Thread: Loading and Displaying Other Format Images (than bmp)

GDI+ can open, png, gif, jpeg, tiff and some other...
or..try CImage

Something like....

Free any current image.

Use OLELoadPicture() to load the .jpg

Create a memory DC and bitmap (using the screen and the image size as params)

Use the LPPICTURE Render() method to copy the jpg image to the memory DC's bitmap.

Release the LPPICTURE.

Use the memory DC to draw the image as required
OR
SelectObject() the default BMP back into the memory DC and free the memory DC (saving the image in the HBITMAP object).

Clean up the memory DC when the app closes.

Example code: http://www.codeproject.com/KB/graphics/render.aspx

You can call your resources almost anything you like (unless it collides with some name the IDE is using, which should generate an error).

Only a quick look....

By default the created DC contains a 1x1 black and white bitmap (which will not hold much of your image). You need a new BMP the same size as the client area.

CreateCompatibleBitmap() [using hMem and the client area] and SelectObject() [catching the returned default HBITMAP] this HBITMAP into the hMem DC.

Call Render() to draw on the new HBITMAP.

Clean up by SelectObject() the default HBITMAP back into the hMem DC (which will 'push' out the created one you want to return) before using DeleteDC() the hMem DC.

Code:

//is this a typo in your code as well? (because these resource names don't match) 
#define JPG_BACKGROUND 50000
JPG_BACKGROUND0       

//this is a GDI memory leak
HDC hMem = CreateCompatibleDC(GetDC(hwnd)); 

You should ReleaseDC() and DC you 'get' (and delete any you 'create').

Narrow down where the error occurs by adding msgs to tell you/me what error occurred (not just that an error occurred).

Use breakpoints and GetLastError() to diagnose the problem.

Thanks again for the reply.

Alright, it looks better now, and I checked quite a few of the return values, and everything looks good... but when the background is displayed its completely red, and turns white after about a minute. I don't know what that is about since the bitmap is loaded once and doesn't change.

The one thing I know isn't right is the width and height, but the ratio looks correct... so I think theres a conversion I need for that. I think I still might be using Render wrong though, because the example I looked at has it setup like:

Code:

gpPicture->Render(pDC->m_hDC,
                          ptUL.x,
                          ptUL.y,
                          nWidth,
                          -nHeight,
                          0,
                          hmHeight,
                          hmWidth,
                          -hmHeight,
                          &rc);

The &rc can be NULL, but they use odd positioning, and the - before height doesn't even seem valid.

I looked at msdn and mine looks correct...

any idea, or as to what I should debug further?

Code:

HBITMAP loadResourcePicture(int resid) {
    
    // variables
    HBITMAP hBitmap;
    HBITMAP hDefaultBmp;
    DWORD dwFileSize;
    LPPICTURE gpPicture;
    LPVOID lpPicData;
    LPVOID pvData;
    LPSTREAM pstm;
    HRSRC hrlp;
    HGLOBAL hGlobal;
    HDC hdc;
    HDC hMem;
    HINSTANCE hInst = (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE);
    long width;
    long height;
    
    // find resource
    hrlp = FindResource(hInst, MAKEINTRESOURCE(resid), RT_RCDATA);
    
    // make sure it found something
    if (hrlp != NULL) {
        dwFileSize = SizeofResource(hInst, hrlp);
        hGlobal = LoadResource(hInst, hrlp);
        
        // something was loaded
        if (hGlobal != 0) {
            lpPicData = LockResource(hGlobal);
            pvData = NULL;
            hGlobal = GlobalAlloc(GMEM_MOVEABLE, dwFileSize);
            pvData = GlobalLock(hGlobal);
            CopyMemory(pvData, lpPicData, dwFileSize);
            GlobalUnlock(hGlobal);
            
            // create stream and load picture from it
            CreateStreamOnHGlobal(hGlobal, TRUE, &pstm); // returns s_ok
            OleLoadPicture(pstm, 0, FALSE, IID_IPicture, (LPVOID*)&gpPicture); // returns s_ok
            pstm->Release();
            
            // get picture
            hdc = GetDC(hwnd);
            hMem = CreateCompatibleDC(hdc);
            gpPicture->get_Width(&width); // returns around 40000 compared to 1500
            gpPicture->get_Height(&height); // returns around 12000 compared to 464
            width = 1500;
            height = 464;
            gpPicture->Render(hMem, 0, 0, width, height, 0, height, width, -1*height, NULL); // returns s_ok
            //hBitmap = CreateCompatibleBitmap(hMem, width, height);
            hDefaultBmp = CreateCompatibleBitmap(hMem, width, height);
            hBitmap = (HBITMAP)SelectObject(hMem, hDefaultBmp); // for now
            //hBitmap = (HBITMAP)GetCurrentObject(hMem, OBJ_BITMAP);  
            ReleaseDC(hwnd, hdc);
            
            // release picture
            gpPicture->Release();
            
            // delete dcs
            DeleteDC(hdc);
            DeleteDC(hMem);
            
            // return
            return hBitmap;
        }

    }
    
    MessageBox(hwnd, "Fail", NULL, MB_OK);
}

EDIT: Render should be fixed, and still nothing. I drew a rectangle to hMem right after the render, and still nothing. So I am guessing the HBITMAP is not being returned correctly...

