I want to be able to display a captured frame from my webcam using the vfw.h library. I have code which captures a single frame and saves it to a Bitmap file. However, I do not know how to then display this Bitmap file within a window. I only know how to display the live video feed within a window. Apologies in advance for the likely obviousness of this question but I have very little experience in this type of programming. Can anyone advise me on how to display the captured frame in another window, for further manipulation, i.e. examples of how to use the relevant macros? I am using C++ in Visual Studio.
ShowWindow(camhwnd,SW_SHOW);
SendMessage(camhwnd,WM_CAP_DRIVER_CONNECT,0,0);
SendMessage(camhwnd, WM_CAP_SET_SCALE, true , 0);
SendMessage(camhwnd, WM_CAP_SET_PREVIEWRATE, 66, 0);
SendMessage(camhwnd, WM_CAP_SET_PREVIEW, true , 0);
SendMessage(camhwnd, WM_CAP_GRAB_FRAME, 0, 0);
//Grab a Frame
SendMessage(camhwnd, WM_CAP_GRAB_FRAME, 0, 0);
//Copy the frame we have just grabbed to the clipboard
SendMessage(camhwnd, WM_CAP_EDIT_COPY,0,0);
//Copy the clipboard image data to a HBITMAP object called hbm
hdc = BeginPaint(camhwnd, &ps);
hdcMem = CreateCompatibleDC(hdc);
if (hdcMem != NULL)
{
if (OpenClipboard(camhwnd))
{
hbm = (HBITMAP) GetClipboardData(CF_BITMAP);
SelectObject(hdcMem, hbm);
GetClientRect(camhwnd, &rc);
CloseClipboard();
}
}
//Save hbm to a .bmp file called Frame.bmp
PBITMAPINFO pbi = CreateBitmapInfoStruct(hwnd, hbm);
CreateBMPFile(hwnd, "Frame.bmp", pbi, hbm, hdcMem);
SendMessage(camhwnd,WM_CAP_DRIVER_CONNECT,0,0);
SendMessage(camhwnd, WM_CAP_SET_SCALE, true , 0);
SendMessage(camhwnd, WM_CAP_SET_PREVIEWRATE, 66, 0);
SendMessage(camhwnd, WM_CAP_SET_PREVIEW, true , 0);
break;
}
}
break;
}
To display a bitmap, you first create a "handled" bitmap object, which results in your holding HBITMAP value which APIs accept for further manipulations, and then you actually display it.
The first step is achieved using CreateBitmap and friends.
On the second, see Displaying HBITMAP.
Related
I have an MFC desktop application that generates a graphics image, and I want the user to be able to copy it to the clipboard as a bitmap. I use standard clipboard API routines and they have been working fine up to now. However, I have now activated GDI Scaling (via a manifest) so that the program can run (reasonably well) on HiDPI displays, and I find that the image placed on the clipboard is just the upper-left quadrant of the actual image.
This is presumably due to the internal scaling of the image - the display is running at 200%.
How do I copy the whole image?
The key is given in the answer to a previous question:
Saving Bitmaps on Windows 10 with GDI scaling active
but it took me some time to adapt that answer to my particular problem, so I thought I'd share in case it was helpful to others. (Disclaimer - I'm no expert, so there may be better ways...)
