- stream
- A System.IO.Stream containing the input image data.
- pageNumber
- 1-based index of the page from which to read the tags.
- offsets
- An array that contains the offests for each tag.
Visual Basic (Declaration) | |
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Overloads Public Function ReadTagsWithOffsets( _ ByVal stream As Stream, _ ByVal pageNumber As Integer, _ ByRef offsets As Long() _ ) As RasterCollection(Of RasterTagMetadata) |
Visual Basic (Usage) | Copy Code |
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Dim instance As RasterCodecs Dim stream As Stream Dim pageNumber As Integer Dim offsets As Long() Dim value As RasterCollection(Of RasterTagMetadata) value = instance.ReadTagsWithOffsets(stream, pageNumber, offsets) |
C# | |
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public RasterCollection<RasterTagMetadata> ReadTagsWithOffsets( Stream stream, int pageNumber, out long[] offsets ) |
C++/CLI | |
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public: RasterCollection<RasterTagMetadata^>^ ReadTagsWithOffsets( Stream^ stream, int pageNumber, [Out] array<int64> offsets ) |
Parameters
- stream
- A System.IO.Stream containing the input image data.
- pageNumber
- 1-based index of the page from which to read the tags.
- offsets
- An array that contains the offests for each tag.
Return Value
A collection of Leadtools.RasterTagMetadata containing all the tags found in the file. If the file does not contain any tags, an empty collection will be returned. If the file format does not support tags, an exception will be thrown.
This example will load all the tags, with their offsets, from a file.
Visual Basic | Copy Code |
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Private Shared Sub ReadTagsWithOffsetsExample() ' Prompt the user for an image file Dim imageFileName As String = PromptForFileName() ' Initialize LEADTOOLS Using codecs As New RasterCodecs() ' Get the file format Dim format As RasterImageFormat Using info As CodecsImageInfo = codecs.GetInformation(imageFileName, False) format = info.Format End Using ' Load the tags, with their offsets Dim tags As RasterCollection(Of RasterTagMetadata) = Nothing Dim offsets As Long() = Nothing If RasterCodecs.TagsSupported(format) Then tags = codecs.ReadTagsWithOffsets(imageFileName, 1, offsets) End If Dim txtFileName As String = Path.Combine( _ Path.GetDirectoryName(imageFileName), _ Path.GetFileNameWithoutExtension(imageFileName) + "_metadata.txt") Using writer As StreamWriter = File.CreateText(txtFileName) ' Write the tags WriteTags(writer, "Tags", tags, offsets) End Using ' Show the text file we created System.Diagnostics.Process.Start(txtFileName) End Using End Sub Private Shared Sub WriteTags(ByVal writer As StreamWriter, ByVal name As String, ByVal tags As RasterCollection(Of RasterTagMetadata), ByVal offsets As Long()) writer.WriteLine("{0}:", name) If Not IsNothing(tags) Then Dim x As Integer = 0 For Each tag As RasterTagMetadata In tags writer.WriteLine("Id: 0x{0}, offset: {1}", tag.Id.ToString("X"), offsets(x)) x = x + 1 Next Else writer.WriteLine("Not supported") End If writer.WriteLine() End Sub |
C# | Copy Code |
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public void ReadTagsWithOffsetsExample() { // Prompt the user for an image file string imageFileName = PromptForFileName(); // Initialize LEADTOOLS using (RasterCodecs codecs = new RasterCodecs()) { // Get the file format RasterImageFormat format; using (CodecsImageInfo info = codecs.GetInformation(imageFileName, false)) { format = info.Format; } // Load the tags, with their offsets RasterCollection<RasterTagMetadata> tags = null; long[] offsets = null; if (RasterCodecs.TagsSupported(format)) tags = codecs.ReadTagsWithOffsets(imageFileName, 1, out offsets); string txtFileName = Path.Combine( Path.GetDirectoryName(imageFileName), Path.GetFileNameWithoutExtension(imageFileName) + "_metadata.txt"); using (StreamWriter writer = File.CreateText(txtFileName)) { // Write the tags WriteTags(writer, "Tags", tags, offsets); } // Show the text file we created System.Diagnostics.Process.Start(txtFileName); } } private static void WriteTags(StreamWriter writer, string name, RasterCollection<RasterTagMetadata> tags, long[] offsets) { writer.WriteLine("{0}:", name); if (tags != null) { int x = 0; foreach (RasterTagMetadata tag in tags) { writer.WriteLine("Id: 0x{0}, offset: {1}", tag.Id.ToString("X"), offsets[x]); x++; } } else { writer.WriteLine("Not supported"); } writer.WriteLine(); } |
SilverlightCSharp | Copy Code |
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SilverlightVB | Copy Code |
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To read a specific tag stored in a file, use ReadTag(String,Int32,Int32) and to enumerate all the tag ids (but not the data) stored in a file use EnumTags(String,Int32).
This method will throw an exception if the file format does not support tags. To check if a file format supports tags, use RasterCodecs.TagsSupported. You can also automatically load all the tags stored in a file during a load operation by setting the CodecsLoadOptions.Tags property to true. The tags data will be stored in the result image RasterImage.Tags collection.
To load all the tags stored in a disk file, use RasterCodecs.ReadTags.
Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only)
Reference
RasterCodecs ClassRasterCodecs Members
Overload List
TagsSupported Method
ReadTag(String,Int32,Int32) Method
EnumTags(String,Int32) Method
CommentsSupported Method
GeoKeysSupported Method
Tags Property
RasterImage.Tags
Working with Markers
Implementing TIFF Comments and Tags
TIFF File Comments
Implementing GeoKeys (GeoTIFF tags)
Leadtools.RasterCommentMetadataType