1 //------------------------------------
2 // VisualPng.C -- Shows a PNG image
3 //------------------------------------
5 // Copyright 2000, Willem van Schaik. For conditions of distribution and
6 // use, see the copyright/license/disclaimer notice in png.h
12 #define PROGNAME "VisualPng"
13 #define LONGNAME "Win32 Viewer for PNG-files"
14 #define VERSION "1.0 of 2000 June 07"
27 // application includes
35 // function prototypes
37 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
38 BOOL CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
40 BOOL CenterAbout (HWND hwndChild, HWND hwndParent);
42 BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
45 BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,
46 PTSTR pstrPrevName, PTSTR pstrNextName);
48 BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,
49 png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,
50 png_color *pBkgColor);
52 BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
53 BYTE **ppDiData, int cxWinSize, int cyWinSize,
54 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
58 BYTE *pDiData, int cxWinSize, int cyWinSize);
61 BYTE *pDiData, int cxWinSize, int cyWinSize,
62 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
65 // a few global variables
67 static char *szProgName = PROGNAME;
68 static char *szAppName = LONGNAME;
69 static char *szIconName = PROGNAME;
70 static char szCmdFileName [MAX_PATH];
74 int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
75 PSTR szCmdLine, int iCmdShow)
81 int ixBorders, iyBorders;
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;
94 if (!RegisterClass (&wndclass))
96 MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),
97 szProgName, MB_ICONERROR);
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);
106 strcpy (szCmdFileName, szCmdLine);
108 strcpy (szCmdFileName, "");
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? */
119 hwnd = CreateWindow (szProgName, szAppName,
121 CW_USEDEFAULT, CW_USEDEFAULT,
122 512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,
123 // CW_USEDEFAULT, CW_USEDEFAULT,
124 NULL, NULL, hInstance, NULL);
126 ShowWindow (hwnd, iCmdShow);
129 hAccel = LoadAccelerators (hInstance, szProgName);
131 while (GetMessage (&msg, NULL, 0, 0))
133 if (!TranslateAccelerator (hwnd, hAccel, &msg))
135 TranslateMessage (&msg);
136 DispatchMessage (&msg);
142 LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
145 static HINSTANCE hInstance ;
147 static PAINTSTRUCT ps;
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};
158 static BOOL bStretched = TRUE;
160 static BYTE *pDib = NULL;
161 static BYTE *pDiData = NULL;
163 static TCHAR szImgPathName [MAX_PATH];
164 static TCHAR szTitleName [MAX_PATH];
166 static TCHAR *pPngFileList = NULL;
167 static int iPngFileCount;
168 static int iPngFileIndex;
175 hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
176 PngFileInitialize (hwnd);
178 strcpy (szImgPathName, "");
180 // in case we process file given on command-line
182 if (szCmdFileName[0] != '\0')
184 strcpy (szImgPathName, szCmdFileName);
186 // read the other png-files in the directory for later
187 // next/previous commands
189 BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
192 // load the image from file
194 if (!LoadImageFile (hwnd, szImgPathName,
195 &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
198 // invalidate the client area for later update
200 InvalidateRect (hwnd, NULL, TRUE);
202 // display the PNG into the DIBitmap
204 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
205 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
211 cxWinSize = LOWORD (lParam);
212 cyWinSize = HIWORD (lParam);
214 // invalidate the client area for later update
216 InvalidateRect (hwnd, NULL, TRUE);
218 // display the PNG into the DIBitmap
220 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
221 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
225 case WM_INITMENUPOPUP:
226 hMenu = GetMenu (hwnd);
229 EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);
231 EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);
236 hMenu = GetMenu (hwnd);
238 switch (LOWORD (wParam))
242 // show the File Open dialog box
244 if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))
247 // read the other png-files in the directory for later
248 // next/previous commands
250 BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
253 // load the image from file
255 if (!LoadImageFile (hwnd, szImgPathName,
256 &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
259 // invalidate the client area for later update
261 InvalidateRect (hwnd, NULL, TRUE);
263 // display the PNG into the DIBitmap
265 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
266 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
272 // show the File Save dialog box
274 if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))
277 // save the PNG to a disk file
279 SetCursor (LoadCursor (NULL, IDC_WAIT));
282 bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,
286 SetCursor (LoadCursor (NULL, IDC_ARROW));
289 MessageBox (hwnd, TEXT ("Error in saving the PNG image"),
290 szProgName, MB_ICONEXCLAMATION | MB_OK);
295 // read next entry in the directory
297 if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
298 NULL, szImgPathName))
300 if (strcmp (szImgPathName, "") == 0)
303 // load the image from file
305 if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
306 &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
309 // invalidate the client area for later update
311 InvalidateRect (hwnd, NULL, TRUE);
313 // display the PNG into the DIBitmap
315 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
316 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
321 case IDM_FILE_PREVIOUS:
323 // read previous entry in the directory
325 if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
326 szImgPathName, NULL))
329 if (strcmp (szImgPathName, "") == 0)
332 // load the image from file
334 if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
335 &cyImgSize, &cImgChannels, &bkgColor))
338 // invalidate the client area for later update
340 InvalidateRect (hwnd, NULL, TRUE);
342 // display the PNG into the DIBitmap
344 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
345 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
352 // more cleanup needed...
