Thread: Istream::Release access violation? [C++]

Originally Posted by BobS0327

Give this a try...

Code:

LPPICTURE gpPicture; 


HBITMAP getFromInternet(std::string gal)
{

    HBITMAP    hBitmap;
    HINTERNET      hInternet = InternetOpen( "GINA: Version 0.1", INTERNET_OPEN_TYPE_DIRECT, NULL, 0,0);

    std::string temp = gal  + ".overview.jpg";
    gal = "http://www.imperialconflict.com/images/Galaxies/";
    gal += temp;
    MessageBox(NULL,gal.c_str(),"",MB_OK);
    //get size of file
    HINTERNET     hFile = InternetOpenUrl(hInternet, gal.c_str(), NULL, 0, 0, 0);
    DWORD sizeBuffer;
    DWORD length = sizeof(sizeBuffer);
    BYTE *buffer = NULL;

    bool succeeds = HttpQueryInfo(hFile, HTTP_QUERY_CONTENT_LENGTH | HTTP_QUERY_FLAG_NUMBER, (LPVOID)&sizeBuffer, &length, NULL);
    if (!succeeds)
    {
        throw "Unable to fetch map";
        return (HBITMAP) NULL;
    }
    buffer = new BYTE[sizeBuffer];

    //initialize all elements to 0
    for (int i = 0; i < sizeBuffer; i++)
        buffer[i] = 0;

    LPVOID pvData = NULL; 
    HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, sizeBuffer); 
    pvData = GlobalLock(hGlobal); 
    DWORD bytesRead;
    DWORD bytesToRead = sizeBuffer;
    if (hFile)
    {
        InternetReadFile(hFile, pvData, bytesToRead, &bytesRead);
    }
    else
        throw "Unable to grab overview image";

    GlobalUnlock(hGlobal); 
    CloseHandle(hFile); 
    LPSTREAM pstm = NULL; 
    // create IStream* from global memory 
    HRESULT hr = CreateStreamOnHGlobal(hGlobal, TRUE, &pstm); 
    // Create IPicture from image file 
    if (gpPicture) 
        gpPicture->Release(); 
    hr = OleLoadPicture(pstm, sizeBuffer, FALSE, IID_IPicture, (LPVOID *)&gpPicture); 
    pstm->Release(); 
    gpPicture-> get_Handle ((OLE_HANDLE *) & hBitmap); 
    hBitmap = (HBITMAP) CopyImage (hBitmap, IMAGE_BITMAP, 0,0,0); 
    InternetCloseHandle(hFile);
    InternetCloseHandle(hInternet);
    return hBitmap;
}

Be advised that reading the pixels is not as simple and straighforward as you may think it is.

Wow these have all been great responses. Unfortunately I've been away for a while as my system was rootkit-ed. It's been quite a battle to remove it. It disabled all current antivirus software and prevented the installation of new antivirus/antirootkit software.

Anyways I originally had something that looked like the above. Then I read on msnd that OleLoadPicture only supports bitmaps, gifs, and icons. That led me to libjpeg.

If you had a HBITMAP you could;

Create a temp DC ( CreateCompatibleDC(NULL) )
Select the HBITMAP into the DC (catching the returned default HBITMAP) with SelectObject()
loop thru the pixels with GetPixel(),
testing if each is 'blue' by using GetBValue(), GetRValue() and GetGValue()

clean up by
Selecting the default HBITMAP back into the DC
then DeleteDC() on the mem DC

That's perfect. I heard that GetPixel() can be a bit slow though. I'd need to check all the pixels in under 2 seconds. Do you think I could do that with a GetPixel() routine?

GDI+ on the other hand can load more of the "exotic" standard image formats such as JPG, PNG, TIFF and GIF.

Very very good post. I'd rather avoid GDI+. No particular reason. Just makes me 'icky'.

I'm still experimenting with source managers and libjpeg. I found a source manager at http://www.groupsrv.com/science/about102031.html but I don't know of it's licensing so I'm writing my own with that one as a reference.

I'll will post an update tomorrow. Thank you!

Anyways I originally had something that looked like the above. Then I read on msnd that OleLoadPicture only supports bitmaps, gifs, and icons. That led me to libjpeg.

Proof of concept code that proves OleLoadPicture supports jpeg. Right click on the image to change all the totally black pixels to totally white pixels.

