CODEWITHSUNDEEP
winapigdi+clipboard
Ian Boyd
Ian Boyd

Reputation: 256741

How to place GDI+ Bitmap onto the clipboard?

I want to place a GDI+ Bitmap onto the clipboard. The obvious way would be to:

So i try pseudo-code:

void PlaceBitmapOnClipboard(Bitmap image)
{
   //Convert GDI+ Bitmap to GDI Bitmap
   HBITMAP bmp;
   image.GetHBITMAP(0, @bmp);

   OpenClipboard(this.Handle);
      EmptyClipboard();
      SetClipboardData(CF_BITMAP, bmp);
   CloseClipboard();
}

Error checking has been omitted for expository purposes; but neither function fails:

But when i try to use the CF_BITMAP on the clipboard, it can't be pasted into Paint:

enter image description here

So, what is the correct code to fill in the function:

void PlaceBitmapOnClipboard(Bitmap image)
{
   //TODO: Ask Stackoverflow to figure this out

}

Upvotes: 2

Views: 2030

Answers (1)

Barmak Shemirani
Barmak Shemirani

Reputation: 31599

We need to call:
SetClipboardData(CF_BITMAP, hbitmap_ddb)

Where hbitmap_ddb must be a compatible bitmap (DDB), not DIB which we get from Gdiplus::GetHBitmap

Or we call:
SetClipboardData(CF_DIB, hmemory)

Where hmemory is not HBITMAP. hmemory is described in documentation as:

A memory object containing a BITMAPINFO structure followed by the bitmap bits.

Example using CF_BITMAP

Use CreateDIBitmap to create a compatible bitmap based on our DIB bitmap. Then call SetClipboardData with the new DDB bitmap.

Gdiplus::Bitmap gdibmp(L"file.bmp");
if(gdibmp.GetLastStatus() != Gdiplus::Ok)
    return;
HBITMAP hbitmap;
auto status = gdibmp.GetHBITMAP(0, &hbitmap);
if(status != Gdiplus::Ok)
    return;
BITMAP bm;
GetObject(hbitmap, sizeof bm, &bm);
DIBSECTION ds;
if(sizeof ds == GetObject(hbitmap, sizeof ds, &ds))
{
    HDC hdc = GetDC(NULL);
    HBITMAP hbitmap_ddb = CreateDIBitmap(hdc, &ds.dsBmih, CBM_INIT,
        ds.dsBm.bmBits, (BITMAPINFO*)&ds.dsBmih, DIB_RGB_COLORS);
    ReleaseDC(NULL, hdc);
    if(OpenClipboard(hwnd))
    {
        EmptyClipboard();
        SetClipboardData(CF_BITMAP, hbitmap_ddb);
        CloseClipboard();
    }
    DeleteObject(hbitmap_ddb);
}
DeleteObject(hbitmap);

Example using CF_DIB

Use GlobalAlloc to allocate memory, and copy BITMAPINFOHEADER to that memory, followed by the bits. There is no need to worry about the color table, because Gdiplus::HBitmap returns 32-bit bitmap (at least on modern displays as far as I know)

Gdiplus::Bitmap gdibmp(L"file.bmp");
if(gdibmp.GetLastStatus() != Gdiplus::Ok)
    return;

HBITMAP hbitmap;
auto status = gdibmp.GetHBITMAP(NULL, &hbitmap);
if(status != Gdiplus::Ok)
    return;
BITMAP bm;
GetObject(hbitmap, sizeof bm, &bm);

BITMAPINFOHEADER bi =
{ sizeof bi, bm.bmWidth, bm.bmHeight, 1, bm.bmBitsPixel, BI_RGB };

std::vector<BYTE> vec(bm.bmWidthBytes * bm.bmHeight);
auto hdc = GetDC(NULL);
GetDIBits(hdc, hbitmap, 0, bi.biHeight, vec.data(), (BITMAPINFO*)&bi, 0);
ReleaseDC(NULL, hdc);

auto hmem = GlobalAlloc(GMEM_MOVEABLE, sizeof bi + vec.size());
auto buffer = (BYTE*)GlobalLock(hmem);
memcpy(buffer, &bi, sizeof bi);
memcpy(buffer + sizeof bi, vec.data(), vec.size());
GlobalUnlock(hmem);

if(OpenClipboard(hwnd))
{
    EmptyClipboard();
    SetClipboardData(CF_DIB, hmem);
    CloseClipboard();
}
DeleteObject(hbitmap);

Upvotes: 2

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