364 if (pPngFileList != NULL)
376 case IDM_OPTIONS_STRETCH:
377 bStretched = !bStretched;
379 CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);
381 CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);
383 // invalidate the client area for later update
385 InvalidateRect (hwnd, NULL, TRUE);
387 // display the PNG into the DIBitmap
389 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
390 pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
395 DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;
403 hdc = BeginPaint (hwnd, &ps);
406 SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,
407 0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);
409 EndPaint (hwnd, &ps);
423 return DefWindowProc (hwnd, message, wParam, lParam);
426 BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,
427 WPARAM wParam, LPARAM lParam)
432 ShowWindow (hDlg, SW_HIDE);
433 CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));
434 ShowWindow (hDlg, SW_SHOW);
438 switch (LOWORD (wParam))
442 EndDialog (hDlg, 0) ;
454 BOOL CenterAbout (HWND hwndChild, HWND hwndParent)
456 RECT rChild, rParent, rWorkArea;
457 int wChild, hChild, wParent, hParent;
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;
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;
471 // Get the limits of the 'workarea'
472 bResult = SystemParametersInfo(
473 SPI_GETWORKAREA, // system parameter to query or set
478 rWorkArea.left = rWorkArea.top = 0;
479 rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);
480 rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);
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;
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;
499 // Set it, and return
500 return SetWindowPos (hwndChild, NULL, xNew, yNew, 0, 0, SWP_NOSIZE |
508 BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
511 static TCHAR szImgPathName [MAX_PATH];
512 static TCHAR szImgFileName [MAX_PATH];
513 static TCHAR szImgFindName [MAX_PATH];
515 WIN32_FIND_DATA finddata;
518 static TCHAR szTmp [MAX_PATH];
523 // free previous file-list
525 if (*ppFileList != NULL)
531 // extract foldername, filename and search-name
533 strcpy (szImgPathName, pstrPathName);
534 strcpy (szImgFileName, strrchr (pstrPathName, '\\') + 1);
536 strcpy (szImgFindName, szImgPathName);
537 *(strrchr (szImgFindName, '\\') + 1) = '\0';
538 strcat (szImgFindName, "*.png");
540 // first cycle: count number of files in directory for memory allocation
544 hFind = FindFirstFile(szImgFindName, &finddata);
545 bOk = (hFind != (HANDLE) -1);
550 bOk = FindNextFile(hFind, &finddata);
554 // allocation memory for file-list
556 *ppFileList = (TCHAR *) malloc (*pFileCount * MAX_PATH);
558 // second cycle: read directory and store filenames in file-list
560 hFind = FindFirstFile(szImgFindName, &finddata);
561 bOk = (hFind != (HANDLE) -1);
567 strcpy (*ppFileList + ii, szImgPathName);
568 strcpy (strrchr(*ppFileList + ii, '\\') + 1, finddata.cFileName);
570 if (strcmp(pstrPathName, *ppFileList + ii) == 0)
576 bOk = FindNextFile(hFind, &finddata);
580 // finally we must sort the file-list
582 for (i = 0; i < *pFileCount - 1; i++)
585 for (j = i+1; j < *pFileCount; j++)
588 if (strcmp (*ppFileList + ii, *ppFileList + jj) > 0)
590 strcpy (szTmp, *ppFileList + jj);
591 strcpy (*ppFileList + jj, *ppFileList + ii);
592 strcpy (*ppFileList + ii, szTmp);
594 // check if this was the current image that we moved
596 if (*pFileIndex == i)
599 if (*pFileIndex == j)
613 TCHAR *pFileList, int FileCount, int *pFileIndex,
614 PTSTR pstrPrevName, PTSTR pstrNextName)
618 // get previous entry
620 if (pstrPrevName != NULL)
625 *pFileIndex = FileCount - 1;
627 strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
632 if (pstrNextName != NULL)
634 if (*pFileIndex < FileCount - 1)
639 strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
654 BOOL LoadImageFile (HWND hwnd, PTSTR pstrPathName,
655 png_byte **ppbImage, int *pxImgSize, int *pyImgSize,
656 int *piChannels, png_color *pBkgColor)
658 static TCHAR szTmp [MAX_PATH];
660 // if there's an existing PNG, free the memory
668 // Load the entire PNG into memory
670 SetCursor (LoadCursor (NULL, IDC_WAIT));
673 PngLoadImage (pstrPathName, ppbImage, pxImgSize, pyImgSize, piChannels,
677 SetCursor (LoadCursor (NULL, IDC_ARROW));
679 if (*ppbImage != NULL)
