1 /*------------------------------------
2 * VisualPng.C -- Shows a PNG image
3 *------------------------------------
4 *
5 * Copyright 2000,2017 Willem van Schaik.
6 *
7 * This code is released under the libpng license.
8 * For conditions of distribution and use, see the disclaimer
9 * and license in png.h
10 */
11
12 /* switches */
13
14 /* defines */
15
16 #define PROGNAME "VisualPng"
17 #define LONGNAME "Win32 Viewer for PNG-files"
18 #define VERSION "1.0 of 2000 June 07"
19
20 /* constants */
21
22 #define MARGIN 8
23
24 /* standard includes */
25
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <windows.h>
30 #include <zlib.h>
31
32 /* application includes */
33
34 #include "png.h"
35 #include "pngfile.h"
36 #include "resource.h"
37
38 /* macros */
39
40 /* function prototypes */
41
42 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
43 BOOL CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
44
45 BOOL CenterAbout (HWND hwndChild, HWND hwndParent);
46
47 BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
48 int *pFileIndex);
49
50 BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,
51 PTSTR pstrPrevName, PTSTR pstrNextName);
52
53 BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,
54 png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,
55 png_color *pBkgColor);
56
57 BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
58 BYTE **ppDiData, int cxWinSize, int cyWinSize,
59 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
60 BOOL bStretched);
61
62 BOOL InitBitmap (
63 BYTE *pDiData, int cxWinSize, int cyWinSize);
64
65 BOOL FillBitmap (
66 BYTE *pDiData, int cxWinSize, int cyWinSize,
67 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
68 BOOL bStretched);
69
70 /* a few global variables */
71
72 static char *szProgName = PROGNAME;
73 static char *szAppName = LONGNAME;
74 static char *szIconName = PROGNAME;
75 static char szCmdFileName [MAX_PATH];
76
77 /* MAIN routine */
78
WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,PSTR szCmdLine,int iCmdShow)79 int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
80 PSTR szCmdLine, int iCmdShow)
81 {
82 HACCEL hAccel;
83 HWND hwnd;
84 MSG msg;
85 WNDCLASS wndclass;
86 int ixBorders, iyBorders;
87
88 wndclass.style = CS_HREDRAW | CS_VREDRAW;
89 wndclass.lpfnWndProc = WndProc;
90 wndclass.cbClsExtra = 0;
91 wndclass.cbWndExtra = 0;
92 wndclass.hInstance = hInstance;
93 wndclass.hIcon = LoadIcon (hInstance, szIconName) ;
94 wndclass.hCursor = LoadCursor (NULL, IDC_ARROW);
95 wndclass.hbrBackground = NULL; /* (HBRUSH) GetStockObject (GRAY_BRUSH); */
96 wndclass.lpszMenuName = szProgName;
97 wndclass.lpszClassName = szProgName;
98
99 if (!RegisterClass (&wndclass))
100 {
101 MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),
102 szProgName, MB_ICONERROR);
103 return 0;
104 }
105
106 /* if filename given on commandline, store it */
107 if ((szCmdLine != NULL) && (*szCmdLine != '\0'))
108 if (szCmdLine[0] == '"')
109 strncpy (szCmdFileName, szCmdLine + 1, strlen(szCmdLine) - 2);
110 else
111 strcpy (szCmdFileName, szCmdLine);
112 else
113 strcpy (szCmdFileName, "");
114
115 /* calculate size of window-borders */
116 ixBorders = 2 * (GetSystemMetrics (SM_CXBORDER) +
117 GetSystemMetrics (SM_CXDLGFRAME));
118 iyBorders = 2 * (GetSystemMetrics (SM_CYBORDER) +
119 GetSystemMetrics (SM_CYDLGFRAME)) +
120 GetSystemMetrics (SM_CYCAPTION) +
121 GetSystemMetrics (SM_CYMENUSIZE) +
122 1; /* WvS: don't ask me why? */
