Markers Property

The collection of marker data used when reading and writing certain file formats (including JPEG).

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

public RasterCollection<RasterMarkerMetadata> Markers {get;}

'Declaration
 
Public ReadOnly Property Markers As RasterCollection(Of RasterMarkerMetadata)

'Usage
 
Dim instance As RasterImage
Dim value As RasterCollection(Of RasterMarkerMetadata)
 
value = instance.Markers

public RasterCollection<RasterMarkerMetadata> Markers {get;}

 get_Markers();

public:
property RasterCollection<RasterMarkerMetadata^>^ Markers {
   RasterCollection<RasterMarkerMetadata^>^ get();
}

Property Value

A collection of RasterMarkerMetadata used when reading and writing certain file formats (including JPEG).

Remarks

Several formats allow you to store non-image data such as comments, tags, and markers.

You can manipulate the markers of an image by adding/removing RasterMarkerMetadata objects to this collection.

By setting the CodecsSaveOptions.Markers property to true before calling RasterCodecs.Save, you can save the markers in this collection when the image is saved into a file.

By setting the CodecsLoadOptions.Markers property to true before calling RasterCodecs.Load, you can load all the markers (if any) into this collection when an image is loaded from a file.

You can use the RasterCodecs.ReadMarkers method to load the markers directly from an existing file and the RasterCodecs.WriteMarkers method to save the markers to an existing file.

For more information, refer to Non Image Data.

Example

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Public Sub MarkersExample()
      Dim codecs As RasterCodecs = New RasterCodecs()
      Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"))

      Dim byteData As Byte() = New Byte(0) {}
      byteData(0) = 40
      ' write APP5 (since nobody writes that)
      Dim markerData As RasterMarkerMetadata = New RasterMarkerMetadata(RasterMarkerMetadata.App0 + 5, byteData)
      image.Markers.Add(markerData)

      codecs.Options.Save.Markers = True
      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_MARKERS.JPG"), RasterImageFormat.Jpeg, 0)

      ' load the marker together with the image
      Dim marker As RasterCollection(Of RasterMarkerMetadata) = codecs.ReadMarkers(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_MARKERS.JPG"))
      ' look for the APP5 marker, because there might be other markers (like APP0, APP1)
      For Each markerItem As RasterMarkerMetadata In marker
         If markerItem.Id = RasterMarkerMetadata.App0 + 5 Then
            MessageBox.Show("marker Id :" & markerItem.Id.ToString() & " = " & markerItem.GetData().ToString())
         End If
      Next markerItem

      codecs.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

public void MarkersExample()
   {
      RasterCodecs codecs = new RasterCodecs();
      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir,"IMAGE1.CMP"));

      byte[] byteData = new byte[1];
      byteData[0] = 40;
      // write APP5 (since nobody writes that)
      RasterMarkerMetadata markerData = new RasterMarkerMetadata(RasterMarkerMetadata.App0 + 5, byteData);
      image.Markers.Add(markerData);

      codecs.Options.Save.Markers = true;
      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_MARKERS.JPG"), RasterImageFormat.Jpeg, 0);

      // load the marker together with the image
      RasterCollection<RasterMarkerMetadata> marker = codecs.ReadMarkers(Path.Combine(LEAD_VARS.ImagesDir,"IMAGE1_MARKERS.JPG"));
      // look for the APP5 marker, because there might be other markers (like APP0, APP1)
      foreach(RasterMarkerMetadata markerItem in marker)
         if(markerItem.Id == RasterMarkerMetadata.App0 + 5)
            MessageBox.Show("marker Id :" + markerItem.Id.ToString() + " = " + markerItem.GetData().ToString());

      codecs.Dispose();
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

RasterImageExamples.prototype.MarkersExample = function () {
   Tools.SetLicense();
   with (Leadtools) {
      with (Leadtools.Codecs) {
         var codecs = new RasterCodecs();
         var srcFileName = "Assets\\Image1.cmp";
         var image;

         return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) {

            return codecs.loadAsync(LeadStreamFactory.create(loadFile))
         })
            .then(function (img) {
               image = img;

               var byteData = new Array(1);
               byteData[0] = 40;
               // write APP5 (since nobody writes that)
               var markerData = new RasterMarkerMetadata(RasterMarkerMetadata.app0 + 5, byteData);
               image.markers.append(markerData);

