C# Drawing.Imaging dropping GIF frames if they are identical -

i need load gif animations , convert them frame frame bitmaps. that, extracting gif file frame frame using drawing.imaging library , casting each frame bitmap.

everything works fine except times when consecutive frames same, when there no pixel difference. library seems dropping such frames.

i came conslusion simple test. have created animation of circle growing , shrinking pause between moment last circle dissapears , new 1 not yet shown. when play animation consisting of extracted bitmaps pause not present. if compare gifs of same frame-length different amounts of identical frames, returned totalframescount value different. have observed webbrowsers display identical consecutive frames correctly.

  public void drawgif(image img)     {          framedimension dimension = new framedimension(img.framedimensionslist[0]);         int framecounttotal = img.getframecount(dimension);             (int framecount = 0; framecount < framecounttotal; framecount++)         {             img.selectactiveframe(dimension, framecount);                bitmap bmp = new bitmap(img);  //cast image type bitmap                  (int = 0; < 16; i++)                 {                     (int j = 0; j < 16; j++)                     {                         color color = bmp.getpixel(i, j);                         drawpixel(i, j, 0, color.r, color.g, color.b);                      }                 } 

1. does encountered such problem?
2. as pretty new c# - there way modify .net lib ?
3. maybe there solution problem not aware of, not involve changing library?

updated code - result same

 public void drawgif(img)      {       int framecounttotal = img.getframecount(framedimension.time);        (int framecount = 0; framecount < framecounttotal; framecount++)             {     img.selectactiveframe(framedimension.time, framecount);       bitmap bmp = new bitmap(img);      (int = 0; < 16; i++)             {                 (int j = 0; j < 16; j++)                 {                         color color = bmp.getpixel(i, j);                         drawpixel(i, j, 0, color.r, color.g, color.b);                  } 

the image not saving duplicate frames, have take time of each frame account. here sample code based on this book in windows programming on how frames , correct duration. example:

public class gif {     public static list<frame> loadanimatedgif(string path)     {         //if path not found, should throw io exception         if (!file.exists(path))             throw new ioexception("file not exist");          //load image         var img = image.fromfile(path);          //count frames         var framecount = img.getframecount(framedimension.time);          //if image not animated gif, should throw         //argument exception         if (framecount <= 1)             throw new argumentexception("image not animated");          //list hold frames         var frames = new list<frame>();          //get times stored in gif         //propertytagframedelay ((propid) 0x5100) comes gdiplusimaging.h         //more info on http://msdn.microsoft.com/en-us/library/windows/desktop/ms534416(v=vs.85).aspx         var times = img.getpropertyitem(0x5100).value;          //convert 4bit duration chunk int          (int = 0; < framecount; i++)         {             //convert 4 bit value integer             var duration = bitconverter.toint32(times, 4*i);              //add new frame our list of frames             frames.add(                 new frame()                 {                     image = new bitmap(img),                     duration = duration                 });              //set write frame before save             img.selectactiveframe(framedimension.time, i);           }          //dispose image when we're done         img.dispose();          return frames;     } } 

we need structure save bitmap , duration each frame

//class store each frame public class frame  {      public bitmap image { get; set; }      public int duration { get; set;}  } 

the code load bitmap, check whether multi-frame animated gif. loops though frames construct list of separate frame objects hold bitmap , duration of each frame. simple use:

var framelist = gif.loadanimatedgif ("a.gif");  var = 0; foreach(var frame in framelist)     frame.image.save ("frame_" + i++ + ".png");