//------------------------------------//  VisualPng.C -- Shows a PNG image//------------------------------------// Copyright 2000, Willem van Schaik.  For conditions of distribution and// use, see the copyright/license/disclaimer notice in png.h// switches// defines#define PROGNAME  "VisualPng"#define LONGNAME  "Win32 Viewer for PNG-files"#define VERSION   "1.0 of 2000 June 07"// constants#define MARGIN 8// standard includes#include <stdio.h>#include <stdlib.h>#include <string.h>#include <windows.h>// application includes#include "png.h"#include "pngfile.h"#include "resource.h"// macros// function prototypesLRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);BOOL    CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;BOOL CenterAbout (HWND hwndChild, HWND hwndParent);BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,        int *pFileIndex);BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,        PTSTR pstrPrevName, PTSTR pstrNextName);BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,        png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,        png_color *pBkgColor);BOOL DisplayImage (HWND hwnd, BYTE **ppDib,        BYTE **ppDiData, int cxWinSize, int cyWinSize,        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,        BOOL bStretched);BOOL InitBitmap (        BYTE *pDiData, int cxWinSize, int cyWinSize);BOOL FillBitmap (        BYTE *pDiData, int cxWinSize, int cyWinSize,        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,        BOOL bStretched);// a few global variablesstatic char *szProgName = PROGNAME;static char *szAppName = LONGNAME;static char *szIconName = PROGNAME;static char szCmdFileName [MAX_PATH];// MAIN routineint WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,                    PSTR szCmdLine, int iCmdShow){    HACCEL   hAccel;    HWND     hwnd;    MSG      msg;    WNDCLASS wndclass;    int ixBorders, iyBorders;    wndclass.style         = CS_HREDRAW | CS_VREDRAW;    wndclass.lpfnWndProc   = WndProc;    wndclass.cbClsExtra    = 0;    wndclass.cbWndExtra    = 0;    wndclass.hInstance     = hInstance;    wndclass.hIcon         = LoadIcon (hInstance, szIconName) ;    wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW);    wndclass.hbrBackground = NULL; // (HBRUSH) GetStockObject (GRAY_BRUSH);    wndclass.lpszMenuName  = szProgName;    wndclass.lpszClassName = szProgName;    if (!RegisterClass (&wndclass))    {        MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),            szProgName, MB_ICONERROR);        return 0;    }    // if filename given on commandline, store it    if ((szCmdLine != NULL) && (*szCmdLine != '\0'))        if (szCmdLine[0] == '"')            strncpy (szCmdFileName, szCmdLine + 1, strlen(szCmdLine) - 2);        else            strcpy (szCmdFileName, szCmdLine);    else        strcpy (szCmdFileName, "");    // calculate size of window-borders    ixBorders = 2 * (GetSystemMetrics (SM_CXBORDER) +                     GetSystemMetrics (SM_CXDLGFRAME));    iyBorders = 2 * (GetSystemMetrics (SM_CYBORDER) +                     GetSystemMetrics (SM_CYDLGFRAME)) +                     GetSystemMetrics (SM_CYCAPTION) +                     GetSystemMetrics (SM_CYMENUSIZE) +                     1; /* WvS: don't ask me why? */    hwnd = CreateWindow (szProgName, szAppName,        WS_OVERLAPPEDWINDOW,        CW_USEDEFAULT, CW_USEDEFAULT,        512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,//      CW_USEDEFAULT, CW_USEDEFAULT,        NULL, NULL, hInstance, NULL);    ShowWindow (hwnd, iCmdShow);    UpdateWindow (hwnd);    hAccel = LoadAccelerators (hInstance, szProgName);    while (GetMessage (&msg, NULL, 0, 0))    {        if (!TranslateAccelerator (hwnd, hAccel, &msg))        {            TranslateMessage (&msg);            DispatchMessage (&msg);        }    }    return msg.wParam;}LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,        LPARAM lParam){    static HINSTANCE          hInstance ;    static HDC                hdc;    static PAINTSTRUCT        ps;    static HMENU              hMenu;    static BITMAPFILEHEADER  *pbmfh;    static BITMAPINFOHEADER  *pbmih;    static BYTE              *pbImage;    static int                cxWinSize, cyWinSize;    static int                cxImgSize, cyImgSize;    static int                cImgChannels;    static png_color          bkgColor = {127, 127, 127};    static BOOL               bStretched = TRUE;    static BYTE              *pDib = NULL;    static BYTE              *pDiData = NULL;    static TCHAR              szImgPathName [MAX_PATH];    static TCHAR              szTitleName [MAX_PATH];    static TCHAR             *pPngFileList = NULL;    static int                iPngFileCount;    static int                iPngFileIndex;    BOOL                      bOk;    switch (message)    {    case WM_CREATE:        hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;        PngFileInitialize (hwnd);        strcpy (szImgPathName, "");        // in case we process file given on command-line        if (szCmdFileName[0] != '\0')        {            strcpy (szImgPathName, szCmdFileName);            // read the other png-files in the directory for later            // next/previous commands            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,                          &iPngFileIndex);            // load the image from file            if (!LoadImageFile (hwnd, szImgPathName,                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))                return 0;            // invalidate the client area for later update            InvalidateRect (hwnd, NULL, TRUE);            // display the PNG into the DIBitmap            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);        }        return 0;    case WM_SIZE:        cxWinSize = LOWORD (lParam);        cyWinSize = HIWORD (lParam);        // invalidate the client area for later update        InvalidateRect (hwnd, NULL, TRUE);        // display the PNG into the DIBitmap        DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,            pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);        return 0;    case WM_INITMENUPOPUP:        hMenu = GetMenu (hwnd);        if (pbImage)            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);        else            