gtkmm-osx/trunk/libpng-1.2.5/contrib/visupng/VisualPng.c

   1 //------------------------------------
   2 //  VisualPng.C -- Shows a PNG image
   3 //------------------------------------
   4
   5 // Copyright 2000, Willem van Schaik.  For conditions of distribution and
   6 // use, see the copyright/license/disclaimer notice in png.h
   7
   8 // switches
   9
  10 // defines
  11
  12 #define PROGNAME  "VisualPng"
  13 #define LONGNAME  "Win32 Viewer for PNG-files"
  14 #define VERSION   "1.0 of 2000 June 07"
  15
  16 // constants
  17
  18 #define MARGIN 8
  19
  20 // standard includes
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <windows.h>
  26
  27 // application includes
  28
  29 #include "png.h"
  30 #include "pngfile.h"
  31 #include "resource.h"
  32
  33 // macros
  34
  35 // function prototypes
  36
  37 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
  38 BOOL    CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
  39
  40 BOOL CenterAbout (HWND hwndChild, HWND hwndParent);
  41
  42 BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
  43         int *pFileIndex);
  44
  45 BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,
  46         PTSTR pstrPrevName, PTSTR pstrNextName);
  47
  48 BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,
  49         png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,
  50         png_color *pBkgColor);
  51
  52 BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
  53         BYTE **ppDiData, int cxWinSize, int cyWinSize,
  54         BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
  55         BOOL bStretched);
  56
  57 BOOL InitBitmap (
  58         BYTE *pDiData, int cxWinSize, int cyWinSize);
  59
  60 BOOL FillBitmap (
  61         BYTE *pDiData, int cxWinSize, int cyWinSize,
  62         BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
  63         BOOL bStretched);
  64
  65 // a few global variables
  66
  67 static char *szProgName = PROGNAME;
  68 static char *szAppName = LONGNAME;
  69 static char *szIconName = PROGNAME;
  70 static char szCmdFileName [MAX_PATH];
  71
  72 // MAIN routine
  73
  74 int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
  75                     PSTR szCmdLine, int iCmdShow)
  76 {
  77     HACCEL   hAccel;
  78     HWND     hwnd;
  79     MSG      msg;
  80     WNDCLASS wndclass;
  81     int ixBorders, iyBorders;
  82
  83     wndclass.style         = CS_HREDRAW | CS_VREDRAW;
  84     wndclass.lpfnWndProc   = WndProc;
  85     wndclass.cbClsExtra    = 0;
  86     wndclass.cbWndExtra    = 0;
  87     wndclass.hInstance     = hInstance;
  88     wndclass.hIcon         = LoadIcon (hInstance, szIconName) ;
  89     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW);
  90     wndclass.hbrBackground = NULL; // (HBRUSH) GetStockObject (GRAY_BRUSH);
  91     wndclass.lpszMenuName  = szProgName;
  92     wndclass.lpszClassName = szProgName;
  93
  94     if (!RegisterClass (&wndclass))
  95     {
  96         MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),
  97             szProgName, MB_ICONERROR);
  98         return 0;
  99     }
 100
 101     // if filename given on commandline, store it
 102     if ((szCmdLine != NULL) && (*szCmdLine != '\0'))
 103         if (szCmdLine[0] == '"')
 104             strncpy (szCmdFileName, szCmdLine + 1, strlen(szCmdLine) - 2);
 105         else
 106             strcpy (szCmdFileName, szCmdLine);
 107     else
 108         strcpy (szCmdFileName, "");
 109
 110     // calculate size of window-borders
 111     ixBorders = 2 * (GetSystemMetrics (SM_CXBORDER) +
 112                      GetSystemMetrics (SM_CXDLGFRAME));
 113     iyBorders = 2 * (GetSystemMetrics (SM_CYBORDER) +
 114                      GetSystemMetrics (SM_CYDLGFRAME)) +
 115                      GetSystemMetrics (SM_CYCAPTION) +
 116                      GetSystemMetrics (SM_CYMENUSIZE) +
 117                      1; /* WvS: don't ask me why? */
 118
 119     hwnd = CreateWindow (szProgName, szAppName,
 120         WS_OVERLAPPEDWINDOW,
 121         CW_USEDEFAULT, CW_USEDEFAULT,
 122         512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,
 123 //      CW_USEDEFAULT, CW_USEDEFAULT,
 124         NULL, NULL, hInstance, NULL);
 125
 126     ShowWindow (hwnd, iCmdShow);