Code:

#pragma comment( lib, "user32.lib" )
#pragma comment( lib, "olepro32.lib" )
#pragma comment( lib, "gdi32.lib" )
#pragma comment( lib, "ole32.lib" )
#pragma comment( lib, "Wininet.lib" )

#include <windows.h> 
#include <Wininet.h>
#include <olectl.h> 

#define COLORREF2RGB(Color) (Color & 0xff00) | ((Color >> 16) & 0xff) \
                                | ((Color << 16) & 0xff0000)

LPPICTURE gpPicture; 
HBITMAP hbm;

HBITMAP ChangePixels(HBITMAP hBmp,COLORREF cOldColor,COLORREF cNewColor,HDC hBitmapDC)
{
    HBITMAP hReturnBitmap = NULL;
    if (hBmp)
    {   
        HDC BufferDC=CreateCompatibleDC(NULL); 
        if (BufferDC)
        {
            HBITMAP hTempBitmap = (HBITMAP) NULL;
            if (hBitmapDC)
                if (hBmp == (HBITMAP)GetCurrentObject(hBitmapDC, OBJ_BITMAP))
                {
                    hTempBitmap = CreateBitmap(1, 1, 1, 1, NULL);
                    SelectObject(hBitmapDC, hTempBitmap);
                }
            HGDIOBJ PreviousBuffer=SelectObject(BufferDC,hBmp);
            HDC DirectDC=CreateCompatibleDC(NULL); 
            if (DirectDC)
            {
                BITMAP bm;
                GetObject(hBmp, sizeof(bm), &bm);
                BITMAPINFO BitmapInfo; 
                ZeroMemory(&BitmapInfo,sizeof(BITMAPINFO));
                BitmapInfo.bmiHeader.biSize=sizeof(BITMAPINFOHEADER);
                BitmapInfo.bmiHeader.biWidth=bm.bmWidth;
                BitmapInfo.bmiHeader.biHeight=bm.bmHeight;
                BitmapInfo.bmiHeader.biPlanes = 1;
                BitmapInfo.bmiHeader.biBitCount = 32;
                UINT * upPixels; 
                HBITMAP DirectBitmap= CreateDIBSection(DirectDC, (BITMAPINFO *)&BitmapInfo, DIB_RGB_COLORS,(void **)&upPixels, NULL, 0);
                if (DirectBitmap)
                {
                    HGDIOBJ PreviousObject=SelectObject(DirectDC, DirectBitmap);
                    BitBlt(DirectDC,0,0,bm.bmWidth,bm.bmHeight,BufferDC,0,0,SRCCOPY);                   
                    char   cNewColorRef=COLORREF2RGB(cNewColor);
                    for (int iIndex = ((bm.bmWidth*bm.bmHeight) - 1); iIndex >= 0; iIndex--)
                        if (upPixels[iIndex] == cOldColor) upPixels[iIndex] = cNewColorRef;
                    SelectObject(DirectDC,PreviousObject);
                    hReturnBitmap=DirectBitmap;
                }
                DeleteDC(DirectDC);
            }           
            if (hTempBitmap)
            {
                SelectObject(hBitmapDC, hBmp);
                DeleteObject(hTempBitmap);
            }
            SelectObject(BufferDC,PreviousBuffer);
            DeleteDC(BufferDC);
        }
    }
    return hReturnBitmap;
}

HBITMAP getFromInternet(char *pURL)
{
    HBITMAP    hBitmap;
    HINTERNET      hInternet = InternetOpen( "GINA: Version 0.1", INTERNET_OPEN_TYPE_DIRECT, NULL, 0,0);
    HINTERNET     hFile = InternetOpenUrl(hInternet, pURL, NULL, 0, 0, 0);
    DWORD sizeBuffer;
    DWORD length = sizeof(sizeBuffer);

