RecolorOperation Recolor Function. Recolor pages in a document. ABCpdf .NET PDF Library.

Recolor pages in a document.

[C#]
void Recolor(Doc doc)
void Recolor(Pages pages)
void Recolor(Page page)

[Visual Basic]
Sub Recolor(doc As Doc)
Sub Recolor(pages As Pages)
Sub Recolor(page As Page)


may throw Exception()

Converts the specified pages from one color space to another.

The destination color space is specified by assigning a value to the DestinationColorSpace property. All images used on the page are converted to the new color space. All color operators used in the page content stream are converted to the new color space.

Annotations and fields are not part of the page but instead float over the page. You can choose whether to convert the appearance stream of any annotations or leave them in their native color space. This is controlled using the ConvertAnnotations property.

Colors can only be sensibly mapped from one color space to another if we know something about the characteristics of the color space. If your color spaces do not contain this information (e.g. if they are device color spaces) then ABCpdf will use a default color profile.

An exception will be thrown if the operation is not possible. This may happen if the IndirectObjects provided are not in an ObjectSoup or if the destination ColorSpace is in some way invalid.

As part of the Recolor process, all images used on the page(s) are also recolored. (See also PixMap.Recolor.) After the recolor process has been completed these PixMap objects will no longer be compressed. You may wish to analyse and recompress these images by pre and post processing them during the ProcessingObject and ProcessedObject events.

Here we recolor one page out of a document. We pick up the ProcessingObject events so that we can store the source color space for all the PixMap objects which are processed. We don't want to convert CMYK pixmaps so we set the Cancel property to true if we find these.

We then pick up the ProcessedObject events so that we can recompress the PixMap objects after they have been recolored. We vary the recompression method used dependent on the source color space and the size of the image.

Here we use standard delegates for backwards compatibility with .NET 1.1 code. However .NET 2.0 anonymous delegates will provide a more compact solution.

[C#]
Doc theDoc = new Doc();
theDoc.Read(Server.MapPath("../mypics/sample.pdf"));
MyOp.Recolor(theDoc, (Page)theDoc.ObjectSoup[theDoc.Page]);
theDoc.Save(Server.MapPath("RecolorOperation.pdf"));
theDoc.Clear();

private class MyOp{
  public static void Recolor(Doc doc, Page page) {
    RecolorOperation op = new RecolorOperation();
    op.DestinationColorSpace = new ColorSpace(doc.ObjectSoup, ColorSpaceType.DeviceGray);
    op.ConvertAnnotations = false;
    op.ProcessingObject += Recoloring;
    op.ProcessedObject += Recolored;
    op.Recolor(page);
  }

  public static void Recoloring(object sender, ProcessingObjectEventArgs e) {
    PixMap pm = e.Object as PixMap;
    if (pm != null) {
      ColorSpaceType cs = pm.ColorSpaceType;
      if (cs == ColorSpaceType.DeviceCMYK)
        e.Cancel = true;
      e.Tag = cs;
    }
  }

  public static void Recolored(object sender, ProcessedObjectEventArgs e) {
    if (e.Successful) {
      PixMap pm = e.Object as PixMap;
      if (pm != null) {
        ColorSpaceType cs = (ColorSpaceType)e.Tag;
        if (pm.Width > 1000)
          pm.CompressJpx(30);
        else if (cs == ColorSpaceType.DeviceRGB)
          pm.CompressJpeg(30);
        else
          pm.Compress(); // Flate
      }
    }
  }
}

[Visual Basic]
Dim theDoc As Doc = New Doc()
theDoc.Read(Server.MapPath("../mypics/sample.pdf"))
MyOp.Recolor(theDoc, CType(theDoc.ObjectSoup(theDoc.Page), Page))
theDoc.Save(Server.MapPath("RecolorOperation.pdf"))
theDoc.Clear()

Private Class MyOp
  Public Shared Sub Recolor(doc As Doc, page As Page)
    Dim op As New RecolorOperation()
    op.DestinationColorSpace = New ColorSpace(doc.ObjectSoup, ColorSpaceType.DeviceGray)
    op.ConvertAnnotations = False
    AddHandler op.ProcessingObject, AddressOf Recoloring
    AddHandler op.ProcessedObject, AddressOf Recolored
    op.Recolor(page)
  End Sub 'Recolor

  Public Shared Sub Recoloring(sender As Object, e As ProcessingObjectEventArgs)
    Dim pm As PixMap = TryCast(e.Object, PixMap)
    If pm IsNot Nothing Then
      Dim cs As ColorSpaceType = pm.ColorSpaceType
      If cs = ColorSpaceType.DeviceCMYK Then
        e.Cancel = True
      End If
      e.Tag = cs
    End If
  End Sub 'Recoloring

  Public Shared Sub Recolored(sender As Object, e As ProcessedObjectEventArgs)
    If e.Successful Then
      Dim pm As PixMap = TryCast(e.Object, PixMap)
      If pm IsNot Nothing Then
        Dim cs As ColorSpaceType = CType(e.Tag, ColorSpaceType)
        If pm.Width > 1000 Then
          pm.CompressJpx(30)
        Else
          If cs = ColorSpaceType.DeviceRGB Then
            pm.CompressJpeg(30)
          Else
            pm.Compress() ' Flate
          End If
        End If
      End If
    End If
  End Sub 'Recolored
End Class 'MyOp