 127     UpdateWindow (hwnd);
 128
 129     hAccel = LoadAccelerators (hInstance, szProgName);
 130
 131     while (GetMessage (&msg, NULL, 0, 0))
 132     {
 133         if (!TranslateAccelerator (hwnd, hAccel, &msg))
 134         {
 135             TranslateMessage (&msg);
 136             DispatchMessage (&msg);
 137         }
 138     }
 139     return msg.wParam;
 140 }
 141
 142 LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
 143         LPARAM lParam)
 144 {
 145     static HINSTANCE          hInstance ;
 146     static HDC                hdc;
 147     static PAINTSTRUCT        ps;
 148     static HMENU              hMenu;
 149
 150     static BITMAPFILEHEADER  *pbmfh;
 151     static BITMAPINFOHEADER  *pbmih;
 152     static BYTE              *pbImage;
 153     static int                cxWinSize, cyWinSize;
 154     static int                cxImgSize, cyImgSize;
 155     static int                cImgChannels;
 156     static png_color          bkgColor = {127, 127, 127};
 157
 158     static BOOL               bStretched = TRUE;
 159
 160     static BYTE              *pDib = NULL;
 161     static BYTE              *pDiData = NULL;
 162
 163     static TCHAR              szImgPathName [MAX_PATH];
 164     static TCHAR              szTitleName [MAX_PATH];
 165
 166     static TCHAR             *pPngFileList = NULL;
 167     static int                iPngFileCount;
 168     static int                iPngFileIndex;
 169
 170     BOOL                      bOk;
 171
 172     switch (message)
 173     {
 174     case WM_CREATE:
 175         hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
 176         PngFileInitialize (hwnd);
 177
 178         strcpy (szImgPathName, "");
 179
 180         // in case we process file given on command-line
 181
 182         if (szCmdFileName[0] != '\0')
 183         {
 184             strcpy (szImgPathName, szCmdFileName);
 185
 186             // read the other png-files in the directory for later
 187             // next/previous commands
 188
 189             BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
 190                           &iPngFileIndex);
 191
 192             // load the image from file
 193
 194             if (!LoadImageFile (hwnd, szImgPathName,
 195                 &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
 196                 return 0;
 197
 198             // invalidate the client area for later update
 199
 200             InvalidateRect (hwnd, NULL, TRUE);
 201
 202             // display the PNG into the DIBitmap
 203
 204             DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
 205                 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
 206         }
 207
 208         return 0;
 209
 210     case WM_SIZE:
 211         cxWinSize = LOWORD (lParam);
 212         cyWinSize = HIWORD (lParam);
 213
 214         // invalidate the client area for later update
 215
 216         InvalidateRect (hwnd, NULL, TRUE);
 217
 218         // display the PNG into the DIBitmap
 219
 220         DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
 221             pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
 222
 223         return 0;
 224
 225     case WM_INITMENUPOPUP:
 226         hMenu = GetMenu (hwnd);
 227
 228         if (pbImage)
 229             EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);
 230         else
 231             EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);
 232
 233         return 0;
 234
 235     case WM_COMMAND:
 236         hMenu = GetMenu (hwnd);
 237
 238         switch (LOWORD (wParam))
 239         {
 240         case IDM_FILE_OPEN:
 241
 242             // show the File Open dialog box
 243
 244             if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))
 245                 return 0;
 246
 247             // read the other png-files in the directory for later
 248             // next/previous commands
 249
 250             BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
 251                           &iPngFileIndex);
 252
 253             // load the image from file
 254
 255             if (!LoadImageFile (hwnd, szImgPathName,
 256                 &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
 257                 return 0;
 258