    bool succeeds = HttpQueryInfo(hFile, HTTP_QUERY_CONTENT_LENGTH | HTTP_QUERY_FLAG_NUMBER, (LPVOID)&sizeBuffer, &length, NULL);
    if (!succeeds)
    {
        throw "Unable to fetch map";
        return (HBITMAP) NULL;
    }
    LPVOID pvData = NULL; 
    HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, sizeBuffer); 
    pvData = GlobalLock(hGlobal); 
    DWORD bytesRead;
    DWORD bytesToRead = sizeBuffer;
    if (hFile)
    {
        InternetReadFile(hFile, pvData, bytesToRead, &bytesRead);
    }
    else
        throw "Unable to grab overview image";
    GlobalUnlock(hGlobal); 
    CloseHandle(hFile); 
    LPSTREAM pstm = NULL; 
    // create IStream* from global memory 
    HRESULT hr = CreateStreamOnHGlobal(hGlobal, TRUE, &pstm); 
    // Create IPicture from image file 
    if (gpPicture) 
        gpPicture->Release(); 
    hr = OleLoadPicture(pstm, sizeBuffer, FALSE, IID_IPicture, (LPVOID *)&gpPicture); 
    pstm->Release(); 
    gpPicture-> get_Handle ((OLE_HANDLE *) & hBitmap); 
    hBitmap = (HBITMAP) CopyImage (hBitmap, IMAGE_BITMAP, 0,0,0); 
    InternetCloseHandle(hFile);
    InternetCloseHandle(hInternet);
    return hBitmap;
}

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ; 


int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) 
{ 
    static char szAppName[] = "JpegExample" ; 
    HWND hwnd; 
    MSG msg; 
    WNDCLASSEX wndclass; 

    int WinSize = 500; 
    int Left = 200; 
    int Top = 100; 

    wndclass.cbSize = sizeof (wndclass) ; 
    wndclass.style = CS_HREDRAW | CS_VREDRAW; 
    wndclass.lpfnWndProc = WndProc ; 
    wndclass.cbClsExtra = 0 ; 
    wndclass.cbWndExtra = 0 ; 
    wndclass.hInstance = hInstance ; 
    wndclass.hIcon = NULL ; 
    wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ; 
    wndclass.hbrBackground = (HBRUSH) (COLOR_WINDOW) ; 
    wndclass.lpszMenuName = NULL ; 
    wndclass.lpszClassName = szAppName ; 
    wndclass.hIconSm = NULL ; 

    RegisterClassEx (&wndclass) ; 

    hwnd = CreateWindow ( 
        szAppName, 
        "Jpeg Example",
        WS_OVERLAPPEDWINDOW, 
        Left, 
        Top , 
        WinSize, 
        WinSize, 
        NULL, 
        NULL, 
        hInstance, 
        NULL 
        ) ; 

    ShowWindow (hwnd, iCmdShow); 
    UpdateWindow (hwnd); 

    while (GetMessage (&msg, NULL, 0, 0)) 
    { 
        TranslateMessage (&msg) ; 
        DispatchMessage (&msg) ; 
    } 
    return msg.wParam ; 
} 


LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam) 
{ 
    HDC hdc,hMemDC; 
    PAINTSTRUCT ps; 
    BITMAP bm;
    RECT MainRc;
    POINT pt;
    COLORREF colNew, colOld;

    switch (iMsg) 
    { 
        case WM_RBUTTONDOWN:
            colNew            = RGB(255,255,255);
            colOld            = RGB(0,0,0);
            hbm =  ChangePixels(hbm,colOld,colNew,NULL);
            InvalidateRect(hwnd, NULL, TRUE); 
            return 0;
        case WM_CREATE : 
            hbm = getFromInternet("http://www.imperialconflict.com/images/Galaxies/Capricorn.overview.jpg");
            return 0 ; 
        case WM_PAINT: 
            hdc = BeginPaint(hwnd, &ps); 
            GetClientRect(hwnd,&MainRc);
            hMemDC =  CreateCompatibleDC(hdc);
            SelectObject(hMemDC,hbm);
            GetObject(hbm,sizeof(BITMAP),&bm);
            pt.x = MainRc.right;
            pt.y = MainRc.bottom;
            SetStretchBltMode(hdc,COLORONCOLOR);
            StretchBlt(hdc,0,0,pt.x,pt.y,hMemDC,0,0,800,600,SRCCOPY);
            DeleteDC(hMemDC);
            EndPaint(hwnd, &ps);     
            return 0 ; 
        case WM_DESTROY : 
            PostQuitMessage (0) ; 
            return 0 ; 
    } 
    return DefWindowProc (hwnd, iMsg, wParam, lParam) ; 
}