123
124 hwnd = CreateWindow (szProgName, szAppName,
125 WS_OVERLAPPEDWINDOW,
126 CW_USEDEFAULT, CW_USEDEFAULT,
127 512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,
128 /* CW_USEDEFAULT, CW_USEDEFAULT, */
129 NULL, NULL, hInstance, NULL);
130
131 ShowWindow (hwnd, iCmdShow);
132 UpdateWindow (hwnd);
133
134 hAccel = LoadAccelerators (hInstance, szProgName);
135
136 while (GetMessage (&msg, NULL, 0, 0))
137 {
138 if (!TranslateAccelerator (hwnd, hAccel, &msg))
139 {
140 TranslateMessage (&msg);
141 DispatchMessage (&msg);
142 }
143 }
144 return msg.wParam;
145 }
146
WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)147 LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
148 LPARAM lParam)
149 {
150 static HINSTANCE hInstance ;
151 static HDC hdc;
152 static PAINTSTRUCT ps;
153 static HMENU hMenu;
154
155 static BITMAPFILEHEADER *pbmfh;
156 static BITMAPINFOHEADER *pbmih;
157 static BYTE *pbImage;
158 static int cxWinSize, cyWinSize;
159 static int cxImgSize, cyImgSize;
160 static int cImgChannels;
161 static png_color bkgColor = {127, 127, 127};
162
163 static BOOL bStretched = TRUE;
164
165 static BYTE *pDib = NULL;
166 static BYTE *pDiData = NULL;
167
168 static TCHAR szImgPathName [MAX_PATH];
169 static TCHAR szTitleName [MAX_PATH];
170
171 static TCHAR *pPngFileList = NULL;
172 static int iPngFileCount;
173 static int iPngFileIndex;
174
175 BOOL bOk;
176
177 switch (message)
178 {
179 case WM_CREATE:
180 hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
181 PngFileInitialize (hwnd);
182
183 strcpy (szImgPathName, "");
184
185 /* in case we process file given on command-line */
186
187 if (szCmdFileName[0] != '\0')
188 {
189 strcpy (szImgPathName, szCmdFileName);
190
191 /* read the other png-files in the directory for later */
192 /* next/previous commands */
193
194 BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
195 &iPngFileIndex);
196
197 /* load the image from file */
198
199 if (!LoadImageFile (hwnd, szImgPathName,
200 &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
201 return 0;
202
203 /* invalidate the client area for later update */
204
205 InvalidateRect (hwnd, NULL, TRUE);
206
207 /* display the PNG into the DIBitmap */
208
209 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
210 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
211 }
212
213 return 0;
214
215 case WM_SIZE:
216 cxWinSize = LOWORD (lParam);
217 cyWinSize = HIWORD (lParam);
218
219 /* invalidate the client area for later update */
220
221 InvalidateRect (hwnd, NULL, TRUE);
222
223 /* display the PNG into the DIBitmap */
224
225 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
226 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
227
228 return 0;
229
230 case WM_INITMENUPOPUP:
231 hMenu = GetMenu (hwnd);
232
233 if (pbImage)
234 EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);
235 else
236 EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);
237
238 return 0;
239
240 case WM_COMMAND:
241 hMenu = GetMenu (hwnd);
242
243 switch (LOWORD (wParam))
244 {
245 case IDM_FILE_OPEN:
246
247 /* show the File Open dialog box */
248
249 if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))
250 return 0;
251
252 /* read the other png-files in the directory for later */
253 /* next/previous commands */
254
255 BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
256 &iPngFileIndex);
257
258 /* load the image from file */
259