 259             // invalidate the client area for later update
 260
 261             InvalidateRect (hwnd, NULL, TRUE);
 262
 263             // display the PNG into the DIBitmap
 264
 265             DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
 266                 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
 267
 268             return 0;
 269
 270         case IDM_FILE_SAVE:
 271
 272             // show the File Save dialog box
 273
 274             if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))
 275                 return 0;
 276
 277             // save the PNG to a disk file
 278
 279             SetCursor (LoadCursor (NULL, IDC_WAIT));
 280             ShowCursor (TRUE);
 281
 282             bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,
 283                   bkgColor);
 284
 285             ShowCursor (FALSE);
 286             SetCursor (LoadCursor (NULL, IDC_ARROW));
 287
 288             if (!bOk)
 289                 MessageBox (hwnd, TEXT ("Error in saving the PNG image"),
 290                 szProgName, MB_ICONEXCLAMATION | MB_OK);
 291             return 0;
 292
 293         case IDM_FILE_NEXT:
 294
 295             // read next entry in the directory
 296
 297             if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
 298                 NULL, szImgPathName))
 299             {
 300                 if (strcmp (szImgPathName, "") == 0)
 301                     return 0;
 302
 303                 // load the image from file
 304
 305                 if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
 306                         &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
 307                     return 0;
 308
 309                 // invalidate the client area for later update
 310
 311                 InvalidateRect (hwnd, NULL, TRUE);
 312
 313                 // display the PNG into the DIBitmap
 314
 315                 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
 316                     pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
 317             }
 318
 319             return 0;
 320
 321         case IDM_FILE_PREVIOUS:
 322
 323             // read previous entry in the directory
 324
 325             if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
 326                 szImgPathName, NULL))
 327             {
 328
 329                 if (strcmp (szImgPathName, "") == 0)
 330                     return 0;
 331
 332                 // load the image from file
 333
 334                 if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
 335                     &cyImgSize, &cImgChannels, &bkgColor))
 336                     return 0;
 337
 338                 // invalidate the client area for later update
 339
 340                 InvalidateRect (hwnd, NULL, TRUE);
 341
 342                 // display the PNG into the DIBitmap
 343
 344                 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
 345                     pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
 346             }
 347
 348             return 0;
 349
 350         case IDM_FILE_EXIT:
 351
 352             // more cleanup needed...
 353
 354             // free image buffer
 355
 356             if (pDib != NULL)
 357             {
 358                 free (pDib);
 359                 pDib = NULL;
 360             }
 361
 362             // free file-list
 363
 364             if (pPngFileList != NULL)
 365             {
 366                 free (pPngFileList);
 367                 pPngFileList = NULL;
 368             }
 369
 370             // let's go ...
 371
 372             exit (0);
 373
 374             return 0;
 375
 376         case IDM_OPTIONS_STRETCH:
 377             bStretched = !bStretched;
 378             if (bStretched)
 379                 CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);
 380             else
 381                 CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);
 382
 383             // invalidate the client area for later update
 384
 385             InvalidateRect (hwnd, NULL, TRUE);
 386
 387             // display the PNG into the DIBitmap
 388
 389             DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
 390                 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
 391