bool CopyRectToClipboard(CWnd *pW, CRect rctCopy)
{
if (!pW->OpenClipboard())
return false;
if (!EmptyClipboard())
return false;
CClientDC dc(pW);
CDC dcMem;
VERIFY(dcMem.CreateCompatibleDC(&dc));
CBitmap bmTrial; // need a trial bitmap to get GDI Scaled size
VERIFY(bmTrial.CreateCompatibleBitmap(&dc, rctCopy.Width(), rctCopy.Height()));
// see https://stackoverflow.com/questions/51169846/saving-bitmaps-on-windows-10-with-gdi-scaling-active
BITMAPINFO bi = {};
bi.bmiHeader.biSize = sizeof(bi);
int result = GetDIBits(dc.GetSafeHdc(), (HBITMAP)bmTrial.GetSafeHandle(), 0, 0, NULL, &bi, DIB_RGB_COLORS);
CBitmap bm;
VERIFY(bm.CreateCompatibleBitmap(&dc, bi.bmiHeader.biWidth, bi.bmiHeader.biHeight));
ASSERT(bm.m_hObject != NULL);
CBitmap* pbmOld = dcMem.SelectObject(&bm);
//dcMem.PatBlt(0, 0, bi.bmiHeader.biWidth, bi.bmiHeader.biHeight, WHITENESS); // legacy
VERIFY(dcMem.BitBlt(0, 0, bi.bmiHeader.biWidth, bi.bmiHeader.biHeight,
&dc, rctCopy.left - 1, rctCopy.top - 1, SRCCOPY));
HGDIOBJ hBM = bm.Detach();
VERIFY(::EmptyClipboard());
VERIFY(::SetClipboardData(CF_BITMAP, hBM));
VERIFY(::CloseClipboard());
dcMem.SelectObject(pbmOld);
dcMem.DeleteDC();
return true;
}
I have inherited an old-school MFC Windows CE program, and am having to make some modifications to it. As part of this I have to create a monochrome image with text on it, and both display it on a screen as well as send each row of the image to a printer one at a time.
I originally used a bitmap, and had success using DrawText() and getting a test string (Hello World) to display on the screen (this code is in Figure 1). However, I hit a wall at the stage where I am looking to extract the wrap data from the bitmap. What I am trying to get is an array with 1s or 0s representing black or white. I had first thought I would use GetBitmapBits() but unfortunately the code I am working with is so old that function is not supported yet. I thought I could get around this issue by using GetBitmap() and then accessing the bmBits parameter. However this appears to always be null which was confirmed when I found the following link: Why does GetObject return an BITMAP with null bmBits?.
My next attempt was to follow the advice in the link and use CreateDIBSection() instead of CreateCompatibleBitmap(). This seems like the right path, and I should have access to the data I want, but unfortunately I cannot get the DIB to display (code is in Figure 2). I suspect I am doing something wrong in creating the header of the DIB, but I cannot figure out what my mistake is.
If anyone has suggestions for a way to access the data in the bitmap, or can see what I am doing wrong with the DIB, I would greatly appreciate the help!
*** FIGURE 1: Code to create and display a bitmap
void CRunPage::OnPaint()
{
CPaintDC dc(this); // property page device context for painting
CBitmap mBmp; // CBitmap object for displaying built-in bitmaps
CDC mDCMem; // CDC object to handle built-in bitmap
int iWidth, iHeight; // dimension to draw on the screen
int icurLabel, // current label index of open print file
iLabelNum; // number of labels in open print file
LPBITMAPINFOHEADER pBMIH; // bitmap header object for current label
LPBYTE pImage; // bitmap data for current label