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);        return 0;    case WM_COMMAND:        hMenu = GetMenu (hwnd);        switch (LOWORD (wParam))        {        case IDM_FILE_OPEN:            // show the File Open dialog box            if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))                return 0;            // read the other png-files in the directory for later            // next/previous commands            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,                          &iPngFileIndex);            // load the image from file            if (!LoadImageFile (hwnd, szImgPathName,                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))                return 0;            // invalidate the client area for later update            InvalidateRect (hwnd, NULL, TRUE);            // display the PNG into the DIBitmap            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);            return 0;        case IDM_FILE_SAVE:            // show the File Save dialog box            if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))                return 0;            // save the PNG to a disk file            SetCursor (LoadCursor (NULL, IDC_WAIT));            ShowCursor (TRUE);            bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,                  bkgColor);            ShowCursor (FALSE);            SetCursor (LoadCursor (NULL, IDC_ARROW));            if (!bOk)                MessageBox (hwnd, TEXT ("Error in saving the PNG image"),                szProgName, MB_ICONEXCLAMATION | MB_OK);            return 0;        case IDM_FILE_NEXT:            // read next entry in the directory            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,                NULL, szImgPathName))            {                if (strcmp (szImgPathName, "") == 0)                    return 0;                                // load the image from file                                if (!LoadImageFile (hwnd, szImgPathName, &pbImage,                        &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))                    return 0;                                // invalidate the client area for later update                                InvalidateRect (hwnd, NULL, TRUE);                                // display the PNG into the DIBitmap                                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);            }                        return 0;        case IDM_FILE_PREVIOUS:            // read previous entry in the directory            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,                szImgPathName, NULL))            {                                if (strcmp (szImgPathName, "") == 0)                    return 0;                                // load the image from file                                if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,                    &cyImgSize, &cImgChannels, &bkgColor))                    return 0;                                // invalidate the client area for later update                                InvalidateRect (hwnd, NULL, TRUE);                                // display the PNG into the DIBitmap                                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);            }            return 0;        case IDM_FILE_EXIT:            // more cleanup needed...            // free image buffer            if (pDib != NULL)            {                free (pDib);                pDib = NULL;            }            // free file-list            if (pPngFileList != NULL)            {                free (pPngFileList);                pPngFileList = NULL;            }            // let's go ...            exit (0);            return 0;        case IDM_OPTIONS_STRETCH:            bStretched = !bStretched;            if (bStretched)                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);            else                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);            // invalidate the client area for later update            InvalidateRect (hwnd, NULL, TRUE);            // display the PNG into the DIBitmap            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);            return 0;        case IDM_HELP_ABOUT:            DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;            return 0;        } // end switch        break;    case WM_PAINT:        hdc = BeginPaint (hwnd, &ps);        if (pDib)            SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,                0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);        EndPaint (hwnd, &ps);        return 0;    case WM_DESTROY:        if (pbmfh)        {            free (pbmfh);            pbmfh = NULL;        }        PostQuitMessage (0);        return 0;    }    return DefWindowProc (hwnd, message, wParam, lParam);}BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,                            WPARAM wParam, LPARAM lParam){     switch (message)     {     case WM_INITDIALOG :          ShowWindow (hDlg, SW_HIDE);          CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));          ShowWindow (hDlg, SW_SHOW);          return TRUE ;     case WM_COMMAND :          switch (LOWORD (wParam))          {          case IDOK :          case IDCANCEL :               EndDialog (hDlg, 0) ;               return TRUE ;          }          break ;     }     return FALSE ;}//---------------//  CenterAbout//---------------BOOL CenterAbout (HWND hwndChild, HWND hwndParent){   RECT    rChild, rParent, rWorkArea;   int     wChild, hChild, wParent, hParent;   int     xNew, yNew;   BOOL  bResult;   // Get the Height and Width of the child window   GetWindowRect (hwndChild, &rChild);   wChild = rChild.right - rChild.left;   hChild = rChild.bottom - rChild.top;   // Get the Height and Width of the parent window   GetWindowRect (hwndParent, &rParent);   wParent = rParent.right - rParent.left;   hParent = rParent.bottom - rParent.top;   // Get the limits of the 'workarea'   bResult = SystemParametersInfo(      SPI_GETWORKAREA,  // system parameter to query or set      sizeof(RECT),      &rWorkArea,      0);   if (!bResult) {      rWorkArea.left = rWorkArea.top = 0;      rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);      rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);   }