 392             return 0;
 393
 394         case IDM_HELP_ABOUT:
 395             DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;
 396             return 0;
 397
 398         } // end switch
 399
 400         break;
 401
 402     case WM_PAINT:
 403         hdc = BeginPaint (hwnd, &ps);
 404
 405         if (pDib)
 406             SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,
 407                 0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);
 408
 409         EndPaint (hwnd, &ps);
 410         return 0;
 411
 412     case WM_DESTROY:
 413         if (pbmfh)
 414         {
 415             free (pbmfh);
 416             pbmfh = NULL;
 417         }
 418
 419         PostQuitMessage (0);
 420         return 0;
 421     }
 422
 423     return DefWindowProc (hwnd, message, wParam, lParam);
 424 }
 425
 426 BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,
 427                             WPARAM wParam, LPARAM lParam)
 428 {
 429      switch (message)
 430      {
 431      case WM_INITDIALOG :
 432           ShowWindow (hDlg, SW_HIDE);
 433           CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));
 434           ShowWindow (hDlg, SW_SHOW);
 435           return TRUE ;
 436
 437      case WM_COMMAND :
 438           switch (LOWORD (wParam))
 439           {
 440           case IDOK :
 441           case IDCANCEL :
 442                EndDialog (hDlg, 0) ;
 443                return TRUE ;
 444           }
 445           break ;
 446      }
 447      return FALSE ;
 448 }
 449
 450 //---------------
 451 //  CenterAbout
 452 //---------------
 453
 454 BOOL CenterAbout (HWND hwndChild, HWND hwndParent)
 455 {
 456    RECT    rChild, rParent, rWorkArea;
 457    int     wChild, hChild, wParent, hParent;
 458    int     xNew, yNew;
 459    BOOL  bResult;
 460
 461    // Get the Height and Width of the child window
 462    GetWindowRect (hwndChild, &rChild);
 463    wChild = rChild.right - rChild.left;
 464    hChild = rChild.bottom - rChild.top;
 465
 466    // Get the Height and Width of the parent window
 467    GetWindowRect (hwndParent, &rParent);
 468    wParent = rParent.right - rParent.left;
 469    hParent = rParent.bottom - rParent.top;
 470
 471    // Get the limits of the 'workarea'
 472    bResult = SystemParametersInfo(
 473       SPI_GETWORKAREA,  // system parameter to query or set
 474       sizeof(RECT),
 475       &rWorkArea,
 476       0);
 477    if (!bResult) {
 478       rWorkArea.left = rWorkArea.top = 0;
 479       rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);
 480       rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);
 481    }
 482
 483    // Calculate new X position, then adjust for workarea
 484    xNew = rParent.left + ((wParent - wChild) /2);
 485    if (xNew < rWorkArea.left) {
 486       xNew = rWorkArea.left;
 487    } else if ((xNew+wChild) > rWorkArea.right) {
 488       xNew = rWorkArea.right - wChild;
 489    }
 490
 491    // Calculate new Y position, then adjust for workarea
 492    yNew = rParent.top  + ((hParent - hChild) /2);
 493    if (yNew < rWorkArea.top) {
 494       yNew = rWorkArea.top;
 495    } else if ((yNew+hChild) > rWorkArea.bottom) {
 496       yNew = rWorkArea.bottom - hChild;
 497    }
 498
 499    // Set it, and return
 500    return SetWindowPos (hwndChild, NULL, xNew, yNew, 0, 0, SWP_NOSIZE |
 501           SWP_NOZORDER);
 502 }
 503
 504 //----------------
 505 //  BuildPngList
 506 //----------------
 507
 508 BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
 509      int *pFileIndex)
 510 {
 511     static TCHAR              szImgPathName [MAX_PATH];
 512     static TCHAR              szImgFileName [MAX_PATH];
 513     static TCHAR              szImgFindName [MAX_PATH];
 514
 515     WIN32_FIND_DATA           finddata;
 516     HANDLE                    hFind;
 517
 518     static TCHAR              szTmp [MAX_PATH];
 519     BOOL                      bOk;
 520     int                       i, ii;
 521     int                       j, jj;
 522
 523     // free previous file-list
 524
 525     if (*ppFileList != NULL)
 526     {
 527         free (*ppFileList);
 528         *ppFileList = NULL;
 529     }
 530
 531     // extract foldername, filename and search-name
 532
 533     strcpy (szImgPathName, pstrPathName);
