RetrieveDataFromImage Property

Gets or sets a value that indicates whether to automatically populate the scanline buffers in CodecsSaveImageEventArgs when using the RasterCodecs.SaveImage event.

Syntax

C#
Visual Basic
WinRT C#
Java
Objective-C
WinRT JavaScript
C++

public bool RetrieveDataFromImage {get; set;}

'Declaration

Public Property RetrieveDataFromImage As Boolean

'Usage

Dim instance As CodecsSaveOptions
Dim value As Boolean
 
instance.RetrieveDataFromImage = value
 
value = instance.RetrieveDataFromImage

public bool RetrieveDataFromImage {get; set;}

@property (nonatomic, assign) BOOL retrieveDataFromImage

public boolean getRetrieveDataFromImage()
public void setRetrieveDataFromImage(boolean value)

 <br/>get_RetrieveDataFromImage();<br/>set_RetrieveDataFromImage(value);<br/>Object.defineProperty('RetrieveDataFromImage');

public:
property bool RetrieveDataFromImage {
   bool get();
   void set (    bool value);
}

Property Value

true to automatically populate the scanline buffers in CodecsSaveImageEventArgs when using the RasterCodecs.SaveImage event, or false to make the user responsible for populating the scanline buffers. Default value is false.

Remarks

The Buffer property works as the input and output buffer containing the image data to save. If the value of RetrieveDataFromImage is set to false (the default), then the user is always responsible for providing the image data by setting in Buffer. If the value of RetrieveDataFromImage is set to true, then the RasterCodecs object will populate the Buffer prior to raising this event. The user can then inspect or modify the scanlines data or simple ignore it to save the original image data as is.

Notice that on either case, the user must provide the scanline data in the source image original format (stored in the Image property. The RasterCodecs object will then convert this data to the appropriate output format if needed, for example, if the user instructed the RasterCodecs object to save the image in a different file format than the original image.

Example

The following example shows how to use RetrieveDataFromImage to:

Save the image without instructing RasterCodecs to automatically populate the data. Resulting in an output file with a blank image.
Save the image while RasterCodecs to automatically populate the data. Resulting in a correct output image.
Save the image with RasterCodecs automatically generating the data then manipulating it to generate an output file that is an invert of the original image.

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

Copy Code

Imports Leadtools
Imports Leadtools.Codecs

Private myMode As Integer
      
Public Sub RetrieveDataFromImageExample()
   Using codecs As New RasterCodecs()
      Dim srcFile As String = Path.Combine(LEAD_VARS.ImagesDir, "Sample1.cmp")
      Dim blankFile As String = Path.Combine(LEAD_VARS.ImagesDir, "Sample1_Blank.bmp")
      Dim defaultFile As String = Path.Combine(LEAD_VARS.ImagesDir, "Sample1_Default.bmp")
      Dim invertedFile As String = Path.Combine(LEAD_VARS.ImagesDir, "Sample1_Inverted.bmp")

      ' Load the source image
      Using image As RasterImage = codecs.Load(srcFile)
         ' Subscribe to the SaveImage event
         AddHandler codecs.SaveImage, AddressOf codecs_SaveImage

         ' First, set RetrieveDataFromImage to false and save
         ' This should generate a blank image
         myMode = 0
         codecs.Options.Save.RetrieveDataFromImage = False
         codecs.Save(image, blankFile, RasterImageFormat.Bmp, 24)

         ' Next, set RetrieveDataFromImage to true but do not
         ' change the data, this should generate the correct image and is the equivalant
         ' to calling Save without subscribing to SaveImage
         myMode = 1
         codecs.Options.Save.RetrieveDataFromImage = True
         codecs.Save(image, defaultFile, RasterImageFormat.Bmp, 24)

         ' Finally, leave RetrieveDataFromImage as true but change the data by inverting
         ' the scanlines, this should generate an inverted image
         myMode = 2
         codecs.Save(image, invertedFile, RasterImageFormat.Bmp, 24)

         RemoveHandler codecs.SaveImage, AddressOf codecs_SaveImage
      End Using
   End Using

End Sub

Private Sub codecs_SaveImage(ByVal sender As Object, ByVal e As CodecsSaveImageEventArgs)
   ' This example works with 24 bpp images only
   Debug.Assert(e.Image.BitsPerPixel = 24)

   Select Case myMode
      Case 0
         ' Do not do anything

      Case 1
         ' Do not do anything

      Case 2
         ' Invert the image data
         Dim scanlineLength As Integer = e.Image.BytesPerLine
         Dim scanline(scanlineLength - 1) As Byte

         ' Loop through all the scanlines in the data
         For y As Integer = 0 To e.Lines - 1
            ' Get this row
            e.Buffer.GetData(y * scanlineLength, scanline, 0, scanlineLength)