260 if (!LoadImageFile (hwnd, szImgPathName,
261 &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
262 return 0;
263
264 /* invalidate the client area for later update */
265
266 InvalidateRect (hwnd, NULL, TRUE);
267
268 /* display the PNG into the DIBitmap */
269
270 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
271 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
272
273 return 0;
274
275 case IDM_FILE_SAVE:
276
277 /* show the File Save dialog box */
278
279 if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))
280 return 0;
281
282 /* save the PNG to a disk file */
283
284 SetCursor (LoadCursor (NULL, IDC_WAIT));
285 ShowCursor (TRUE);
286
287 bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,
288 bkgColor);
289
290 ShowCursor (FALSE);
291 SetCursor (LoadCursor (NULL, IDC_ARROW));
292
293 if (!bOk)
294 MessageBox (hwnd, TEXT ("Error in saving the PNG image"),
295 szProgName, MB_ICONEXCLAMATION | MB_OK);
296 return 0;
297
298 case IDM_FILE_NEXT:
299
300 /* read next entry in the directory */
301
302 if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
303 NULL, szImgPathName))
304 {
305 if (strcmp (szImgPathName, "") == 0)
306 return 0;
307
308 /* load the image from file */
309
310 if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
311 &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
312 return 0;
313
314 /* invalidate the client area for later update */
315
316 InvalidateRect (hwnd, NULL, TRUE);
317
318 /* display the PNG into the DIBitmap */
319
320 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
321 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
322 }
323
324 return 0;
325
326 case IDM_FILE_PREVIOUS:
327
328 /* read previous entry in the directory */
329
330 if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
331 szImgPathName, NULL))
332 {
333
334 if (strcmp (szImgPathName, "") == 0)
335 return 0;
336
337 /* load the image from file */
338
339 if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
340 &cyImgSize, &cImgChannels, &bkgColor))
341 return 0;
342
343 /* invalidate the client area for later update */
344
345 InvalidateRect (hwnd, NULL, TRUE);
346
347 /* display the PNG into the DIBitmap */
348
349 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
350 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
351 }
352
353 return 0;
354
355 case IDM_FILE_EXIT:
356
357 /* more cleanup needed... */
358
359 /* free image buffer */
360
361 if (pDib != NULL)
362 {
363 free (pDib);
364 pDib = NULL;
365 }
366
367 /* free file-list */
368
369 if (pPngFileList != NULL)
370 {
371 free (pPngFileList);
372 pPngFileList = NULL;
373 }
374
375 /* let's go ... */
376
377 exit (0);
378
379 return 0;
380
381 case IDM_OPTIONS_STRETCH:
382 bStretched = !bStretched;
383 if (bStretched)
384 CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);
385 else
386 CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);
387
388 /* invalidate the client area for later update */
389
390 InvalidateRect (hwnd, NULL, TRUE);
391
392 /* display the PNG into the DIBitmap */
393
394 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
395 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
396
397 return 0;
398
399 case IDM_HELP_ABOUT:
400 DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;
401 return 0;
402
403 } /* end switch */
404
405 break;
406
407 case WM_PAINT:
408 hdc = BeginPaint (hwnd, &ps);
409
410 if (pDib)
411 SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,
