How to rotate the stamp image before adding to PDF WinForms?
The Syncfusion Essential® PDF is a feature-rich and high-performance .NET PDF library that is used to create, read, and edit PDF documents programmatically without Adobe dependencies. Using this library, you can rotate the stamp image before adding to a PDF document using C# and VB.NET.
Steps to rotate the stamp image before adding to a PDF document using C# programmatically
1. Create a new C# console application project.
2. Install the Syncfusion.PDF.WinForms NuGet packages as a reference to your .NET Framework application from NuGet.org.
3. Include the following namespaces in the Program.cs file.
C#
using Syncfusion.Pdf; using Syncfusion.Pdf.Graphics; using Syncfusion.Pdf.Interactive; using Syncfusion.Pdf.Parsing;
VB.NET
Imports Syncfusion.Pdf Imports Syncfusion.Pdf.Graphics Imports Syncfusion.Pdf.Interactive Imports Syncfusion.Pdf.Parsing
4. The following code example shows how to rotate the stamp image before adding to a PDF document using C#.
C#
// Load the PDF document
PdfLoadedDocument document = new PdfLoadedDocument("../../Data/Test File.pdf");
// Load the page
PdfLoadedPage page = document.Pages[0] as PdfLoadedPage;
// Load image from the disk
PdfBitmap bitmap = new PdfBitmap("../../Data/logo.png");
// Set the rotation angle
int rotation = -270;
// Set the points based on the rotation
RectangleF rect = CalculateTransformation(rotation, bitmap);
// Creates a new pdf rubber stamp annotation
RectangleF rectangle = new RectangleF(100, 100, rect.Width, rect.Height);
PdfRubberStampAnnotation rubberStampAnnotation = new PdfRubberStampAnnotation(rectangle);
rubberStampAnnotation.Text = "Stamp annotation with 180 degree rotated image";
// Save the current graphics state
PdfGraphicsState state = rubberStampAnnotation.Appearance.Normal.Graphics.Save();
// Translate the coordinate system
rubberStampAnnotation.Appearance.Normal.Graphics.TranslateTransform(rect.X, rect.Y);
// Rotate the coordinate system
rubberStampAnnotation.Appearance.Normal.Graphics.RotateTransform(rotation);
// Draw image
rubberStampAnnotation.Appearance.Normal.Graphics.DrawImage(bitmap, new RectangleF(0, 0, bitmap.Width, bitmap.Height));
// Restore the graphics state
rubberStampAnnotation.Appearance.Normal.Graphics.Restore(state);
// Adds annotation to the page
page.Annotations.Add(rubberStampAnnotation);
// Saves the document to disk
document.Save("TestFile_stamped.pdf");
// Close the document
document.Close(true);
Process.Start("TestFile_stamped.pdf");
//calculate the translate transformation
private static RectangleF CalculateTransformation( int rotation, PdfBitmap bitmap)
{
RectangleF rectangle = new RectangleF();
if (rotation == -45)
{
rectangle.X = bitmap.Height;
rectangle.Y = bitmap.Width;
rectangle.Width = bitmap.Width + bitmap.Height;
rectangle.Height = bitmap.Width + bitmap.Height;
}
else if (rotation == -90)
{
rectangle.X = 0;
rectangle.Y = bitmap.Width;
rectangle.Width = bitmap.Height;
rectangle.Height = bitmap.Width;
}
else if (rotation == -180)
{
rectangle.X = bitmap.Width;
rectangle.Y = bitmap.Height;
rectangle.Width = bitmap.Width;
rectangle.Height = bitmap.Height;
}
else if (rotation == -270)
{
rectangle.X = bitmap.Height;
rectangle.Y = 0;
rectangle.Width = bitmap.Height;
rectangle.Height = bitmap.Width;
}
return rectangle;
}
VB.NET
'Load the PDF document
Dim document As PdfLoadedDocument = New PdfLoadedDocument("../../Data/Test File.pdf")
'Load the page
Dim page As PdfLoadedPage = TryCast(document.Pages(0), PdfLoadedPage)
'Load image from the disk
Dim bitmap As PdfBitmap = New PdfBitmap("../../Data/logo.png")
'Set the rotation angle
Dim rotation As Integer = -270
'Set the points based on the rotation
Dim rect As RectangleF = CalculateTransformation(rotation, bitmap)
'Creates a new pdf rubber stamp annotation
Dim rectangle As RectangleF = New RectangleF(100, 100, rect.Width, rect.Height)
Dim rubberStampAnnotation As PdfRubberStampAnnotation = New PdfRubberStampAnnotation(rectangle)
rubberStampAnnotation.Text = "Stamp annotation with 180 degree rotated image"
'Save the current graphics state
Dim state As PdfGraphicsState = rubberStampAnnotation.Appearance.Normal.Graphics.Save()
'Translate the coordinate system
rubberStampAnnotation.Appearance.Normal.Graphics.TranslateTransform(rect.X, rect.Y)
'Rotate the coordinate system
rubberStampAnnotation.Appearance.Normal.Graphics.RotateTransform(rotation)
'Draw image
rubberStampAnnotation.Appearance.Normal.Graphics.DrawImage(bitmap, New RectangleF(0, 0, bitmap.Width, bitmap.Height))
'Restore the graphics state
rubberStampAnnotation.Appearance.Normal.Graphics.Restore(state)
'Adds annotation to the page
page.Annotations.Add(rubberStampAnnotation)
'Saves the document to disk
document.Save("TestFile_stamped.pdf")
'Close the document
document.Close(True)
Process.Start("TestFile_stamped.pdf")
Private Function CalculateTransformation(ByVal rotation As Integer, ByVal bitmap As PdfBitmap) As RectangleF Dim rectangle As RectangleF = New RectangleF() If rotation = -45 Then rectangle.X = bitmap.Height rectangle.Y = bitmap.Width rectangle.Width = bitmap.Width + bitmap.Height rectangle.Height = bitmap.Width + bitmap.Height End If If rotation = -90 Then rectangle.X = 0 rectangle.Y = bitmap.Width rectangle.Width = bitmap.Height rectangle.Height = bitmap.Width End If If rotation = -180 Then rectangle.X = bitmap.Width rectangle.Y = bitmap.Height rectangle.Width = bitmap.Width rectangle.Height = bitmap.Height End If If rotation = -270 Then rectangle.X = bitmap.Height rectangle.Y = 0 rectangle.Width = bitmap.Height rectangle.Height = bitmap.Width End If Return rectangle End Function
A complete working sample can be downloaded from RotateImage.zip.
By executing the program, you will get the PDF document as follows.
Take a moment to peruse the documentation. You can add the annotation to PDF document, flatten, and modifying the annotations, importing, or exporting annotation from the FDF or XFDF file, adding comments and review status to the PDF annotation, and printing annotation.
Refer to here to explore a rich set of Syncfusion Essential® PDF features.
Starting with v16.2.0.x, if you reference Syncfusion® assemblies from the trial setup or NuGet feed, include a license key in your projects. Refer to the link to learn about generating and registering the Syncfusion® license key in your application to use the components without trail message.
See Also:
https://help.syncfusion.com/file-formats/pdf/working-with-annotations
How to modify the size of the annotation in PDF using C# and VB.NET | Syncfusion
How to remove all annotations from an existing PDF document | Syncfusion
