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LoadInformation Event

Occurs during loading of a file for which LEADTOOLS cannot recognize the format.
public event EventHandler<CodecsLoadInformationEventArgs> LoadInformation 
synchronized public void addLoadInformationListener(CodecsLoadInformationListener listener) 
synchronized public void removeLoadInformationListener(CodecsLoadInformationListener listener) 
event EventHandler<CodecsLoadInformationEventArgs^>^ LoadInformation 
def LoadInformation(sender,e): # sender: RasterCodecs e: CodecsLoadInformationEventArgs 
Event Data

The event handler receives an argument of type CodecsLoadInformationEventArgs containing data related to this event. The following CodecsLoadInformationEventArgs properties provide information specific to this event.

BitsPerPixel Gets or sets the bits per pixel of the image data in the file.
Format Gets the image file format.
Height Gets or sets the image height in pixels.
LeastSignificantBitFirst Gets or sets a value specifying whether the image data was saved with least significant bit first or last.
MotorolaOrder Gets or sets a value that determines whether image data is in Motorola byte order.
Offset Gets or sets the position of the first byte of image data.
Order Gets or sets the byte order for the load process.
Pad4 Gets or sets a value indicating whether the image data was saved padded to 4-byte boundary.
PhotoInterpolation Gets or sets the photometric interpolation for the load process.
PlanarConfiguration Gets or sets the planar configuration.
Reverse Gets or sets a value that determines whether each line is reversed (mirrored).
Signed Gets or sets a value that determines whether the image data is signed.
Stream Gets the stream used by the load process.
StripSize Gets or sets the size of the data strip before it is decompressed.
ViewPerspective Gets or sets the view perspective for the load process.
WhiteOnBlack Gets or sets a value that determines if the image is black-on-white or white on black.
Width Gets or sets the image width in pixels.
XResolution Gets or sets the horizontal resolution for rendering the image, specified in dots per inch.
YResolution Gets or sets the vertical resolution for rendering the image, specified in dots per inch.

The LoadInformation event will occur when LEADTOOLS cannot recognize the image file format during a call to GetInformation or GetInformationAsync. This event can be used for loading raw FAX data (CCITT Group 3 or Group 4), raw run-length-encoded data (4-bit or 8-bit), raw Bitfield compressed data, raw PackBits compressed data or raw uncompressed data.

To load a raw fax file, you must subscribe to this event first. When the toolkit fails to recognize the image file format, it will fire this event. If you know the size of the fax image, then set the values in the CodecsLoadInformationEventArgs.Width and CodecsLoadInformationEventArgs.Height properties of the CodecsLoadInformationEventArgs passed as the event data. To automatically detect the width and height of the fax file, set CodecsLoadInformationEventArgs.Width and CodecsLoadInformationEventArgs.Height to -1.

To load raw uncompressed data, you must subscribe to this event first. When the toolkit fails to recognize the image file format, it will fire this event. Set the CodecsLoadInformationEventArgs.Format property to RasterImageFormat.Raw. Valid values must also be set for the following properties:

If each line of RAW data is padded so that the number of bytes is a multiple of 4 (as is the case with raw Windows BMP data), set CodecsLoadInformationEventArgs.Pad4 to true. Include an orientation in the CodecsLoadInformationEventArgs.ViewPerspective to load with the proper orientation. For example, raw Windows BMP data is stored with a RasterViewPerspective.BottomLeft orientation. If the orientation is unknown, then set it to RasterViewPerspective.BottomLeft. If the raw data is 8 bits per pixel or less, then the image is palettized and a palette must be generated. If this is the case, pass in a valid palette with 1 << bits/pixel (2 ^ BitsPerPixel) number of entries to the CodecsLoadInformationEventArgs.SetPalette method.

Set the correct color order in the CodecsLoadInformationEventArgs.Order property. For example, if the order of the data is BGR, then set this value to RasterByteOrder.Bgr.

For more information, refer to CodecsLoadInformationEventArgs.