412 0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);
413
414 EndPaint (hwnd, &ps);
415 return 0;
416
417 case WM_DESTROY:
418 if (pbmfh)
419 {
420 free (pbmfh);
421 pbmfh = NULL;
422 }
423
424 PostQuitMessage (0);
425 return 0;
426 }
427
428 return DefWindowProc (hwnd, message, wParam, lParam);
429 }
430
AboutDlgProc(HWND hDlg,UINT message,WPARAM wParam,LPARAM lParam)431 BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,
432 WPARAM wParam, LPARAM lParam)
433 {
434 switch (message)
435 {
436 case WM_INITDIALOG :
437 ShowWindow (hDlg, SW_HIDE);
438 CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));
439 ShowWindow (hDlg, SW_SHOW);
440 return TRUE ;
441
442 case WM_COMMAND :
443 switch (LOWORD (wParam))
444 {
445 case IDOK :
446 case IDCANCEL :
447 EndDialog (hDlg, 0) ;
448 return TRUE ;
449 }
450 break ;
451 }
452 return FALSE ;
453 }
454
455 /*---------------
456 * CenterAbout
457 *---------------
458 */
CenterAbout(HWND hwndChild,HWND hwndParent)459 BOOL CenterAbout (HWND hwndChild, HWND hwndParent)
460 {
461 RECT rChild, rParent, rWorkArea;
462 int wChild, hChild, wParent, hParent;
463 int xNew, yNew;
464 BOOL bResult;
465
466 /* Get the Height and Width of the child window */
467 GetWindowRect (hwndChild, &rChild);
468 wChild = rChild.right - rChild.left;
469 hChild = rChild.bottom - rChild.top;
470
471 /* Get the Height and Width of the parent window */
472 GetWindowRect (hwndParent, &rParent);
473 wParent = rParent.right - rParent.left;
474 hParent = rParent.bottom - rParent.top;
475
476 /* Get the limits of the 'workarea' */
477 bResult = SystemParametersInfo(
478 SPI_GETWORKAREA, /* system parameter to query or set */
479 sizeof(RECT),
480 &rWorkArea,
481 0);
482 if (!bResult) {
483 rWorkArea.left = rWorkArea.top = 0;
484 rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);
485 rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);
486 }
487
488 /* Calculate new X position, then adjust for workarea */
489 xNew = rParent.left + ((wParent - wChild) /2);
490 if (xNew < rWorkArea.left) {
491 xNew = rWorkArea.left;
492 } else if ((xNew+wChild) > rWorkArea.right) {
493 xNew = rWorkArea.right - wChild;
494 }
495
496 /* Calculate new Y position, then adjust for workarea */
497 yNew = rParent.top + ((hParent - hChild) /2);
498 if (yNew < rWorkArea.top) {
499 yNew = rWorkArea.top;
500 } else if ((yNew+hChild) > rWorkArea.bottom) {
501 yNew = rWorkArea.bottom - hChild;
502 }
503
504 /* Set it, and return */
505 return SetWindowPos (hwndChild, NULL, xNew, yNew, 0, 0, SWP_NOSIZE |
506 SWP_NOZORDER);
507 }
508
509 /*----------------
510 * BuildPngList
511 *----------------
512 */
BuildPngList(PTSTR pstrPathName,TCHAR ** ppFileList,int * pFileCount,int * pFileIndex)513 BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
514 int *pFileIndex)
515 {
516 static TCHAR szImgPathName [MAX_PATH];
517 static TCHAR szImgFileName [MAX_PATH];
518 static TCHAR szImgFindName [MAX_PATH];
519
520 WIN32_FIND_DATA finddata;
521 HANDLE hFind;
522
523 static TCHAR szTmp [MAX_PATH];
524 BOOL bOk;
525 int i, ii;
526 int j, jj;
527
528 /* free previous file-list */
529
530 if (*ppFileList != NULL)
531 {
532 free (*ppFileList);
533 *ppFileList = NULL;
534 }
535
536 /* extract foldername, filename and search-name */
537
538 strcpy (szImgPathName, pstrPathName);
539 strcpy (szImgFileName, strrchr (pstrPathName, '\\') + 1);
540
541 strcpy (szImgFindName, szImgPathName);