 534     strcpy (szImgFileName, strrchr (pstrPathName, '\\') + 1);
 535
 536     strcpy (szImgFindName, szImgPathName);
 537     *(strrchr (szImgFindName, '\\') + 1) = '\0';
 538     strcat (szImgFindName, "*.png");
 539
 540     // first cycle: count number of files in directory for memory allocation
 541
 542     *pFileCount = 0;
 543
 544     hFind = FindFirstFile(szImgFindName, &finddata);
 545     bOk = (hFind != (HANDLE) -1);
 546
 547     while (bOk)
 548     {
 549         *pFileCount += 1;
 550         bOk = FindNextFile(hFind, &finddata);
 551     }
 552     FindClose(hFind);
 553
 554     // allocation memory for file-list
 555
 556     *ppFileList = (TCHAR *) malloc (*pFileCount * MAX_PATH);
 557
 558     // second cycle: read directory and store filenames in file-list
 559
 560     hFind = FindFirstFile(szImgFindName, &finddata);
 561     bOk = (hFind != (HANDLE) -1);
 562
 563     i = 0;
 564     ii = 0;
 565     while (bOk)
 566     {
 567         strcpy (*ppFileList + ii, szImgPathName);
 568         strcpy (strrchr(*ppFileList + ii, '\\') + 1, finddata.cFileName);
 569
 570         if (strcmp(pstrPathName, *ppFileList + ii) == 0)
 571             *pFileIndex = i;
 572
 573         ii += MAX_PATH;
 574         i++;
 575
 576         bOk = FindNextFile(hFind, &finddata);
 577     }
 578     FindClose(hFind);
 579
 580     // finally we must sort the file-list
 581
 582     for (i = 0; i < *pFileCount - 1; i++)
 583     {
 584         ii = i * MAX_PATH;
 585         for (j = i+1; j < *pFileCount; j++)
 586         {
 587             jj = j * MAX_PATH;
 588             if (strcmp (*ppFileList + ii, *ppFileList + jj) > 0)
 589             {
 590                 strcpy (szTmp, *ppFileList + jj);
 591                 strcpy (*ppFileList + jj, *ppFileList + ii);
 592                 strcpy (*ppFileList + ii, szTmp);
 593
 594                 // check if this was the current image that we moved
 595
 596                 if (*pFileIndex == i)
 597                     *pFileIndex = j;
 598                 else
 599                     if (*pFileIndex == j)
 600                         *pFileIndex = i;
 601             }
 602         }
 603     }
 604
 605     return TRUE;
 606 }
 607
 608 //----------------
 609 //  SearchPngList
 610 //----------------
 611
 612 BOOL SearchPngList (
 613         TCHAR *pFileList, int FileCount, int *pFileIndex,
 614         PTSTR pstrPrevName, PTSTR pstrNextName)
 615 {
 616     if (FileCount > 0)
 617     {
 618         // get previous entry
 619
 620         if (pstrPrevName != NULL)
 621         {
 622             if (*pFileIndex > 0)
 623                 *pFileIndex -= 1;
 624             else
 625                 *pFileIndex = FileCount - 1;
 626
 627             strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
 628         }
 629
 630         // get next entry
 631
 632         if (pstrNextName != NULL)
 633         {
 634             if (*pFileIndex < FileCount - 1)
 635                 *pFileIndex += 1;
 636             else
 637                 *pFileIndex = 0;
 638
 639             strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
 640         }
 641
 642         return TRUE;
 643     }
 644     else
 645     {
 646         return FALSE;
 647     }
 648 }
 649
 650 //-----------------
 651 //  LoadImageFile
 652 //-----------------
 653
 654 BOOL LoadImageFile (HWND hwnd, PTSTR pstrPathName,
 655                 png_byte **ppbImage, int *pxImgSize, int *pyImgSize,
 656                 int *piChannels, png_color *pBkgColor)
 657 {
 658     static TCHAR szTmp [MAX_PATH];
 659
 660     // if there's an existing PNG, free the memory
 661
 662     if (*ppbImage)
 663     {
 664         free (*ppbImage);
 665         *ppbImage = NULL;
 666     }
 667
 668     // Load the entire PNG into memory
 669
 670     SetCursor (LoadCursor (NULL, IDC_WAIT));
 671     ShowCursor (TRUE);
 672
 673     PngLoadImage (pstrPathName, ppbImage, pxImgSize, pyImgSize, piChannels,
 674                   pBkgColor);
 675
 676     ShowCursor (FALSE);
 677     SetCursor (LoadCursor (NULL, IDC_ARROW));
 678
 679     if (*ppbImage != NULL)
 680     {
 681         sprintf (szTmp, "VisualPng - %s", strrchr(pstrPathName, '\\') + 1);
 682         SetWindowText (hwnd, szTmp);
 683     }
 684     else
 685     {
