wpSetContentsFromHandle - Example Code

This example shows how the Image File class processes the wpSetContentsFromHandle method. Notice how this method finds the bitmap data from the specified handle and calls the wpSetBitmapData method to update the data file. This allows any subclass of WPImageFile to provide this function without writing any extra code.

SOM_Scope BOOL SOMLINK img_wpSetContentsFromHandle(WPImageFile *somSelf,
                                                   LHANDLE handle)
{
   BITMAPINFOHEADER2    bmih;
   PBITMAPINFO2         pbmih = NULL;
   ULONG                scansize, tsize;
   LONG                 bmisize;
   PVOID                data;
   BOOL                 bResult;
   PBITMAPFILEHEADER2   pbmfh = NULL;
   ULONG                bmfhsize, ctabsize;
   HBITMAP              hbm = handle;
   HDC                  hdc = NULLHANDLE;
   SIZEL                sizl = {0L, 0L};
   HPS                  hps = NULLHANDLE;
   HPAL                 hPalette = NULLHANDLE;

   /* Get the bitmap information header from the bitmap  */
   bmih.cbFix = sizeof(bmih);
   if (!GpiQueryBitmapInfoHeader(hbm, &bmih))
   {
      return(FALSE);
   }

   /* Allocate a buffer large enough to contain the bitmap file header,
    * the bitmap information header, the color table, and the bitmap data */
   scansize = ((bmih.cBitCount*bmih.cx+31)/32)*bmih.cPlanes*4;
   bmisize = (bmih.cbFix+(sizeof(RGB2))*
                 (bmih.cclrUsed ? bmih.cclrUsed :
                                  1<<(bmih.cBitCount*bmih.cPlanes) ) );

   tsize = bmisize + scansize*bmih.cy + offsetof(BITMAPFILEHEADER2, bmp2);

   pbmfh = (PBITMAPFILEHEADER2) AllocMem(tsize, NULL);
   if (!pbmfh)
   {
      return(FALSE);
   }

   /* Copy the bitmap information header to the buffer  */
   pbmih = (PVOID) (((PBYTE)pbmfh) + offsetof(BITMAPFILEHEADER2,bmp2));
   data = (PVOID)pbmih;
   memcpy(data, (PVOID)&bmih, bmih.cbFix);
   pbmih->cBitCount = bmih.cBitCount*bmih.cPlanes;
   pbmih->cPlanes = 1;
   pbmih->cbImage = scansize*bmih.cy;

   /* Open a Device Context for the bitmap  */
   hdc = DevOpenDC (vhab, OD_MEMORY, "*", 0L, NULL, NULLHANDLE);
   if (hdc == DEV_ERROR)
   {
      FreeMem((PCHAR)pbmfh);
      pbmfh = NULL;
      return FALSE;
   }

   /* Create a Presentation Space for the bitmap  */
   hps = GpiCreatePS (vhab,
                      hdc,
                      &sizl,
                      PU_PELS | GPIT_NORMAL | GPIA_ASSOC);
   if (hps == GPI_ERROR)
   {
      DevCloseDC (hdc);
      hdc = NULLHANDLE;
      FreeMem((PCHAR)pbmfh);
      pbmfh = NULL;
      return FALSE;
   }

   /* Copy the color table and bitmap data to the buffer  */
   GpiCreateLogColorTable(hps,0,LCOLF_RGB,0,0,NULL);
   GpiSelectPalette(hps,hPalette);
   GpiSetBitmap(hps,hbm);
   GpiQueryBitmapBits(hps, 0, bmih.cy, ((PSZ)data)+bmisize, pbmih);
   GpiSetBitmap(hps,NULLHANDLE);
   GpiSelectPalette(hps,NULLHANDLE);
   GpiAssociate(hps,NULLHANDLE);
   GpiDestroyPS(hps);
   hps = NULLHANDLE;
   DevCloseDC (hdc);
   hdc = NULLHANDLE;

   ctabsize = ((sizeof(RGB2))* (pbmih->cclrUsed ? pbmih->cclrUsed :
                               1<<(pbmih->cBitCount*pbmih->cPlanes) ) );

   bmfhsize = offsetof(BITMAPFILEHEADER2, bmp2) +
              sizeof(BITMAPINFOHEADER2) +
              ctabsize;

   /* Construct the bitmap file header at the beginning of the buffer  */
   pbmfh->usType   = BFT_BMAP;
   pbmfh->cbSize   = bmfhsize+pbmfh->bmp2.cbImage;
   pbmfh->xHotspot = 0;
   pbmfh->yHotspot = 0;
   pbmfh->offBits  = bmfhsize;

   /* Update the image file from the bitmap data  */
   bResult = _wpSetBitmapData(somSelf,(PBYTE)pbmfh,tsize);

   /* Free the temporary buffer and return to the caller  */
   FreeMem((PCHAR)pbmfh);
   pbmfh = NULL;
   return bResult;
}