542 *(strrchr (szImgFindName, '\\') + 1) = '\0';
543 strcat (szImgFindName, "*.png");
544
545 /* first cycle: count number of files in directory for memory allocation */
546
547 *pFileCount = 0;
548
549 hFind = FindFirstFile(szImgFindName, &finddata);
550 bOk = (hFind != (HANDLE) -1);
551
552 while (bOk)
553 {
554 *pFileCount += 1;
555 bOk = FindNextFile(hFind, &finddata);
556 }
557 FindClose(hFind);
558
559 /* allocation memory for file-list */
560
561 *ppFileList = (TCHAR *) malloc (*pFileCount * MAX_PATH);
562
563 /* second cycle: read directory and store filenames in file-list */
564
565 hFind = FindFirstFile(szImgFindName, &finddata);
566 bOk = (hFind != (HANDLE) -1);
567
568 i = 0;
569 ii = 0;
570 while (bOk)
571 {
572 strcpy (*ppFileList + ii, szImgPathName);
573 strcpy (strrchr(*ppFileList + ii, '\\') + 1, finddata.cFileName);
574
575 if (strcmp(pstrPathName, *ppFileList + ii) == 0)
576 *pFileIndex = i;
577
578 ii += MAX_PATH;
579 i++;
580
581 bOk = FindNextFile(hFind, &finddata);
582 }
583 FindClose(hFind);
584
585 /* finally we must sort the file-list */
586
587 for (i = 0; i < *pFileCount - 1; i++)
588 {
589 ii = i * MAX_PATH;
590 for (j = i+1; j < *pFileCount; j++)
591 {
592 jj = j * MAX_PATH;
593 if (strcmp (*ppFileList + ii, *ppFileList + jj) > 0)
594 {
595 strcpy (szTmp, *ppFileList + jj);
596 strcpy (*ppFileList + jj, *ppFileList + ii);
597 strcpy (*ppFileList + ii, szTmp);
598
599 /* check if this was the current image that we moved */
600
601 if (*pFileIndex == i)
602 *pFileIndex = j;
603 else
604 if (*pFileIndex == j)
605 *pFileIndex = i;
606 }
607 }
608 }
609
610 return TRUE;
611 }
612
613 /*----------------
614 * SearchPngList
615 *----------------
616 */
617
SearchPngList(TCHAR * pFileList,int FileCount,int * pFileIndex,PTSTR pstrPrevName,PTSTR pstrNextName)618 BOOL SearchPngList (
619 TCHAR *pFileList, int FileCount, int *pFileIndex,
620 PTSTR pstrPrevName, PTSTR pstrNextName)
621 {
622 if (FileCount > 0)
623 {
624 /* get previous entry */
625
626 if (pstrPrevName != NULL)
627 {
628 if (*pFileIndex > 0)
629 *pFileIndex -= 1;
630 else
631 *pFileIndex = FileCount - 1;
632
633 strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
634 }
635
636 /* get next entry */
637
638 if (pstrNextName != NULL)
639 {
640 if (*pFileIndex < FileCount - 1)
641 *pFileIndex += 1;
642 else
643 *pFileIndex = 0;
644
645 strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
646 }
647
648 return TRUE;
649 }
650 else
651 {
652 return FALSE;
653 }
654 }
655
656 /*-----------------
657 * LoadImageFile
658 *-----------------
659 */
660
LoadImageFile(HWND hwnd,PTSTR pstrPathName,png_byte ** ppbImage,int * pxImgSize,int * pyImgSize,int * piChannels,png_color * pBkgColor)661 BOOL LoadImageFile (HWND hwnd, PTSTR pstrPathName,
662 png_byte **ppbImage, int *pxImgSize, int *pyImgSize,
663 int *piChannels, png_color *pBkgColor)
664 {
665 static TCHAR szTmp [MAX_PATH];
666
667 /* if there's an existing PNG, free the memory */
668
669 if (*ppbImage)
670 {
671 free (*ppbImage);
672 *ppbImage = NULL;
673 }
674
675 /* Load the entire PNG into memory */
676
677 SetCursor (LoadCursor (NULL, IDC_WAIT));
678 ShowCursor (TRUE);
679
680 PngLoadImage (pstrPathName, ppbImage, pxImgSize, pyImgSize, piChannels,
681 pBkgColor);
682
683 ShowCursor (FALSE);
684 SetCursor (LoadCursor (NULL, IDC_ARROW));
685
686 if (*ppbImage != NULL)
687 {
688 sprintf (szTmp, "VisualPng - %s", strrchr(pstrPathName, '\\') + 1);