CSize size; // size of label
int PreviewLeft,PreviewTop,PreviewWidth,PreviewHeight;
CRect Rect;
BITMAP bm;
LPVOID bmBits=NULL;
// Calculate the preview area
PreviewLeft=5;
PreviewTop=5;
GetDlgItem(IDC_RUN_NEXT)->GetWindowRect(&Rect);
ScreenToClient(&Rect);
PreviewWidth=Rect.left-PreviewLeft*2;
GetDlgItem(IDC_RUN_WRAPTEXT)->GetWindowRect(&Rect);
ScreenToClient(&Rect);
PreviewHeight=Rect.top-PreviewTop*2;
CRect textRect;
CString testText(_T("Hello World"));
CBitmap * pOldBitmap;
CBrush whiteBrush, *pOldBrush;
CPen blackPen, *pOldPen;
mDCMem.CreateCompatibleDC(&dc);
mBmp.CreateCompatibleBitmap(&dc, PreviewWidth+PreviewLeft*2, PreviewHeight+PreviewTop*2);
//mBmp.CreateCompatibleBitmap(&dc, PreviewWidth, PreviewHeight);
pOldBitmap = mDCMem.SelectObject(&mBmp);
blackPen.CreatePen(PS_SOLID, 2, RGB(0, 0, 0));
whiteBrush.CreateSolidBrush(RGB(255,255,255));
textRect.SetRect(0,0,PreviewWidth, PreviewHeight);
// this means behind the text will be a white box w/ a black boarder
pOldBrush = mDCMem.SelectObject(&whiteBrush);
pOldPen = mDCMem.SelectObject(&blackPen);
//these commands draw on the memory-only context (mDCMem)
mDCMem.Rectangle(&textRect);
mDCMem.DrawText((LPCTSTR)testText, 11, &textRect, DT_CENTER|DT_VCENTER);
mDCMem.SelectObject(pOldBrush);
mDCMem.SelectObject(pOldPen);
dc.StretchBlt(PreviewLeft,PreviewTop, PreviewWidth, PreviewHeight, & mDCMem, 0, 0, PreviewWidth, PreviewHeight, SRCCOPY);
mDCMem.SelectObject(pOldBitmap);
}
*** FIGURE 2: Trying to use a DIB instead of a bitmap
void CRunPage::OnPaint()
{
CPaintDC dc(this); // property page device context for painting
CBitmap mBmp; // CBitmap object for displaying built-in bitmaps
CDC mDCMem; // CDC object to handle built-in bitmap
int iWidth, iHeight; // dimension to draw on the screen
int icurLabel, // current label index of open print file
iLabelNum; // number of labels in open print file
LPBITMAPINFOHEADER pBMIH; // bitmap header object for current label
LPBYTE pImage; // bitmap data for current label
CSize size; // size of label
int PreviewLeft,PreviewTop,PreviewWidth,PreviewHeight;
CRect Rect;
BITMAP bm;
// Calculate the preview area
PreviewLeft=5;
PreviewTop=5;
GetDlgItem(IDC_RUN_NEXT)->GetWindowRect(&Rect);
ScreenToClient(&Rect);
PreviewWidth=Rect.left-PreviewLeft*2;
GetDlgItem(IDC_RUN_WRAPTEXT)->GetWindowRect(&Rect);
ScreenToClient(&Rect);
PreviewHeight=Rect.top-PreviewTop*2;
CRect textRect;
CString testText(_T("Hello World"));
CBitmap * pOldBitmap;
CBrush whiteBrush, *pOldBrush;
CPen blackPen, *pOldPen;
LPBYTE pFWandImageMem=NULL, pImageMem=NULL, pTemp=NULL;
int i=0,j=0, buffSize=0, numBytesPerRow=0, bitmapWidthPix,bitmapHeightPix;
char *numBytesPerRowString;
char temp;
void ** ppvBits;
BITMAPINFOHEADER bmif;
BITMAPINFO bmi;
HBITMAP myDIB, myOldDIB;
mDCMem.CreateCompatibleDC(&dc);
//this rect is the area in which I can draw (its x,y location is set by BitBlt or StretchBlt
//mBmp.CreateCompatibleBitmap(&dc, PreviewWidth+PreviewLeft*2, PreviewHeight+PreviewTop*2);
bmif.biSize = sizeof(BITMAPINFOHEADER);
bmif.biWidth = PreviewWidth+PreviewLeft*2;
bmif.biHeight = -(PreviewHeight+PreviewTop*2);//- means top down (I think? I tried both ways and neither worked)
bmif.biPlanes = 1;
bmif.biBitCount = 1;
bmif.biCompression = BI_RGB; // no compression