               codecs.options.save.markers = true;
               return Tools.AppLocalFolder().createFileAsync("IMAGE1_MARKERS.JPG")
            })
            .then(function (saveFile) {
               var saveStream = LeadStreamFactory.create(saveFile);
               return codecs.saveAsync(image, saveStream, RasterImageFormat.jpeg, 0)
            })
            .then(function () {
               // load the marker together with the image
               return Tools.AppLocalFolder().getFileAsync("IMAGE1_MARKERS.JPG")
            })
            .then(function (loadFile) {
               return codecs.readMarkersAsync(LeadStreamFactory.create(loadFile))
            })
            .then(function (marker) {
               // look for the APP5 marker, because there might be other markers (like APP0, APP1)
               for (var i = 0; i < marker.length; i++) {
                  var markerItem = marker[i];

                  if (markerItem.id == RasterMarkerMetadata.app0 + 5)
                     console.info("marker Id :" + markerItem.id + " Length : " + markerItem.getData().length);
               }
               image.close();
               codecs.close();
            });
      }
   }
}

[TestMethod]
public async Task MarkersExample()
{
   RasterCodecs codecs = new RasterCodecs();
   string srcFileName = @"Assets\Image1.cmp";
   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));
   byte[] byteData = new byte[1];
   byteData[0] = 40;
   // write APP5 (since nobody writes that)
   RasterMarkerMetadata markerData = new RasterMarkerMetadata(RasterMarkerMetadata.App0 + 5, byteData);
   image.Markers.Add(markerData);

   codecs.Options.Save.Markers = true;
   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync("IMAGE1_MARKERS.JPG");
   ILeadStream saveStream = LeadStreamFactory.Create(saveFile);
   await codecs.SaveAsync(image, saveStream, RasterImageFormat.Jpeg, 0);

   // load the marker together with the image
   loadFile = await Tools.AppLocalFolder.GetFileAsync("IMAGE1_MARKERS.JPG");
   IList<RasterMarkerMetadata> marker = await codecs.ReadMarkersAsync(LeadStreamFactory.Create(loadFile));
   // look for the APP5 marker, because there might be other markers (like APP0, APP1)
   foreach (RasterMarkerMetadata markerItem in marker)
   {
      if (markerItem.Id == RasterMarkerMetadata.App0 + 5)
         Debug.WriteLine("marker Id :" + markerItem.Id + " Length : " + markerItem.GetData().Length);
   }

   codecs.Dispose();
}

public void MarkersExample(RasterImage image, Stream destStream)
{
   byte[] byteData = new byte[1];
   byteData[0] = 40;
   // write APP5 (since nobody writes that)
   RasterMarkerMetadata markerData = new RasterMarkerMetadata(RasterMarkerMetadata.App0 + 5, byteData);
   image.Markers.Add(markerData);
   RasterCodecs codecs = new RasterCodecs();
   codecs.Options.Save.Markers = true;
   codecs.Save(image, destStream, RasterImageFormat.Jpeg, 0);

   // load the marker together with the image
   RasterCollection<RasterMarkerMetadata> marker = codecs.ReadMarkers(destStream);
   // look for the APP5 marker, because there might be other markers (like APP0, APP1)
   foreach (RasterMarkerMetadata markerItem in marker)
      if (markerItem.Id == RasterMarkerMetadata.App0 + 5)
         Debug.WriteLine("marker Id :" + markerItem.Id.ToString() + " = " + markerItem.GetData().ToString());
}

Public Sub MarkersExample(ByVal image As RasterImage, ByVal destStream As Stream)
   Dim byteData As Byte() = New Byte(0){}
   byteData(0) = 40
   ' write APP5 (since nobody writes that)
   Dim markerData As RasterMarkerMetadata = New RasterMarkerMetadata(RasterMarkerMetadata.App0 + 5, byteData)
   image.Markers.Add(markerData)
   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Options.Save.Markers = True
   codecs.Save(image, destStream, RasterImageFormat.Jpeg, 0)

   ' load the marker together with the image
   Dim marker As RasterCollection(Of RasterMarkerMetadata) = codecs.ReadMarkers(destStream)
   ' look for the APP5 marker, because there might be other markers (like APP0, APP1)
   For Each markerItem As RasterMarkerMetadata In marker
      If markerItem.Id = RasterMarkerMetadata.App0 + 5 Then
         Debug.WriteLine("marker Id :" & markerItem.Id.ToString() & " = " & markerItem.GetData().ToString())
      End If
   Next markerItem
End Sub

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

RasterImage Class
RasterImage Members