689 SetWindowText (hwnd, szTmp);
690 }
691 else
692 {
693 MessageBox (hwnd, TEXT ("Error in loading the PNG image"),
694 szProgName, MB_ICONEXCLAMATION | MB_OK);
695 return FALSE;
696 }
697
698 return TRUE;
699 }
700
701 /*----------------
702 * DisplayImage
703 *----------------
704 */
DisplayImage(HWND hwnd,BYTE ** ppDib,BYTE ** ppDiData,int cxWinSize,int cyWinSize,BYTE * pbImage,int cxImgSize,int cyImgSize,int cImgChannels,BOOL bStretched)705 BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
706 BYTE **ppDiData, int cxWinSize, int cyWinSize,
707 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
708 BOOL bStretched)
709 {
710 BYTE *pDib = *ppDib;
711 BYTE *pDiData = *ppDiData;
712 /* BITMAPFILEHEADER *pbmfh; */
713 BITMAPINFOHEADER *pbmih;
714 WORD wDIRowBytes;
715 png_color bkgBlack = {0, 0, 0};
716 png_color bkgGray = {127, 127, 127};
717 png_color bkgWhite = {255, 255, 255};
718
719 /* allocate memory for the Device Independent bitmap */
720
721 wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;
722
723 if (pDib)
724 {
725 free (pDib);
726 pDib = NULL;
727 }
728
729 if (cyWinSize > ((size_t)(-1))/wDIRowBytes) {
730 {
731 MessageBox (hwnd, TEXT ("Visual PNG: image is too big");
732 }
733 if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
734 wDIRowBytes * cyWinSize)))
735 {
736 MessageBox (hwnd, TEXT ("Error in displaying the PNG image"),
737 szProgName, MB_ICONEXCLAMATION | MB_OK);
738 *ppDib = pDib = NULL;
739 return FALSE;
740 }
741 *ppDib = pDib;
742 memset (pDib, 0, sizeof(BITMAPINFOHEADER));
743
744 /* initialize the dib-structure */
745
746 pbmih = (BITMAPINFOHEADER *) pDib;
747 pbmih->biSize = sizeof(BITMAPINFOHEADER);
748 pbmih->biWidth = cxWinSize;
749 pbmih->biHeight = -((long) cyWinSize);
750 pbmih->biPlanes = 1;
751 pbmih->biBitCount = 24;
752 pbmih->biCompression = 0;
753 pDiData = pDib + sizeof(BITMAPINFOHEADER);
754 *ppDiData = pDiData;
755
756 /* first fill bitmap with gray and image border */
757
758 InitBitmap (pDiData, cxWinSize, cyWinSize);
759
760 /* then fill bitmap with image */
761
762 if (pbImage)
763 {
764 FillBitmap (
765 pDiData, cxWinSize, cyWinSize,
766 pbImage, cxImgSize, cyImgSize, cImgChannels,
767 bStretched);
768 }
769
770 return TRUE;
771 }
772
773 /*--------------
774 * InitBitmap
775 *--------------
776 */
777 BOOL InitBitmap (BYTE *pDiData, int cxWinSize, int cyWinSize)
778 {
779 BYTE *dst;
780 int x, y, col;
781
782 /* initialize the background with gray */
783
784 dst = pDiData;
785 for (y = 0; y < cyWinSize; y++)
786 {
787 col = 0;
788 for (x = 0; x < cxWinSize; x++)
789 {
790 /* fill with GRAY */
791 *dst++ = 127;
792 *dst++ = 127;
793 *dst++ = 127;
794 col += 3;
795 }
796 /* rows start on 4 byte boundaries */
797 while ((col % 4) != 0)
798 {
799 dst++;
800 col++;
801 }
802 }
803
804 return TRUE;
805 }
806
807 /*--------------
808 * FillBitmap
809 *--------------
810 */
811 BOOL FillBitmap (
812 BYTE *pDiData, int cxWinSize, int cyWinSize,
813 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
814 BOOL bStretched)
815 {
816 BYTE *pStretchedImage;
817 BYTE *pImg;
818 BYTE *src, *dst;
819 BYTE r, g, b, a;
820 const int cDIChannels = 3;
821 WORD wImgRowBytes;
822 WORD wDIRowBytes;
823 int cxNewSize, cyNewSize;
824 int cxImgPos, cyImgPos;
825 int xImg, yImg;
826 int xWin, yWin;
827 int xOld, yOld;
828 int xNew, yNew;
829
830 if (bStretched)
831 {
832 cxNewSize = cxWinSize - 2 * MARGIN;
833 cyNewSize = cyWinSize - 2 * MARGIN;
834