bmif.biSizeImage = 0; // Size (bytes) if image - this can be set to 0 for uncompressed images
bmif.biXPelsPerMeter = 0;
bmif.biYPelsPerMeter = 0;
bmif.biClrUsed =0;
bmif.biClrImportant = 0;
bmi.bmiColors[0].rgbBlue=0;
bmi.bmiColors[0].rgbGreen=0;
bmi.bmiColors[0].rgbRed=0;
bmi.bmiColors[0].rgbReserved=0;
bmi.bmiColors[1].rgbBlue=255;
bmi.bmiColors[1].rgbGreen=255;
bmi.bmiColors[1].rgbRed=255;
bmi.bmiColors[1].rgbReserved=0;
bmi.bmiHeader=bmif;
myDIB = CreateDIBSection(dc.GetSafeHdc(), &bmi, DIB_RGB_COLORS, ppvBits, NULL, 0);
myOldDIB = (HBITMAP)mDCMem.SelectObject(myDIB);//SelectObject(mDCMem, myDIB);
blackPen.CreatePen(PS_SOLID, 2, RGB(0, 0, 0));
whiteBrush.CreateSolidBrush(RGB(255,255,255));
textRect.SetRect(0,0,PreviewWidth, PreviewHeight);
// this means behind the text will be a white box w/ a black boarder
pOldBrush = mDCMem.SelectObject(&whiteBrush);
pOldPen = mDCMem.SelectObject(&blackPen);
//these commands draw on the memory-only context (mDCMem)
mDCMem.Rectangle(&textRect);
mDCMem.DrawText((LPCTSTR)testText, 11, &textRect, DT_CENTER|DT_VCENTER);
mDCMem.SelectObject(pOldBrush);
mDCMem.SelectObject(pOldPen);
dc.StretchBlt(PreviewLeft,PreviewTop, PreviewWidth, PreviewHeight, & mDCMem, 0, 0, PreviewWidth, PreviewHeight, SRCCOPY);
mDCMem.SelectObject(myOldDIB);
}
So I made two minor changes to the DIB code, and it is displaying the image correctly now.
First, I changed the way I passed in my pointer to the CreateDIBSection():
void ** ppvBits;
to
LPBYTE pBits;
And then I had to change how I passed that into CreateDIBSection. I also explicitly casted the return of CreateDIBSection() to an HBITMAP:
myDIB = CreateDIBSection(dc.GetSafeHdc(), &bmi, DIB_RGB_COLORS, (void**)&pBits, NULL, 0);
to
myDIB = (HBITMAP) CreateDIBSection(dc.GetSafeHdc(), &bmi, DIB_RGB_COLORS, ppvBits, NULL, 0);
I have not had a chance to see if I can access the image data, but I am past the initial issues now. Thanks to anyone who looked at this, and if people know how to do the first (device dependent bitmap) method I would be interested to know.
Is it right to create two bitmaps for one DC?
My situation is I have
dc = CreateCompatibleDC(NULL);
bitmap = CreateDIBSection(dc, pbmi1, DIB_RGB_COLORS, (void **) &bmpBits, NULL, 0);
extra_bitmap = CreateDIBSection(dc, pbmi2, DIB_RGB_COLORS, (void **) &extraBmpBits, NULL, 0);
The difference is: bitmap is width*height , extra_bitmap is width/2*height*2
I need to show both images on the screen according to requirements from users.
I tried these code above, it can run (based only on my limited test). But I am not sure if it is the right way to do it. Any suggestions and/or comments are welcome. Thanks.
By the way, if I can have two bitmaps associated with one DC, what is the right way to release them? Can I just call DeleteDC(dc)? Thanks.
Bitmaps are only associated with a DC when they're selected into them via SelectObject. The DC you pass to the CreateDIBSection is only used to define the layout/palette of the newly created bitmap, and only in some circumstances, but it doesn't irrevocably associate that bitmap with the DC or anything like that.
To draw a bitmap to a window, it needs to be selected into a DC (the "source DC"), and this is where you can only have one at a time.
