LImageViewer::EnableLowMemoryUsageCallBack

#include "ltwrappr.h"

L_BOOL LImageViewer::EnableLowMemoryUsageCallBack(bEnable)

Enables or disables the LImageViewer::LowMemoryUsageCallBack function.

Returns

The previous setting.

Comments

Call this function to enable or disable the Low Memory Usage callback overridable function for your class object. This will enable or disable the callback functions, which exist in the calling object.

Required DLLs and Libraries

See Also

Example

This example shows how to use the low memroy usage feature to display a medical image with multiple pages. it will also invert all the bitmap to show the invert function works even if the bitmap is not loaded yet.

#ifdef LImageViewerChild 
class LImageViewerChild :public LImageViewer
{
   virtual L_INT FramesRequestedCallBack (L_INT    nCellIndex,
                                          L_UINT * puFramesRequested,
                                          L_UINT   uLength);
};
#endif
L_INT LImageViewerChild::FramesRequestedCallBack (L_INT    nCellIndex,
                               L_UINT * puFramesRequested,
                               L_UINT   uLength)
{
   L_INT nI;
   LOADFILEOPTION LoadOption;
   BITMAPHANDLE * pBitmap;
   LBitmap        BitmapHandles;
   pBITMAPHANDLE  pBitmapHandle;
   if (uLength == 0)
      return 0;
   LBaseFile::GetDefaultLoadFileOption(&LoadOption, sizeof(LOADFILEOPTION));
   pBitmap = (pBITMAPHANDLE)malloc(sizeof(BITMAPHANDLE) * uLength);
   for (nI = 0; nI < (L_INT)uLength; nI++)
   {
      LoadOption.PageNumber = puFramesRequested[nI];
      BitmapHandles.Load(TEXT("%UserProfile%\\My Documents\\LEADTOOLS Images\\xa.dcm"), 0, ORDER_BGRORGRAY, &LoadOption, NULL);
      pBitmapHandle = BitmapHandles.GetHandle();
      memcpy(&pBitmap[nI], pBitmapHandle, sizeof(BITMAPHANDLE));
      BitmapHandles.SetHandle(NULL, FALSE);
   }
   SetRequestedImage( nCellIndex, pBitmap, (L_INT *) puFramesRequested, uLength, 0);
   return SUCCESS;
}
L_INT LImageViewer_EnableCellLowMemoryUsageExample(LImageViewer& ImageViewer)
{
   FILEINFO                 FileInfo;
   pDISPCONTAINERBITMAPINFO pBitmapInfo;
   L_INT                    nI, nRet;
   LBitmapBase              LeadBitmap;
   LFile                    LeadFile;
   LeadFile.SetBitmap(&LeadBitmap) ;
   LeadFile.SetFileName(TEXT("%UserProfile%\\My Documents\\LEADTOOLS Images\\xa.dcm"));
   nRet = LeadFile.GetInfo(&FileInfo, sizeof(FILEINFO)) ;
   if(nRet != SUCCESS)
      return nRet;
   pBitmapInfo = (DISPCONTAINERBITMAPINFO *)malloc(sizeof(DISPCONTAINERBITMAPINFO) * FileInfo.TotalPages);
   for (nI = 0; nI < FileInfo.TotalPages; nI++)
   {
      pBitmapInfo[nI].uHeight = FileInfo.Height;
      pBitmapInfo[nI].uWidth = FileInfo.Width;
      pBitmapInfo[nI].uXResolution = FileInfo.XResolution;
      pBitmapInfo[nI].uYResolution = FileInfo.YResolution;
   }
   ImageViewer.InsertCell( 0, 0);
   ImageViewer.EnableLowMemoryUsageCallBack(TRUE);
   ImageViewer.EnableCellLowMemoryUsage(0,
                                        0,
                                        FileInfo.TotalPages,
                                        pBitmapInfo,
                                        0);
   // invert all the frames in the cell.
   for (nI = 0; nI < FileInfo.TotalPages; nI ++)
   {
      ImageViewer.InvertBitmap( 0, nI, 0);
   }
   return SUCCESS;
}