835 /* stretch the image to it's window determined size */
836
837 /* the following two are mathematically the same, but the first
838 * has side-effects because of rounding
839 */
840 /* if ((cyNewSize / cxNewSize) > (cyImgSize / cxImgSize)) */
841 if ((cyNewSize * cxImgSize) > (cyImgSize * cxNewSize))
842 {
843 cyNewSize = cxNewSize * cyImgSize / cxImgSize;
844 cxImgPos = MARGIN;
845 cyImgPos = (cyWinSize - cyNewSize) / 2;
846 }
847 else
848 {
849 cxNewSize = cyNewSize * cxImgSize / cyImgSize;
850 cyImgPos = MARGIN;
851 cxImgPos = (cxWinSize - cxNewSize) / 2;
852 }
853
854 if (cyNewSize > ((size_t)(-1))/(cImgChannels * cxNewSize)) {
855 {
856 MessageBox (hwnd, TEXT ("Visual PNG: stretched image is too big");
857 }
858 pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
859 pImg = pStretchedImage;
860
861 for (yNew = 0; yNew < cyNewSize; yNew++)
862 {
863 yOld = yNew * cyImgSize / cyNewSize;
864 for (xNew = 0; xNew < cxNewSize; xNew++)
865 {
866 xOld = xNew * cxImgSize / cxNewSize;
867
868 r = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 0);
869 g = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 1);
870 b = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 2);
871 *pImg++ = r;
872 *pImg++ = g;
873 *pImg++ = b;
874 if (cImgChannels == 4)
875 {
876 a = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld)
877 + 3);
878 *pImg++ = a;
879 }
880 }
881 }
882
883 /* calculate row-bytes */
884
885 wImgRowBytes = cImgChannels * cxNewSize;
886 wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
887
888 /* copy image to screen */
889
890 for (yImg = 0, yWin = cyImgPos; yImg < cyNewSize; yImg++, yWin++)
891 {
892 if (yWin >= cyWinSize - cyImgPos)
893 break;
894 src = pStretchedImage + yImg * wImgRowBytes;
895 dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
896
897 for (xImg = 0, xWin = cxImgPos; xImg < cxNewSize; xImg++, xWin++)
898 {
899 if (xWin >= cxWinSize - cxImgPos)
900 break;
901 r = *src++;
902 g = *src++;
903 b = *src++;
904 *dst++ = b; /* note the reverse order */
905 *dst++ = g;
906 *dst++ = r;
907 if (cImgChannels == 4)
908 {
909 a = *src++;
910 }
911 }
912 }
913
914 /* free memory */
915
916 if (pStretchedImage != NULL)
917 {
918 free (pStretchedImage);
919 pStretchedImage = NULL;
920 }
921
922 }
923
924 /* process the image not-stretched */
925
926 else
927 {
928 /* calculate the central position */
929
930 cxImgPos = (cxWinSize - cxImgSize) / 2;
931 cyImgPos = (cyWinSize - cyImgSize) / 2;
932
933 /* check for image larger than window */
934
935 if (cxImgPos < MARGIN)
936 cxImgPos = MARGIN;
937 if (cyImgPos < MARGIN)
938 cyImgPos = MARGIN;
939
940 /* calculate both row-bytes */
941
942 wImgRowBytes = cImgChannels * cxImgSize;
943 wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
944
945 /* copy image to screen */
946
947 for (yImg = 0, yWin = cyImgPos; yImg < cyImgSize; yImg++, yWin++)
948 {
949 if (yWin >= cyWinSize - MARGIN)
950 break;
951 src = pbImage + yImg * wImgRowBytes;
952 dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
953
954 for (xImg = 0, xWin = cxImgPos; xImg < cxImgSize; xImg++, xWin++)
955 {
956 if (xWin >= cxWinSize - MARGIN)
957 break;
958 r = *src++;
959 g = *src++;
960 b = *src++;
961 *dst++ = b; /* note the reverse order */
962 *dst++ = g;
963 *dst++ = r;
964 if (cImgChannels == 4)
965 {
966 a = *src++;
967 }
968 }
969 }
970 }
971
972 return TRUE;
973 }
974
975 /*-----------------
976 * end of source
977 *-----------------
978 */
979