            ' Process it by inverting every pixel data
            For x As Integer = 0 To scanlineLength - 1
               scanline(x) = CByte(255 - scanline(x))
            Next

            ' Copy it back to the event buffer
            e.Buffer.SetData(y * scanlineLength, scanline, 0, scanlineLength)
         Next
   End Select
End Sub

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

using Leadtools;
using Leadtools.Codecs;

private int myMode;
      
public void RetrieveDataFromImageExample()
{
   using (RasterCodecs codecs = new RasterCodecs())
   {
      string srcFile = Path.Combine(LEAD_VARS.ImagesDir, "Sample1.cmp");
      string blankFile = Path.Combine(LEAD_VARS.ImagesDir, "Sample1_Blank.bmp");
      string defaultFile = Path.Combine(LEAD_VARS.ImagesDir, "Sample1_Default.bmp");
      string invertedFile = Path.Combine(LEAD_VARS.ImagesDir, "Sample1_Inverted.bmp");
      // Load the source image
      using (RasterImage image = codecs.Load(srcFile))
      {
         // Subscribe to the SaveImage event
         codecs.SaveImage += new EventHandler<CodecsSaveImageEventArgs>(codecs_SaveImage);

         // First, set RetrieveDataFromImage to false and save
         // This should generate a blank image
         myMode = 0;
         codecs.Options.Save.RetrieveDataFromImage = false;
         codecs.Save(image, blankFile, RasterImageFormat.Bmp, 24);

         // Next, set RetrieveDataFromImage to true but do not
         // change the data, this should generate the correct image and is the equivalant
         // to calling Save without subscribing to SaveImage
         myMode = 1;
         codecs.Options.Save.RetrieveDataFromImage = true;
         codecs.Save(image, defaultFile, RasterImageFormat.Bmp, 24);

         // Finally, leave RetrieveDataFromImage as true but change the data by inverting
         // the scanlines, this should generate an inverted image
         myMode = 2;
         codecs.Save(image, invertedFile, RasterImageFormat.Bmp, 24);

         codecs.SaveImage -= new EventHandler<CodecsSaveImageEventArgs>(codecs_SaveImage);
      }
   }
}

private void codecs_SaveImage(object sender, CodecsSaveImageEventArgs e)
{
   // This example works with 24 bpp images only
   Debug.Assert(e.Image.BitsPerPixel == 24);

   switch (myMode)
   {
      case 0:
         // Do not do anything
         break;

      case 1:
         // Do not do anything
         break;

      case 2:
         // Invert the image data
         {
            int scanlineLength = e.Image.BytesPerLine;
            byte[] scanline = new byte[scanlineLength];

            // Loop through all the scanlines in the data
            for (int y = 0; y < e.Lines; y++)
            {
               // Get this row
               e.Buffer.GetData(y * scanlineLength, scanline, 0, scanlineLength);

               // Process it by inverting every pixel data
               for (int x = 0; x < scanlineLength; x++)
               {
                  scanline[x] = (byte)(255 - scanline[x]);
               }

               // Copy it back to the event buffer
               e.Buffer.SetData(y * scanlineLength, scanline, 0, scanlineLength);
            }
         }
         break;
   }
}

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

var  myMode;

CodecsOptionsExamples.prototype.RetrieveDataFromImageExample = function () {
   Tools.SetLicense();
   with (Leadtools) {
      with (Leadtools.Codecs) {
         
         var codecs = new RasterCodecs();
         Leadtools.RasterSupport.initialize();
         codecs.eventsDispatchMode = Leadtools.LeadEventsDispatchMode.useCoreDispatcher;
         var srcFileName = "Assets\\Image1.cmp";

         var blankFile = "Sample1_Blank.bmp";
         var defaultFile = "Sample1_Default.bmp";
         var invertedFile = "Sample1_Inverted.bmp";
         var image ;

         // Load the source image
         return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) {
            return codecs.loadAsync(LeadStreamFactory.create(loadFile))
         })
            .then(function (img) {
               image = img;

               // Subscribe to the SaveImage event
               codecs.addEventListener("saveimage", codecs_SaveImage);

               // First, set RetrieveDataFromImage to false and save
               // This should generate a blank image
               myMode = 0;
               codecs.options.save.retrieveDataFromImage = false;
               return Tools.AppLocalFolder().createFileAsync(blankFile)
            })
            .then(function (saveFile) {
               return codecs.saveAsync(image, LeadStreamFactory.create(saveFile), RasterImageFormat.bmp, 24)
            })
            .then(function () {

               // Next, set RetrieveDataFromImage to true but do not
               // change the data, this should generate the correct image and is the equivalant
               // to calling Save without subscribing to SaveImage
               myMode = 1;
               codecs.options.save.retrieveDataFromImage = true;
               return Tools.AppLocalFolder().createFileAsync(defaultFile)
            })
            .then(function (saveFile) {
               return codecs.saveAsync(image, LeadStreamFactory.create(saveFile), RasterImageFormat.bmp, 24)
            })
            .then(function () {