681 sprintf (szTmp, "VisualPng - %s", strrchr(pstrPathName, '\\') + 1);
682 SetWindowText (hwnd, szTmp);
686 MessageBox (hwnd, TEXT ("Error in loading the PNG image"),
687 szProgName, MB_ICONEXCLAMATION | MB_OK);
698 BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
699 BYTE **ppDiData, int cxWinSize, int cyWinSize,
700 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
704 BYTE *pDiData = *ppDiData;
705 // BITMAPFILEHEADER *pbmfh;
706 BITMAPINFOHEADER *pbmih;
708 png_color bkgBlack = {0, 0, 0};
709 png_color bkgGray = {127, 127, 127};
710 png_color bkgWhite = {255, 255, 255};
712 // allocate memory for the Device Independant bitmap
714 wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;
722 if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
723 wDIRowBytes * cyWinSize)))
725 MessageBox (hwnd, TEXT ("Error in displaying the PNG image"),
726 szProgName, MB_ICONEXCLAMATION | MB_OK);
727 *ppDib = pDib = NULL;
731 memset (pDib, 0, sizeof(BITMAPINFOHEADER));
733 // initialize the dib-structure
735 pbmih = (BITMAPINFOHEADER *) pDib;
736 pbmih->biSize = sizeof(BITMAPINFOHEADER);
737 pbmih->biWidth = cxWinSize;
738 pbmih->biHeight = -((long) cyWinSize);
740 pbmih->biBitCount = 24;
741 pbmih->biCompression = 0;
742 pDiData = pDib + sizeof(BITMAPINFOHEADER);
745 // first fill bitmap with gray and image border
747 InitBitmap (pDiData, cxWinSize, cyWinSize);
749 // then fill bitmap with image
754 pDiData, cxWinSize, cyWinSize,
755 pbImage, cxImgSize, cyImgSize, cImgChannels,
766 BOOL InitBitmap (BYTE *pDiData, int cxWinSize, int cyWinSize)
771 // initialize the background with gray
774 for (y = 0; y < cyWinSize; y++)
777 for (x = 0; x < cxWinSize; x++)
785 // rows start on 4 byte boundaries
786 while ((col % 4) != 0)
801 BYTE *pDiData, int cxWinSize, int cyWinSize,
802 BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
805 BYTE *pStretchedImage;
809 const int cDIChannels = 3;
812 int cxNewSize, cyNewSize;
813 int cxImgPos, cyImgPos;
821 cxNewSize = cxWinSize - 2 * MARGIN;
822 cyNewSize = cyWinSize - 2 * MARGIN;
824 // stretch the image to it's window determined size
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))
831 cyNewSize = cxNewSize * cyImgSize / cxImgSize;
833 cyImgPos = (cyWinSize - cyNewSize) / 2;
837 cxNewSize = cyNewSize * cxImgSize / cyImgSize;
839 cxImgPos = (cxWinSize - cxNewSize) / 2;
842 pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
843 pImg = pStretchedImage;
845 for (yNew = 0; yNew < cyNewSize; yNew++)
847 yOld = yNew * cyImgSize / cyNewSize;
848 for (xNew = 0; xNew < cxNewSize; xNew++)
850 xOld = xNew * cxImgSize / cxNewSize;
852 r = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 0);
853 g = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 1);
854 b = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 2);
858 if (cImgChannels == 4)
860 a = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld)
867 // calculate row-bytes
869 wImgRowBytes = cImgChannels * cxNewSize;
870 wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
872 // copy image to screen
874 for (yImg = 0, yWin = cyImgPos; yImg < cyNewSize; yImg++, yWin++)
876 if (yWin >= cyWinSize - cyImgPos)
878 src = pStretchedImage + yImg * wImgRowBytes;
879 dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
881 for (xImg = 0, xWin = cxImgPos; xImg < cxNewSize; xImg++, xWin++)
883 if (xWin >= cxWinSize - cxImgPos)
888 *dst++ = b; /* note the reverse order */
891 if (cImgChannels == 4)
900 if (pStretchedImage != NULL)
902 free (pStretchedImage);
903 pStretchedImage = NULL;
908 // process the image not-stretched
912 // calculate the central position
914 cxImgPos = (cxWinSize - cxImgSize) / 2;
915 cyImgPos = (cyWinSize - cyImgSize) / 2;
917 // check for image larger than window
919 if (cxImgPos < MARGIN)
921 if (cyImgPos < MARGIN)
924 // calculate both row-bytes
926 wImgRowBytes = cImgChannels * cxImgSize;
927 wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
929 // copy image to screen
931 for (yImg = 0, yWin = cyImgPos; yImg < cyImgSize; yImg++, yWin++)
933 if (yWin >= cyWinSize - MARGIN)
935 src = pbImage + yImg * wImgRowBytes;
936 dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
938 for (xImg = 0, xWin = cxImgPos; xImg < cxImgSize; xImg++, xWin++)
940 if (xWin >= cxWinSize - MARGIN)
945 *dst++ = b; /* note the reverse order */
948 if (cImgChannels == 4)