For example:
HDC hdcTarget = GetDC(hWnd); // or hdcTarget = BeginPaint(...)
HDC hdcSource = CreateCompatibleDC(hdcTarget); // create a "source DC")
HGDIOBJ hOldBmp = SelectObject(dc, bitmap); // select bitmap 1 in
BitBlt(hdcTarget, x, y, w, h, hdcSource, 0, 0, SRCCOPY); // draw bitmap 1
SelectObject(hdcSource, extra_bitmap); // select bitmap 2 in
BitBlt(hdcTarget, x1, y1, w1, h1, hdcSource, 0, 0, SRCCOPY); // draw bitmap 2
SelectObject(hdcSource, hOldBmp); // restore previous bitmap
DeleteDC(hdcSource); // no longer needed
ReleaseDC(hWnd, hdcTarget); // or EndPaint(...)
After search around for a few hours, I get
http://www.ucancode.net/Visual_C_MFC_Samples/CreateDIBSection-BITMAPINFOHEADER-CreateCompatibleDC-BITMAPINFO.htm
In this example:
// Create HDCs to hold our surfaces.
hdcSrc1 = CreateCompatibleDC(hdcDest);
if (!hdcSrc1) goto HANDLEERROR;
hdcSrc2 = CreateCompatibleDC(hdcDest);
if (!hdcSrc2) goto HANDLEERROR;
For delete:
DeleteDC(hdcSrc1);
DeleteDC(hdcSrc2);
DeleteObject(hbmSrc1); // hbmSrc1 and hbmSrc2 are created using hbm = CreateDIBSection(hDC, &bmi, DIB_RGB_COLORS,(void **)&pBits, NULL, 0);
DeleteObject(hbmSrc2);
Hope this can be helpful for others. thanks.
You may create as many in-memory bitmaps as you like.
You may create as many device-dependent DCs as you like.
A bitmap may be selected into only one DC at a time. If you try to select the same bitmap into multiple DCs, then you will get unpredictable behavior.
A DC will never have more that one bitmap selected into it at a time, because the act of selecting one in selects the previous one out.
Don't delete a memory DC while your bitmap is still selected into it. You should select the original bitmap (which is a monochrome 1x1 bitmap) into the DC to get your bitmap out before you delete the DC.
Don't delete an in-memory bitmap while it's still selected into a DC.
was using XP without issue for a long time. switched to 7 and trying to capture screenshots with my previously functioning code no longer works. simple concept and relatively generic code...just find the window that i call and save it as a .png. any ideas what might make this bad boy run again? can't debug with my current setup, but it makes it all the way and spits out the error message after bmp->save(...) ...couldn't save image file. edit: also a file does get created/saved, but it is blank and not written to. perhaps the bitmap encoding or GDI is screwed up?
bool CScreenShot::Snap(CString wintitle, CString file, CString& ermsg)
{
ermsg = ""; // no error message
// create screen shot bitmap
EnumWinProcStruct prm = {0, (LPSTR)(LPCTSTR)wintitle, 0};
// Find the descriptor of the window with the caption wintitle
EnumDesktopWindows(0, EnumWindowsProc, (LPARAM)&prm);
if(!prm.hwnd)
{
ermsg.Format("couldn't find window \"%s\"", wintitle);
return false;
}
// Make the window the topmost window
SetWindowPos(prm.hwnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE);
Sleep(300);
// Get device context for the top-level window and client rect
HDC hDC = GetDC(prm.hwnd);
RECT rc;
GetClientRect(prm.hwnd, &rc);
HDC memDC = CreateCompatibleDC(hDC);
// Set the size and color depth for the screen shot image
BITMAPINFO bmpInfo;
memset(&bmpInfo, 0, sizeof(bmpInfo));
bmpInfo.bmiHeader.biSize = sizeof(bmpInfo.bmiHeader);
bmpInfo.bmiHeader.biWidth = rc.right - rc.left;
bmpInfo.bmiHeader.biHeight = rc.bottom - rc.top;
bmpInfo.bmiHeader.biPlanes = 1;
bmpInfo.bmiHeader.biBitCount = 24;
bmpInfo.bmiHeader.biCompression = BI_RGB;
bmpInfo.bmiHeader.biSizeImage = bmpInfo.bmiHeader.biWidth * bmpInfo.bmiHeader.biHeight * 3;
// Create memory buffer and perform a bit-block transfer of the color data from the window to the memory
LPVOID addr;
HBITMAP memBM = CreateDIBSection(memDC, &bmpInfo, DIB_RGB_COLORS, &addr, 0, 0);
HGDIOBJ stdBM = SelectObject(memDC, memBM);
BOOL OK = BitBlt(memDC, 0, 0, bmpInfo.bmiHeader.biWidth, bmpInfo.bmiHeader.biHeight, hDC, 0, 0, SRCCOPY);
ReleaseDC(prm.hwnd, hDC);
SetWindowPos(prm.hwnd, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE);
// Initialize GDI+.
