screenshot.c File Reference

#include "screenshot.h"

Include dependency graph for screenshot.c:

Go to the source code of this file.

Functions
static VOID	GetError (VOID)
static BOOL	DoWriteFile (PSCREENSHOT pScrSht, LPTSTR pstrFileName)
static BOOL	DoSaveFile (HWND hwnd, LPTSTR szFileName)
static BOOL	CaptureScreen (PSCREENSHOT pScrSht)
static BOOL	ConvertDDBtoDIB (PSCREENSHOT pScrSht)
int WINAPI	_tWinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR szCmdLine, int iCmdShow)

Function Documentation

_tWinMain()

int WINAPI _tWinMain	(	HINSTANCE	hInstance,
		HINSTANCE	hPrevInstance,
		LPTSTR	szCmdLine,
		int	iCmdShow
	)

Definition at line 341 of file screenshot.c.

{
    PSCREENSHOT pScrSht;
    TCHAR szFileName[MAX_PATH] = _T("");
 
    BOOL bFullScreen = TRUE;
 
    pScrSht = HeapAlloc(GetProcessHeap(),
                        0,
                        sizeof(SCREENSHOT));
    if (pScrSht == NULL)
        return -1;
 
    if (bFullScreen)
    {
        pScrSht->hSelf = GetDesktopWindow();
    }
    else
    {
        pScrSht->hSelf = GetForegroundWindow();
    }
 
    if (pScrSht->hSelf == NULL)
    {
        HeapFree(GetProcessHeap(),
                 0,
                 pScrSht);
 
        return -1;
    }
 
    if (CaptureScreen(pScrSht))
    {
        /* convert the DDB image to DIB */
        if(ConvertDDBtoDIB(pScrSht))
        {
            /* Get filename from user */
            if(DoSaveFile(pScrSht->hSelf, szFileName))
            {
                /* build the headers and write to file */
                DoWriteFile(pScrSht, szFileName);
            }
        }
    }
 
    /* cleanup */
    if (pScrSht->hSelf != NULL)
        ReleaseDC(pScrSht->hSelf, pScrSht->hDC);
    if (pScrSht->hBitmap != NULL)
        DeleteObject(pScrSht->hBitmap);
    if (pScrSht->lpbi != NULL)
        HeapFree(GetProcessHeap(),
                 0,
                 pScrSht->lpbi);
    if (pScrSht->lpvBits != NULL)
        HeapFree(GetProcessHeap(),
                 0,
                 pScrSht->lpvBits);
    if (pScrSht != NULL)
        HeapFree(GetProcessHeap(),
                 0,
                 pScrSht);
 
    return 0;
}

CaptureScreen()

static BOOL CaptureScreen ( PSCREENSHOT  pScrSht )

static

Definition at line 164 of file screenshot.c.

{
    HDC ScreenDC;
    RECT rect;
 
    /* get window resolution */
    //pScrSht->Width = GetSystemMetrics(SM_CXSCREEN);
    //pScrSht->Height = GetSystemMetrics(SM_CYSCREEN);
 
    GetWindowRect(pScrSht->hSelf, &rect);
    pScrSht->Width = rect.right - rect.left;
    pScrSht->Height = rect.bottom - rect.top;
 
    /* get a DC for the screen */
    if (!(ScreenDC = GetDC(pScrSht->hSelf)))
        return FALSE;
 
    /* get a bitmap handle for the screen
     * needed to convert to a DIB */
    pScrSht->hBitmap = CreateCompatibleBitmap(ScreenDC,
                                              pScrSht->Width,
                                              pScrSht->Height);
    if (pScrSht->hBitmap == NULL)
    {
        GetError();
        ReleaseDC(pScrSht->hSelf, ScreenDC);
        return FALSE;
    }
 
    /* get a DC compatable with the screen DC */
    if (!(pScrSht->hDC = CreateCompatibleDC(ScreenDC)))
    {
        GetError();
        ReleaseDC(pScrSht->hSelf, ScreenDC);
        return FALSE;
    }
 
    /* select the bitmap into the DC */
    SelectObject(pScrSht->hDC,
                 pScrSht->hBitmap);
 
    /* copy the screen DC to the bitmap */
    BitBlt(pScrSht->hDC,
           0,
           0,
           pScrSht->Width,
           pScrSht->Height,
           ScreenDC,
           0,
           0,
           SRCCOPY);
 
    /* we're finished with the screen DC */
    ReleaseDC(pScrSht->hSelf, ScreenDC);
 
    return TRUE;
}

Referenced by _tWinMain().

ConvertDDBtoDIB()

static BOOL ConvertDDBtoDIB ( PSCREENSHOT  pScrSht )

static

Definition at line 224 of file screenshot.c.