 686         MessageBox (hwnd, TEXT ("Error in loading the PNG image"),
 687             szProgName, MB_ICONEXCLAMATION | MB_OK);
 688         return FALSE;
 689     }
 690
 691     return TRUE;
 692 }
 693
 694 //----------------
 695 //  DisplayImage
 696 //----------------
 697
 698 BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
 699         BYTE **ppDiData, int cxWinSize, int cyWinSize,
 700         BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
 701         BOOL bStretched)
 702 {
 703     BYTE                       *pDib = *ppDib;
 704     BYTE                       *pDiData = *ppDiData;
 705     // BITMAPFILEHEADER        *pbmfh;
 706     BITMAPINFOHEADER           *pbmih;
 707     WORD                        wDIRowBytes;
 708     png_color                   bkgBlack = {0, 0, 0};
 709     png_color                   bkgGray  = {127, 127, 127};
 710     png_color                   bkgWhite = {255, 255, 255};
 711
 712     // allocate memory for the Device Independant bitmap
 713
 714     wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;
 715
 716     if (pDib)
 717     {
 718         free (pDib);
 719         pDib = NULL;
 720     }
 721
 722     if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
 723         wDIRowBytes * cyWinSize)))
 724     {
 725         MessageBox (hwnd, TEXT ("Error in displaying the PNG image"),
 726             szProgName, MB_ICONEXCLAMATION | MB_OK);
 727         *ppDib = pDib = NULL;
 728         return FALSE;
 729     }
 730     *ppDib = pDib;
 731     memset (pDib, 0, sizeof(BITMAPINFOHEADER));
 732
 733     // initialize the dib-structure
 734
 735     pbmih = (BITMAPINFOHEADER *) pDib;
 736     pbmih->biSize = sizeof(BITMAPINFOHEADER);
 737     pbmih->biWidth = cxWinSize;
 738     pbmih->biHeight = -((long) cyWinSize);
 739     pbmih->biPlanes = 1;
 740     pbmih->biBitCount = 24;
 741     pbmih->biCompression = 0;
 742     pDiData = pDib + sizeof(BITMAPINFOHEADER);
 743     *ppDiData = pDiData;
 744
 745     // first fill bitmap with gray and image border
 746
 747     InitBitmap (pDiData, cxWinSize, cyWinSize);
 748
 749     // then fill bitmap with image
 750
 751     if (pbImage)
 752     {
 753         FillBitmap (
 754             pDiData, cxWinSize, cyWinSize,
 755             pbImage, cxImgSize, cyImgSize, cImgChannels,
 756             bStretched);
 757     }
 758
 759     return TRUE;
 760 }
 761
 762 //--------------
 763 //  InitBitmap
 764 //--------------
 765
 766 BOOL InitBitmap (BYTE *pDiData, int cxWinSize, int cyWinSize)
 767 {
 768     BYTE *dst;
 769     int x, y, col;
 770
 771     // initialize the background with gray
 772
 773     dst = pDiData;
 774     for (y = 0; y < cyWinSize; y++)
 775     {
 776         col = 0;
 777         for (x = 0; x < cxWinSize; x++)
 778         {
 779             // fill with GRAY
 780             *dst++ = 127;
 781             *dst++ = 127;
 782             *dst++ = 127;
 783             col += 3;
 784         }
 785         // rows start on 4 byte boundaries
 786         while ((col % 4) != 0)
 787         {
 788             dst++;
 789             col++;
 790         }
 791     }
 792
 793     return TRUE;
 794 }
 795
 796 //--------------
 797 //  FillBitmap
 798 //--------------
 799
 800 BOOL FillBitmap (
 801         BYTE *pDiData, int cxWinSize, int cyWinSize,
 802         BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
 803         BOOL bStretched)
 804 {
 805     BYTE *pStretchedImage;
 806     BYTE *pImg;
 807     BYTE *src, *dst;
 808     BYTE r, g, b, a;
 809     const int cDIChannels = 3;
 810     WORD wImgRowBytes;
 811     WORD wDIRowBytes;
 812     int cxNewSize, cyNewSize;
 813     int cxImgPos, cyImgPos;
 814     int xImg, yImg;
 815     int xWin, yWin;
 816     int xOld, yOld;
 817     int xNew, yNew;
 818
 819     if (bStretched)
 820     {
 821         cxNewSize = cxWinSize - 2 * MARGIN;
 822         cyNewSize = cyWinSize - 2 * MARGIN;
 823
 824         // stretch the image to it's window determined size
 825
 826         // the following two are the same, but the first has side-effects
 827         // because of rounding
 828 //      if ((cyNewSize / cxNewSize) > (cyImgSize / cxImgSize))
 829         if ((cyNewSize * cxImgSize) > (cyImgSize * cxNewSize))
 830         {
 831             cyNewSize = cxNewSize * cyImgSize / cxImgSize;