In the example they are trying to center the image (by modifing the starting positions).


You are not creating the bitmap at the right time.

Code:

// get picture
hdc = GetDC(hwnd);
hMem = CreateCompatibleDC(hdc);

//get the size of the client area
rect rcClient = {0};
GetClientRect(hwnd, &rcClient);
int ClientWidth = rcClient.right-rcClient.left;
 int ClientHeight = rcClient.bottom-rcClient.top;
//create our bitmap
hBitmap = CreateCompatibleBitmap(hMem, ClientWidth, ClientHeight);   
//select the bitmap into the DC      
hDefaultBmp = (HBITMAP)SelectObject(hMem, hBitmap ); 

//find the image size
gpPicture->get_Width(&width); 
gpPicture->get_Height(&height); 

//render to our BMP
gpPicture->Render(hMem, 0, 0, ClientWidth, ClientHeight , 0, 0, width, height, NULL);//or &rcClient 

//clean up

SelectObject(hMem, hDefaultBmp); // put the created mem DC back to default before deleteing it  (and 'push out' our HBITMAP)        

ReleaseDC(hwnd, hdc); //do not DeleteDC this as well
            
// release picture
gpPicture->Release();
DeleteDC(hMem);           
                  
 // return
 return hBitmap;

If you want to convert from HIMETRIC to pixels (and not use the client rect area).

Code:

gpPicture->get_Width(&hmWidth); 
gpPicture->get_Height(&hmHeight); 

// convert himetric to pixels 
int nWidth = MulDiv(hmWidth, GetDeviceCaps(hdc, LOGPIXELSX), HIMETRIC_INCH); 
int nHeight = MulDiv(hmHeight, GetDeviceCaps(hdc, LOGPIXELSY), HIMETRIC_INCH);

EDIT:
As a HBITAMP is a void* you should be able to return a local pointer (and not create a dangling pointer).

You can check the image with

Code:

BITMAP bmp={0};
GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&bmp);

//what are the dimensions (bmp.bmWidth etc), are they the expected size?

Also if you are only loading one image in the life of the app you could return the HDC (declare it with enough scope ie global to the window).

Then use the HDC to BitBlt() the image to the screen in your WM_PAINT (ie BitBlt() to the HDC in the PAINTSTRUCT using the rect in the PAINTSTRUCT )

NOTE: not complied let alone tested (just off the top of my head...)

Wow, thanks a lot for the replies. I was really doubting this would work, but with the change above it is now working as it should:

Code:

HBITMAP loadResourcePicture(int resid) {
    
    // variables
    HBITMAP hBitmap;
    DWORD dwFileSize;
    LPPICTURE gpPicture;
    LPVOID lpPicData;
    LPVOID pvData;
    LPSTREAM pstm;
    HRSRC hrlp;
    HGLOBAL hGlobal;
    //HDC hdc;
    //HDC hMem;
    HINSTANCE hInst = (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE);
    long width;
    long height;
    
    // find resource
    hrlp = FindResource(hInst, MAKEINTRESOURCE(resid), RT_RCDATA);
    
    // make sure it found something
    if (hrlp != NULL) {
        dwFileSize = SizeofResource(hInst, hrlp);
        hGlobal = LoadResource(hInst, hrlp);
        
        // something was loaded
        if (hGlobal != 0) {
            lpPicData = LockResource(hGlobal);
            pvData = NULL;
            hGlobal = GlobalAlloc(GMEM_MOVEABLE, dwFileSize);
            pvData = GlobalLock(hGlobal);
            CopyMemory(pvData, lpPicData, dwFileSize);
            GlobalUnlock(hGlobal);
            
            // create stream and load picture from it
            CreateStreamOnHGlobal(hGlobal, TRUE, &pstm); // returns s_ok
            
            // keep everything above here
            OleLoadPicture(pstm, 0, TRUE, IID_IPicture, (LPVOID*)&gpPicture); // returns s_ok
            HBITMAP hBmCur = NULL;
            gpPicture->get_Handle((OLE_HANDLE*)&hBmCur);
            hBitmap = (HBITMAP)CopyImage((HBITMAP)hBmCur, IMAGE_BITMAP, 0, 0, 0);
            gpPicture->Release();
            return hBitmap;

        }

    }
    
    MessageBox(hwnd, "Failed Loading Picture", NULL, MB_OK);
}

could use more error checking, but it works fine.

Found another problem, commented out the unused HDCs, which should have been gone anyways, but ended up causing a problem with other bitmaps loading with the LoadImage() function started to load improperly, and caused things associated with the bitmaps to act really weird.

Originally Posted by adeyblue

You can do it with faffing with HDC's:

I always just leave the image in a HDC for as long as I need it.

Originally Posted by Brokenhope

Code:

DeleteDC(hMem); //you just deleted the HDC containing the hBitmap (and so probably deleted hBitmap) the delete may fail however, as you have not retunred the HDC to the default state
            
return hBitmap;//this is probably now a dangling pointer

You must also use DeleteObject() on the HBITMAP before loading another.

Originally Posted by Brokenhope

Found another problem, commented out the unused HDCs, which should have been gone anyways, but ended up causing a problem with other bitmaps loading with the LoadImage() function started to load improperly, and caused things associated with the bitmaps to act really weird.

Sounds like a GDI memory leak.