{
    INT Ret;
    BITMAP bitmap;
    WORD cClrBits;
 
 
/*
    / * can't call GetDIBits with hBitmap selected * /
    //SelectObject(hDC, hOldBitmap);
 
    / * let GetDIBits fill the lpbi structure by passing NULL pointer * /
    Ret = GetDIBits(hDC,
                    hBitmap,
                    0,
                    Height,
                    NULL,
                    lpbi,
                    DIB_RGB_COLORS);
    if (Ret == 0)
    {
        GetError();
        ReleaseDC(hwnd, hDC);
        HeapFree(GetProcessHeap(), 0, lpbi);
        return -1;
    }
*/
 
 
    if (!GetObjectW(pScrSht->hBitmap,
                    sizeof(BITMAP),
                    (LPTSTR)&bitmap))
    {
        GetError();
        return FALSE;
    }
 
    cClrBits = (WORD)(bitmap.bmPlanes * bitmap.bmBitsPixel);
    if (cClrBits == 1)
        cClrBits = 1;
    else if (cClrBits <= 4)
        cClrBits = 4;
    else if (cClrBits <= 8)
        cClrBits = 8;
    else if (cClrBits <= 16)
        cClrBits = 16;
    else if (cClrBits <= 24)
        cClrBits = 24;
    else cClrBits = 32;
 
  if (cClrBits != 24)
  {
    pScrSht->lpbi = (PBITMAPINFO) HeapAlloc(GetProcessHeap(),
                                            0,
                                            sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * (1 << cClrBits));
  }
  else
  {
    pScrSht->lpbi = (PBITMAPINFO) HeapAlloc(GetProcessHeap(),
                                            0,
                                            sizeof(BITMAPINFOHEADER));
  }
 
    if (!pScrSht->lpbi)
    {
        GetError();
        return FALSE;
    }
 
    pScrSht->lpbi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    pScrSht->lpbi->bmiHeader.biWidth = bitmap.bmWidth;
    pScrSht->lpbi->bmiHeader.biHeight = bitmap.bmHeight;
    pScrSht->lpbi->bmiHeader.biPlanes = bitmap.bmPlanes;
    pScrSht->lpbi->bmiHeader.biBitCount = bitmap.bmBitsPixel;
 
    if (cClrBits < 24)
        pScrSht->lpbi->bmiHeader.biClrUsed = (1 << cClrBits);
 
    pScrSht->lpbi->bmiHeader.biCompression = BI_RGB;
    pScrSht->lpbi->bmiHeader.biSizeImage = ((pScrSht->lpbi->bmiHeader.biWidth * cClrBits +31) & ~31) /8
                                           * pScrSht->lpbi->bmiHeader.biHeight;
 
    pScrSht->lpbi->bmiHeader.biClrImportant = 0;
 
 
    /* reserve memory to hold the screen bitmap */
    pScrSht->lpvBits = HeapAlloc(GetProcessHeap(),
                                 0,
                                 pScrSht->lpbi->bmiHeader.biSizeImage);
    if (pScrSht->lpvBits == NULL)
    {
        GetError();
        return FALSE;
    }
 
    /* convert the DDB to a DIB */
    Ret = GetDIBits(pScrSht->hDC,
                    pScrSht->hBitmap,
                    0,
                    pScrSht->Height,
                    pScrSht->lpvBits,
                    pScrSht->lpbi,
                    DIB_RGB_COLORS);
    if (Ret == 0)
    {
        GetError();
        return FALSE;
    }
 
    return TRUE;
 
}

Referenced by _tWinMain().

DoSaveFile()

static BOOL DoSaveFile ( HWND  hwnd, LPTSTR  szFileName  )

static

Definition at line 137 of file screenshot.c.

{
    OPENFILENAME ofn;
 
    static TCHAR Filter[] = _T("24 bit Bitmap (*.bmp,*.dib)\0*.bmp\0");
 
    ZeroMemory(&ofn, sizeof(ofn));
    ofn.lStructSize   = sizeof(OPENFILENAME);
    ofn.hwndOwner     = hwnd;
    ofn.nMaxFile      = MAX_PATH;
    ofn.nMaxFileTitle = MAX_PATH;
    ofn.lpstrDefExt   = _T("bmp");
    ofn.lpstrFilter = Filter;
    ofn.lpstrFile = szFileName;
    ofn.Flags = OFN_EXPLORER | OFN_PATHMUSTEXIST | OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;
 
    if (GetSaveFileName(&ofn))
        return TRUE;
 
    if (CommDlgExtendedError() != CDERR_GENERALCODES)
        MessageBox(NULL, _T("Save to file failed"), NULL, 0);
 
    return FALSE;
}

Referenced by _tWinMain().

