 811     png_encoder_initialize,
 812     png_encoder_get_supported_format,
 813     png_encoder_create_frame,
 814     png_encoder_write_lines,
 815     png_encoder_commit_frame,
 816     png_encoder_commit_file,
 817     png_encoder_destroy
 818 };
 819
 820 HRESULT CDECL png_encoder_create(struct encoder_info *info, struct encoder **result)
 821 {
 822     struct png_encoder *This;
 823
 824     This = RtlAllocateHeap(GetProcessHeap(), 0, sizeof(*This));
 825
 826     if (!This)
 827     {
 828         return E_OUTOFMEMORY;
 829     }
 830
 831     This->encoder.vtable = &png_encoder_vtable;
 832     This->png_ptr = NULL;
 833     This->info_ptr = NULL;
 834     This->data = NULL;
 835     *result = &This->encoder;
 836
 837     info->flags = ENCODER_FLAGS_SUPPORTS_METADATA;
 838     info->container_format = GUID_ContainerFormatPng;
 839     info->clsid = CLSID_WICPngEncoder;
 840     info->encoder_options[0] = ENCODER_OPTION_INTERLACE;
 841     info->encoder_options[1] = ENCODER_OPTION_FILTER;
 842     info->encoder_options[2] = ENCODER_OPTION_END;
 843
 844     return S_OK;
 845 }