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
if(GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL) != Ok)
{
ermsg.Format("couldn't start GDI+");
return false;
}
// Create a Bitmap object for work with images defined by pixel data from the GDI HBitmap and the GDI HPalette.
Bitmap* bmp = ::new Bitmap(memBM, DIB_RGB_COLORS);
SelectObject(memDC, stdBM);
DeleteObject(memBM);
DeleteDC(memDC);
// Find the encoder for "image/png" mime type
CLSID encoderClsid;
EncoderParameters encoderParameters;
GetEncoderClsid(L"image/png", &encoderClsid);
encoderParameters.Count = 0;
// Convert file name to Unicode (wide-char) string.
WCHAR fn[_MAX_PATH];
MultiByteToWideChar(CP_THREAD_ACP, MB_PRECOMPOSED, file, file.GetLength() + 1, fn, _MAX_PATH);
// Save the screen shot into the specified file using image encoder with the mime style "image/png"
if(bmp->Save(fn, &encoderClsid, &encoderParameters) != Ok)
{
ermsg.Format("couldn't save image file \"%s\"", file);
return false;
}
::delete bmp;
GdiplusShutdown(gdiplusToken);
return true;
}
The error message implies that you're trying to save the file to a folder that you don't have permission to write to. Many folders such as Program Files are now protected. Since you didn't include the path in your sample code I'm unable to determine if this is the actual problem.
Edit: Another possibility is that the Bitmap is improperly constructed which causes the Save to fail. The second parameter to the constructor is supposed to be a handle to a palette, I think DIB_RGB_COLORS would be invalid here and you should use NULL. Also there are a couple of caveats noted in the Microsoft documentation and perhaps the different OS versions react differently when you break the rules:
You are responsible for deleting the GDI bitmap and the GDI palette. However, you should not delete the GDI bitmap or the GDI palette until after the GDI+ Bitmap::Bitmap object is deleted or goes out of scope.
Do not pass to the GDI+ Bitmap::Bitmap constructor a GDI bitmap or a GDI palette that is currently (or was previously) selected into a device context.
win7 won't accept encoderParameters.Count == 0 for some reason. Set that == 1 and you should be all set.
you probably could also just remove that parameter from Save() (overloaded)
I want to load a BitMap image in a pic box I created inside a window...picBoxDisp is created using following mechanism..
picBoxDisp = CreateWindow("STATIC", "image box",
WS_VISIBLE |WS_CHILD | SS_BITMAP |WS_TABSTOP | WS_BORDER,
50, 50, 250, 300, hwnd , (HMENU)10000, NULL, NULL);
Now Next I created a hBitmap object and loaded an image in to it...
hBitmap = (HBITMAP) LoadImage(NULL,szFileName,IMAGE_BITMAP,0,0,
LR_LOADFROMFILE| LR_DEFAULTSIZE);
SendMessage(picBoxDisp,STM_SETIMAGE,(WPARAM) IMAGE_BITMAP,(LPARAM) NULL);
//now assign the new image
//Create a compatible DC for the original size bitmap, for example originalMemDc.