 832             cxImgPos = MARGIN;
 833             cyImgPos = (cyWinSize - cyNewSize) / 2;
 834         }
 835         else
 836         {
 837             cxNewSize = cyNewSize * cxImgSize / cyImgSize;
 838             cyImgPos = MARGIN;
 839             cxImgPos = (cxWinSize - cxNewSize) / 2;
 840         }
 841
 842         pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
 843         pImg = pStretchedImage;
 844
 845         for (yNew = 0; yNew < cyNewSize; yNew++)
 846         {
 847             yOld = yNew * cyImgSize / cyNewSize;
 848             for (xNew = 0; xNew < cxNewSize; xNew++)
 849             {
 850                 xOld = xNew * cxImgSize / cxNewSize;
 851
 852                 r = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 0);
 853                 g = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 1);
 854                 b = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 2);
 855                 *pImg++ = r;
 856                 *pImg++ = g;
 857                 *pImg++ = b;
 858                 if (cImgChannels == 4)
 859                 {
 860                     a = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld)
 861                         + 3);
 862                     *pImg++ = a;
 863                 }
 864             }
 865         }
 866
 867         // calculate row-bytes
 868
 869         wImgRowBytes = cImgChannels * cxNewSize;
 870         wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
 871
 872         // copy image to screen
 873
 874         for (yImg = 0, yWin = cyImgPos; yImg < cyNewSize; yImg++, yWin++)
 875         {
 876             if (yWin >= cyWinSize - cyImgPos)
 877                 break;
 878             src = pStretchedImage + yImg * wImgRowBytes;
 879             dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
 880
 881             for (xImg = 0, xWin = cxImgPos; xImg < cxNewSize; xImg++, xWin++)
 882             {
 883                 if (xWin >= cxWinSize - cxImgPos)
 884                     break;
 885                 r = *src++;
 886                 g = *src++;
 887                 b = *src++;
 888                 *dst++ = b; /* note the reverse order */
 889                 *dst++ = g;
 890                 *dst++ = r;
 891                 if (cImgChannels == 4)
 892                 {
 893                     a = *src++;
 894                 }
 895             }
 896         }
 897
 898         // free memory
 899
 900         if (pStretchedImage != NULL)
 901         {
 902             free (pStretchedImage);
 903             pStretchedImage = NULL;
 904         }
 905
 906     }
 907
 908     // process the image not-stretched
 909
 910     else
 911     {
 912         // calculate the central position
 913
 914         cxImgPos = (cxWinSize - cxImgSize) / 2;
 915         cyImgPos = (cyWinSize - cyImgSize) / 2;
 916
 917         // check for image larger than window
 918
 919         if (cxImgPos < MARGIN)
 920             cxImgPos = MARGIN;
 921         if (cyImgPos < MARGIN)
 922             cyImgPos = MARGIN;
 923
 924         // calculate both row-bytes
 925
 926         wImgRowBytes = cImgChannels * cxImgSize;
 927         wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
 928
 929         // copy image to screen
 930
 931         for (yImg = 0, yWin = cyImgPos; yImg < cyImgSize; yImg++, yWin++)
 932         {
 933             if (yWin >= cyWinSize - MARGIN)
 934                 break;
 935             src = pbImage + yImg * wImgRowBytes;
 936             dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
 937
 938             for (xImg = 0, xWin = cxImgPos; xImg < cxImgSize; xImg++, xWin++)
 939             {
 940                 if (xWin >= cxWinSize - MARGIN)
 941                     break;
 942                 r = *src++;
 943                 g = *src++;
 944                 b = *src++;
 945                 *dst++ = b; /* note the reverse order */
 946                 *dst++ = g;
 947                 *dst++ = r;
 948                 if (cImgChannels == 4)
 949                 {
 950                     a = *src++;
 951                 }
 952             }
 953         }
 954     }
 955
 956     return TRUE;
 957 }
 958
 959 //-----------------
 960 //  end of source
 961 //-----------------