+static size_t wxGetNumOfBitmapColors(size_t bitsPerPixel)
+{
+ switch ( bitsPerPixel )
+ {
+ case 1:
+ // monochrome bitmap, 2 entries
+ return 2;
+
+ case 4:
+ return 16;
+
+ case 8:
+ return 256;
+
+ case 24:
+ // may be used with 24bit bitmaps, but we don't use it here - fall
+ // through
+
+ case 16:
+ case 32:
+ // bmiColors not used at all with these bitmaps
+ return 0;
+
+ default:
+ wxFAIL_MSG( wxT("unknown bitmap format") );
+ return 0;
+ }
+}
+
+size_t wxConvertBitmapToDIB(LPBITMAPINFO pbi, const wxBitmap& bitmap)
+{
+ wxASSERT_MSG( bitmap.Ok(), wxT("invalid bmp can't be converted to DIB") );
+
+ // shouldn't be selected into a DC or GetDIBits() would fail
+ wxASSERT_MSG( !bitmap.GetSelectedInto(),
+ wxT("can't copy bitmap selected into wxMemoryDC") );
+
+ // prepare all the info we need
+ BITMAP bm;
+ HBITMAP hbmp = (HBITMAP)bitmap.GetHBITMAP();
+ if ( !GetObject(hbmp, sizeof(bm), &bm) )
+ {
+ wxLogLastError(wxT("GetObject(bitmap)"));
+
+ return 0;
+ }
+
+ // calculate the number of bits per pixel and the number of items in
+ // bmiColors array (whose meaning depends on the bitmap format)
+ WORD biBits = bm.bmPlanes * bm.bmBitsPixel;
+ WORD biColors = (WORD)wxGetNumOfBitmapColors(biBits);
+
+ BITMAPINFO bi2;
+
+ bool wantSizeOnly = pbi == NULL;
+ if ( wantSizeOnly )
+ pbi = &bi2;
+
+ // just for convenience
+ BITMAPINFOHEADER& bi = pbi->bmiHeader;
+
+ bi.biSize = sizeof(BITMAPINFOHEADER);
+ bi.biWidth = bm.bmWidth;
+ bi.biHeight = bm.bmHeight;
+ bi.biPlanes = 1;
+ bi.biBitCount = biBits;
+ bi.biCompression = BI_RGB;
+ bi.biSizeImage = 0;
+ bi.biXPelsPerMeter = 0;
+ bi.biYPelsPerMeter = 0;
+ bi.biClrUsed = 0;
+ bi.biClrImportant = 0;
+
+ // memory we need for BITMAPINFO only
+ DWORD dwLen = bi.biSize + biColors * sizeof(RGBQUAD);
+
+ // first get the image size
+ ScreenHDC hdc;
+ if ( !GetDIBits(hdc, hbmp, 0, bi.biHeight, NULL, pbi, DIB_RGB_COLORS) )
+ {
+ wxLogLastError(wxT("GetDIBits(NULL)"));
+
+ return 0;
+ }
+
+ if ( wantSizeOnly )
+ {
+ // size of the header + size of the image
+ return dwLen + bi.biSizeImage;
+ }
+
+ // and now copy the bits
+ void *image = (char *)pbi + dwLen;
+ if ( !GetDIBits(hdc, hbmp, 0, bi.biHeight, image, pbi, DIB_RGB_COLORS) )
+ {
+ wxLogLastError(wxT("GetDIBits"));
+
+ return 0;
+ }
+
+ return dwLen + bi.biSizeImage;
+}
+
+wxBitmap wxConvertDIBToBitmap(const LPBITMAPINFO pbmi)
+{
+ // here we get BITMAPINFO struct followed by the actual bitmap bits and
+ // BITMAPINFO starts with BITMAPINFOHEADER followed by colour info
+ const BITMAPINFOHEADER *pbmih = &pbmi->bmiHeader;
+
+ // biClrUsed has the number of colors, unless it's 0
+ int numColors = pbmih->biClrUsed;
+ if (numColors==0)
+ {
+ numColors = wxGetNumOfBitmapColors(pbmih->biBitCount);
+ }
+
+ // offset of image from the beginning of the header
+ DWORD ofs = numColors * sizeof(RGBQUAD);
+ void *image = (char *)pbmih + sizeof(BITMAPINFOHEADER) + ofs;
+
+ ScreenHDC hdc;
+ HBITMAP hbmp = CreateDIBitmap(hdc, pbmih, CBM_INIT,
+ image, pbmi, DIB_RGB_COLORS);
+ if ( !hbmp )
+ {
+ wxLogLastError(wxT("CreateDIBitmap"));
+ }
+
+ wxBitmap bitmap(pbmih->biWidth, pbmih->biHeight, pbmih->biBitCount);
+ bitmap.SetHBITMAP((WXHBITMAP)hbmp);
+
+ return bitmap;
+}
+
projects / wxWidgets.git / blobdiff