This example demonstrates saving and loading raw/headerless image files.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Svg; 
private struct RawData 
   public int Width;                               // Width of image 
   public int Height;                              // Height of image 
   public int BitsPerPixel;                        // Bits per pixel of image--if palettized, a gray palette is generated 
   public RasterViewPerspective ViewPerspective;   // View perspective of raw data (TopLeft, BottomLeft, etc) 
   public RasterByteOrder Order;                   // Rgb or Bgr 
   public int XResolution;                         // Horizontal resolution in DPI 
   public int YResolution;                         // Vertical resolution in DPI 
   public int Offset;                              // Offset into file where raw data begins 
   public bool Padding;                            // true if each line of data is padded to four bytes 
   public bool ReverseBits;                        // true if the bits of each byte are reversed  
private RawData myRawData; 
private void codecs_LoadInformation(object sender, CodecsLoadInformationEventArgs e) 
   // Set the information 
   e.Format = RasterImageFormat.Raw; 
   e.Width = myRawData.Width; 
   e.Height = myRawData.Height; 
   e.BitsPerPixel = myRawData.BitsPerPixel; 
   e.XResolution = myRawData.XResolution; 
   e.YResolution = myRawData.YResolution; 
   e.Offset = myRawData.Offset; 
   e.MotorolaOrder = false; 
   e.PhotoInterpolation = CodecsPhotoInterpolation.WhiteIsZero; 
   e.PlanarConfiguration = CodecsPlanarConfiguration.PlanarFormat; // This value is used only if Format is RasterImageFormat.RawPackBits 
   e.Reverse = true; 
   e.StripSize = 10; 
   e.WhiteOnBlack = false; 
   Debug.WriteLine($"Stream: {e.Stream.ToString()}"); 
   if (myRawData.Padding) 
      e.Pad4 = true; 
   e.Order = myRawData.Order; 
   if (myRawData.ReverseBits) 
      e.LeastSignificantBitFirst = true; 
   e.ViewPerspective = myRawData.ViewPerspective; 
   // If image is palettized create a grayscale palette 
   if (e.BitsPerPixel <= 8) 
      int colors = 1 << e.BitsPerPixel; 
      RasterColor[] palette = new RasterColor[colors]; 
      for (int i = 0; i < palette.Length; i++) 
         byte val = (byte)((i * 255) / (colors - 1)); 
         palette[i] = new RasterColor(val, val, val); 
public void LoadInformationExample() 
   // First, load a JPEG or CMP file 
   string srcFilename = Path.Combine(LEAD_VARS.ImagesDir, "IMAGE2.CMP"); 
   string rawFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.raw"); 
   RasterCodecs codecs = new RasterCodecs(); 
   RasterImage image = codecs.Load(srcFilename); 
   // Save this image as RAW data 
   // Set RAW options 
   codecs.Options.Raw.Save.Pad4 = true; 
   codecs.Options.Raw.Save.ReverseBits = true; 
   codecs.Options.Save.OptimizedPalette = true; 
   codecs.Save(image, rawFileName, RasterImageFormat.Raw, 0); 
   // Save information about this image so we can use it to load the RAW file 
   myRawData = new RawData(); 
   myRawData.Width = image.Width; 
   myRawData.Height = image.Height; 
   myRawData.BitsPerPixel = image.BitsPerPixel; 
   myRawData.ViewPerspective = image.ViewPerspective; 
   myRawData.Order = image.Order; 
   myRawData.XResolution = image.XResolution; 
   myRawData.YResolution = image.YResolution; 
   myRawData.Offset = 0; 
   myRawData.Padding = true; 
   myRawData.ReverseBits = true; 
   // We dont need the image anymore 
   // Now load this RAW image back 
   // First subscribe to the LoadInformation event so we can set the image information 
   codecs.LoadInformation += new EventHandler<CodecsLoadInformationEventArgs>(codecs_LoadInformation); 
   // Load the image 
   image = codecs.Load(rawFileName); 
   // Unsubscribe from the event 
   codecs.LoadInformation -= new EventHandler<CodecsLoadInformationEventArgs>(codecs_LoadInformation); 
   // save it as bmp for testing 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Image1_raw.bmp"), RasterImageFormat.Bmp, 0); 
   // Clean up 
static class LEAD_VARS 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 

Target Platforms

Help Version 22.0.2023.5.5
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Leadtools.Codecs Assembly

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.