HDC originalDC = GetDC((HWND)hBitmap);
HDC originalMemDC = CreateCompatibleDC(originalDC);
if(originalMemDC==NULL){
MessageBox(NULL,"Problem while creating DC.","Error",MB_OK);
}
//Select hBitmap into originalMemDc.
SelectObject(originalMemDC,hBitmap);
//Create a compatible DC for the resized bitmap, for example resizedMemDc.
HDC picBoxDC = GetDC(picBoxDisp);
HDC resizedMemDC = CreateCompatibleDC(picBoxDC);
//Create a compatible bitmap of the wanted size for the resized bitmap,
HBITMAP hResizedBitmap = CreateCompatibleBitmap(picBoxDC,250,300);
//Select hResizedBitmap into resizedMemDc.
SelectObject(resizedMemDC,hResizedBitmap);
//Stretch-blit from originalMemDc to resizedMemDc.
//BitBlt(resizedMemDC,0,0,250,300,originalMemDC,0,0,SRCCOPY);
BITMAP bmp_old,bmp_new;
GetObject(hBitmap,sizeof(bmp_old),&bmp_old);
GetObject(hResizedBitmap,sizeof(bmp_new),&bmp_new);
StretchBlt ( resizedMemDC,0,0,bmp_new.bmWidth,bmp_new.bmHeight,
originalMemDC,0,0,bmp_old.bmWidth,bmp_new.bmHeight,
SRCCOPY);
////De-select the bitmaps.
if((resizedMemDC==NULL)||(hResizedBitmap == NULL)) {
MessageBox(NULL,"Something is NULL","Error",MB_OK);
}
else
//Set hResizedBitmap as the label image with STM_SETIMAGE
SendMessage(picBoxDisp,STM_SETIMAGE, (WPARAM) IMAGE_BITMAP,(LPARAM) hResizedBitmap);
I just cant understand, why the above code is not working ?
Thanks in advance,
You misunderstood the STM_SETIMAGE usage. Do this:
hBitmap = (HBITMAP)::LoadImage(NULL, szFileName, IMAGE_BITMAP,
0, 0, LR_LOADFROMFILE| LR_DEFAULTSIZE);
if (hBitmap != NULL)
{
::SendMessage(picBoxDisp, STM_SETIMAGE,
(WPARAM)IMAGE_BITMAP, (LPARAM)hBitmap);
}
EDIT: If you want to resize the bitmap before setting it as the label image, then follow this scheme for the simplest possible way to do it (with sub-optimal quality in the resized image...):
Create a compatible DC for the original size bitmap, for example originalMemDc.
Select hBitmap into originalMemDc.
Create a compatible DC for the resized bitmap, for example resizedMemDc.
Create a compatible bitmap of the wanted size for the resized bitmap, for example hResizedBitmap.
Select hResizedBitmap into resizedMemDc.
Stretch-blit from originalMemDc to resizedMemDc.
De-select the bitmaps.
Set hResizedBitmap as the label image with STM_SETIMAGE
Should work!
The static control won't stretch the image to its size. You could use SS_CENTERIMAGE but it either clips or fills the empty space with the color of the top left pixel (see http://msdn.microsoft.com/en-US/library/b7w5x74z.aspx). You'd have to stretch the bitmap yourself before sending it to the static control.
You're trying to assign an image to a static control, so you don't need to draw the image but to set the image on it.
// set the image
HBITMAP hold = (HBITMAP)SendMessage(hpicBoxDc, STM_SETIMAGE, IMAGE_BITMAP, LPARAM(hBitmap));
// clear the old image
if(hold && hold != hBitmap)
DeleteObject(hold );