winapi - Bitmap Support In C++ -

below snippet i've taken msdn example chops video stream in small thumbnails @ selected intervals:

 //------------------------------------------------------------------- // createbitmaps // // creates array of thumbnails video file. // // prt:      direct2d render target. used create bitmaps. // count:    number of thumbnails create. // psprites: array of sprite objects hold bitmaps. // // note: caller allocates sprite objects. //-------------------------------------------------------------------  hresult thumbnailgenerator::createbitmaps( id2d1rendertarget *prt,  dword count,  sprite psprites[] ) { hresult hr = s_ok; bool bcanseek = 0;  longlong hnsduration = 0; longlong hnsrangestart = 0; longlong hnsrangeend = 0; longlong hnsincrement = 0;  hr = canseek(&bcanseek);  if (failed(hr)) { return hr; }  if (bcanseek) {     hr = getduration(&hnsduration);      if (failed(hr)) { return hr; }      hnsrangestart = 0;     hnsrangeend = hnsduration;      // have file duration , we'll take bitmaps     // several positions in file. occasionally, first frame      // in video black, don't start @ time 0.      hnsincrement = (hnsrangeend - hnsrangestart) / (count + 1);  }  // generate bitmaps , invalidate button controls // redrawn. (dword = 0; < count; i++) {     longlong hpos = hnsincrement * (i + 1);      hr = createbitmap(         prt,          hpos,          &psprites[i]     ); }  return hr; }   // /// private methods //  //-------------------------------------------------------------------  // createbitmap  // // creates 1 video thumbnail. // // prt:      direct2d render target. used create bitmap. // hnspos:   seek position. // psprite:  sprite object hold bitmap. //-------------------------------------------------------------------  hresult thumbnailgenerator::createbitmap( id2d1rendertarget *prt,  longlong& hnspos,  sprite *psprite ) { hresult     hr = s_ok; dword       dwflags = 0;  byte        *pbitmapdata = null;    // bitmap data dword       cbbitmapdata = 0;       // size of data, in bytes longlong    hnstimestamp = 0; bool        bcanseek = false;       // can source seek?   dword       cskipped = 0;           // number of skipped frames  imfmediabuffer *pbuffer = 0; imfsample *psample = null; id2d1bitmap *pbitmap = null;  hr = canseek(&bcanseek); if (failed(hr))  {      return hr;  }  if (bcanseek && (hnspos > 0)) {     propvariant var;     propvariantinit(&var);      var.vt = vt_i8;     var.hval.quadpart = hnspos;      hr = m_preader->setcurrentposition(guid_null, var);      if (failed(hr)) { goto done; }  }   // pulls video frames source reader.  // note: seeking might inaccurate, depending on container //       format , how file indexed. therefore, first //       frame might earlier desired time. //       if so, skip max_frames_to_skip frames.  while (1) {     imfsample *psampletmp = null;      hr = m_preader->readsample(         (dword)mf_source_reader_first_video_stream,          0,          null,          &dwflags,          null,          &psampletmp         );      if (failed(hr)) { goto done; }      if (dwflags & mf_source_readerf_endofstream)     {         break;     }      if (dwflags & mf_source_readerf_currentmediatypechanged)     {         // type change. new format.         hr = getvideoformat(&m_format);          if (failed(hr)) { goto done; }     }      if (psampletmp == null)     {         continue;     }      // got sample. hold onto it.      saferelease(&psample);      psample = psampletmp;     psample->addref();      if (succeeded( psample->getsampletime(&hnstimestamp) ))     {         // keep going until frame within tolerance of         // desired seek position, or until skip max_frames_to_skip frames.          // during process, might reach end of file,         // cache last sample got (psample).          if ( (cskipped < max_frames_to_skip) &&               (hnstimestamp + seek_tolerance < hnspos) )           {             saferelease(&psampletmp);              ++cskipped;             continue;         }     }      saferelease(&psampletmp);      hnspos = hnstimestamp;     break;  }   if (psample)  {     uint32 pitch = 4 * m_format.imagewidthpels;       // bitmap data sample, , use create     // direct2d bitmap object. use direct2d bitmap      // initialize sprite.      hr = psample->converttocontiguousbuffer(&pbuffer);      if (failed(hr)) { goto done; }      hr = pbuffer->lock(&pbitmapdata, null, &cbbitmapdata);      if (failed(hr)) { goto done; }      assert(cbbitmapdata == (pitch * m_format.imageheightpels));      hr = prt->createbitmap(          d2d1::sizeu(m_format.imagewidthpels, m_format.imageheightpels),         pbitmapdata,         pitch,         d2d1::bitmapproperties(              // format = rgb32             d2d1::pixelformat(dxgi_format_b8g8r8a8_unorm, d2d1_alpha_mode_ignore)              ),         &pbitmap         );      if (failed(hr)) { goto done; }      psprite->setbitmap(pbitmap, m_format);     }     else     {     hr = mf_e_end_of_stream;     }  done:  if (pbitmapdata) {     pbuffer->unlock(); } saferelease(&pbuffer); saferelease(&psample); saferelease(&pbitmap);  return hr; } 

instead of bitmaps being placed inside sprite objects (passed in array), want method return array of bitmaps. msdn suggests bitmap class exist c++ though can't seem include reference class. want compile class dll , use in c# project can pass uri movie , have chopped , returned bitmap frames these methods. can take care of logic myself, need know how make code handle , return bitmap[] of frames createbitmaps() method.

using windows api, can create bitmap. so, instead of doing:

psprite->setbitmap(pbitmap, m_format); 

you should pass pointer bitmap object parameter createbitmap function , use in function:

  *pbitmap =  new bitmap(int width, int height, int stride, pixelformat format, byte *scan0); 

in above, replace *scan0 pointer bitmap data in bytes (which believe in code pbitmap) , rest of information regarding height, width, pixelformat etc, m_format variable.

this should work you.

note: please include gdi+ headers bitmap class part of it.

hope helps.

p.s. if averse using gdi+ classes, can try bitmap object msdn offers part of windows gdi. though personally, feel offers lot less functionality , takes longer code.