DoWriteFile()

static BOOL DoWriteFile ( PSCREENSHOT  pScrSht, LPTSTR  pstrFileName  )

static

Definition at line 34 of file screenshot.c.

{
    BITMAPFILEHEADER bmfh;
    BOOL bSuccess;
    DWORD dwBytesWritten;
    HANDLE hFile;
    //INT PalEntries;
 
    hFile = CreateFile(pstrFileName,
                       GENERIC_WRITE,
                       0,
                       NULL,
                       CREATE_ALWAYS,
                       FILE_ATTRIBUTE_NORMAL,
                       NULL);
 
    if (hFile == INVALID_HANDLE_VALUE)
        return FALSE;
 
    /* write the BITMAPFILEHEADER to file */
    bmfh.bfType = *(WORD *)"BM";  // 0x4D 0x42
    bmfh.bfReserved1 = 0;
    bmfh.bfReserved2 = 0;
    bSuccess = WriteFile(hFile,
                         &bmfh,
                         sizeof(bmfh),
                         &dwBytesWritten,
                         NULL);
    if ((!bSuccess) || (dwBytesWritten < sizeof(bmfh)))
        goto fail;
 
    /* write the BITMAPINFOHEADER to file */
    bSuccess = WriteFile(hFile,
                         &pScrSht->lpbi->bmiHeader,
                         sizeof(BITMAPINFOHEADER),
                         &dwBytesWritten,
                         NULL);
    if ((!bSuccess) || (dwBytesWritten < sizeof(BITMAPINFOHEADER)))
        goto fail;
 
    /* calculate the size of the pallete * /
    if (pScrSht->lpbi->bmiHeader.biCompression == BI_BITFIELDS)
        PalEntries = 3;
    else
    {
        if (pScrSht->lpbi->bmiHeader.biBitCount <= 8)
            PalEntries = (INT)(1 << pScrSht->lpbi->bmiHeader.biBitCount);
        else
            PalEntries = 0;
    }
    if (pScrSht->lpbi->bmiHeader.biClrUsed)
        PalEntries = pScrSht->lpbi->bmiHeader.biClrUsed;
 
    / * write pallete to file * /
    if (PalEntries != 0)
    {
        bSuccess = WriteFile(hFile,
                             &pScrSht->lpbi->bmiColors,
                             PalEntries * sizeof(RGBQUAD),
                             &dwBytesWritten,
                             NULL);
        if ((!bSuccess) || (dwBytesWritten < PalEntries * sizeof(RGBQUAD)))
            goto fail;
    }
*/
    /* save the current file position at the bginning of the bitmap bits */
    bmfh.bfOffBits = SetFilePointer(hFile, 0, 0, FILE_CURRENT);
 
    /* write the bitmap bits to file */
    bSuccess = WriteFile(hFile,
                         pScrSht->lpvBits,
                         pScrSht->lpbi->bmiHeader.biSizeImage,
                         &dwBytesWritten,
                         NULL);
    if ((!bSuccess) || (dwBytesWritten < pScrSht->lpbi->bmiHeader.biSizeImage))
        goto fail;
 
    /* save the current file position at the final file size */
    bmfh.bfSize = SetFilePointer(hFile, 0, 0, FILE_CURRENT);
 
    /* rewrite the updated file headers */
    SetFilePointer(hFile, 0, 0, FILE_BEGIN);
    bSuccess = WriteFile(hFile,
                         &bmfh,
                         sizeof(bmfh),
                         &dwBytesWritten,
                         NULL);
    if ((!bSuccess) || (dwBytesWritten < sizeof(bmfh)))
        goto fail;
 
    return TRUE;
 
fail:
    GetError();
    if (hFile) CloseHandle(hFile);
    DeleteFile(pstrFileName);
    return FALSE;
 
}

Referenced by _tWinMain().

GetError()

static VOID GetError ( VOID  )

static

Definition at line 10 of file screenshot.c.

{
    LPVOID lpMsgBuf;
 
    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                  FORMAT_MESSAGE_FROM_SYSTEM |
                  FORMAT_MESSAGE_IGNORE_INSERTS,
                  NULL,
                  GetLastError(),
                  MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                  (LPTSTR) &lpMsgBuf,
                  0,
                  NULL );
 
    MessageBox(NULL,
               lpMsgBuf,
               _T("Error!"),
               MB_OK | MB_ICONERROR);
 
    LocalFree(lpMsgBuf);
}

Referenced by CaptureScreen(), ConvertDDBtoDIB(), and DoWriteFile().