               // Finally, leave RetrieveDataFromImage as true but change the data by inverting
               // the scanlines, this should generate an inverted image
               myMode = 2;
               return Tools.AppLocalFolder().createFileAsync(invertedFile)
            })
            .then(function (saveFile) {
               return codecs.saveAsync(image, LeadStreamFactory.create(saveFile), RasterImageFormat.bmp, 24)
            })
            .then(function () {
               codecs.removeEventListener("saveimage", codecs_SaveImage);
               codecs.close();
            });
      }
   }
}


function codecs_SaveImage(e) {
   // This example works with 24 bpp images only
   console.assert(e.image.bitsPerPixel == 24, "e.image.bitsPerPixel == 24");

   switch (myMode) {
      case 0:
         // Do not do anything
         break;

      case 1:
         // Do not do anything
         break;

      case 2:
         // Invert the image data
         {
            var scanlineLength = e.image.bytesPerLine;
            var scanline = new Array(scanlineLength);

            // Loop through all the scanlines in the data
            for (var y = 0; y < e.lines; y++) {
               // Get this row
               e.buffer.getData(y * scanlineLength, scanline, 0, scanlineLength);

               // Process it by inverting every pixel data
               for (var x = 0; x < scanlineLength; x++) {
                  scanline[x] = Tools.ToByte(255 - scanline[x]);
               }

               // Copy it back to the event buffer
               e.buffer.setData(y * scanlineLength, scanline, 0, scanlineLength);
            }
         }
         break;
   }
}

using Leadtools;
using Leadtools.Codecs;

private int myMode;
      
public async Task RetrieveDataFromImageExample()
{
   using (RasterCodecs codecs = new RasterCodecs())
   {
      string srcFileName = @"Assets\Image1.cmp";
      string blankFile = "Sample1_Blank.bmp";
      string defaultFile = "Sample1_Default.bmp";
      string invertedFile = "Sample1_Inverted.bmp";

      // Load the source image
      StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
      using (RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile)))
      {
         // Subscribe to the SaveImage event
         codecs.SaveImage += new EventHandler<CodecsSaveImageEventArgs>(codecs_SaveImage);

         // First, set RetrieveDataFromImage to false and save
         // This should generate a blank image
         myMode = 0;
         codecs.Options.Save.RetrieveDataFromImage = false;
         StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(blankFile);
         await codecs.SaveAsync(image, LeadStreamFactory.Create(saveFile), RasterImageFormat.Bmp, 24);

         // Next, set RetrieveDataFromImage to true but do not
         // change the data, this should generate the correct image and is the equivalant
         // to calling Save without subscribing to SaveImage
         myMode = 1;
         codecs.Options.Save.RetrieveDataFromImage = true;
         saveFile = await Tools.AppLocalFolder.CreateFileAsync(defaultFile);
         await codecs.SaveAsync(image, LeadStreamFactory.Create(saveFile), RasterImageFormat.Bmp, 24);

         // Finally, leave RetrieveDataFromImage as true but change the data by inverting
         // the scanlines, this should generate an inverted image
         myMode = 2;
         saveFile = await Tools.AppLocalFolder.CreateFileAsync(invertedFile);
         await codecs.SaveAsync(image, LeadStreamFactory.Create(saveFile), RasterImageFormat.Bmp, 24);

         codecs.SaveImage -= new EventHandler<CodecsSaveImageEventArgs>(codecs_SaveImage);
      }
   }
}

private void codecs_SaveImage(object sender, CodecsSaveImageEventArgs e)
{
   // This example works with 24 bpp images only
   Assert.IsTrue(e.Image.BitsPerPixel == 24);

   switch (myMode)
   {
      case 0:
         // Do not do anything
         break;

      case 1:
         // Do not do anything
         break;

      case 2:
         // Invert the image data
         {
            int scanlineLength = e.Image.BytesPerLine;
            byte[] scanline = new byte[scanlineLength];

            // Loop through all the scanlines in the data
            for (int y = 0; y < e.Lines; y++)
            {
               // Get this row
               e.Buffer.GetData(y * scanlineLength, scanline, 0, scanlineLength);

               // Process it by inverting every pixel data
               for (int x = 0; x < scanlineLength; x++)
               {
                  scanline[x] = (byte)(255 - scanline[x]);
               }

               // Copy it back to the event buffer
               e.Buffer.SetData(y * scanlineLength, scanline, 0, scanlineLength);
            }
         }
         break;
   }
}

Requirements

Target Platforms

Reference

CodecsSaveOptions Class
CodecsSaveOptions Members