C#/VB.NET : ajouter, masquer ou supprimer des calques dans un PDF

PM> Install-Package Spire.PDF

using Spire.Pdf;
    using Spire.Pdf.Graphics;
    using Spire.Pdf.Graphics.Layer;
    using System.Drawing;
    
    namespace AddLayersToPdf
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance and load a sample PDF file
                PdfDocument pdf = new PdfDocument();
                pdf.LoadFromFile(@"C:\Users\Administrator\Desktop\Sample.pdf");
    
                //Invoke AddLayerWatermark method to add a watermark layer
                AddLayerWatermark(pdf);
    
                //Invoke AddLayerHeader method to add a header layer
                AddLayerHeader(pdf);
    
                //Save to file
                pdf.SaveToFile("AddLayers.pdf");
                pdf.Close();
            }
    
            private static void AddLayerWatermark(PdfDocument doc)
            {
                //Create a layer named "Watermark"
                PdfLayer layer = doc.Layers.AddLayer("Watermark");
    
                //Create a font
                PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 48), true);
    
                //Specify the watermark text
                string watermarkText = "CONFIDENTIAL";
    
                //Get text size
                SizeF fontSize = font.MeasureString(watermarkText);
    
                //Calculate two offsets
                float offset1 = (float)(fontSize.Width * System.Math.Sqrt(2) / 4);
                float offset2 = (float)(fontSize.Height * System.Math.Sqrt(2) / 4);
    
                //Get page count
                int pageCount = doc.Pages.Count;
    
                //Declare two variables
                PdfPageBase page;
                PdfCanvas canvas;
    
                //Loop through the pages
                for (int i = 0; (i < pageCount); i++)
                {
                    page = doc.Pages[i];
    
                    //Create a canvas from layer
                    canvas = layer.CreateGraphics(page.Canvas);
                    canvas.TranslateTransform(page.Canvas.Size.Width / 2 - offset1 - offset2, page.Canvas.Size.Height / 2 + offset1 - offset2);
                    canvas.SetTransparency(0.4f);
                    canvas.RotateTransform(-45);
    
                    //Draw sting on the canvas of layer
                    canvas.DrawString(watermarkText, font, PdfBrushes.DarkBlue, 0, 0);
                }
            }
            private static void AddLayerHeader(PdfDocument doc)
            {
                // Create a layer named "Header"
                PdfLayer layer = doc.Layers.AddLayer("Header");
    
                //Get page size
                SizeF size = doc.Pages[0].Size;
    
                //Specify the initial values of X and y
                float x = 90;
                float y = 40;
    
                //Get page count
                int pageCount = doc.Pages.Count;
    
                //Declare two variables
                PdfPageBase page;
                PdfCanvas canvas;
    
                //Loop through the pages
                for (int i = 0; (i < pageCount); i++)
                {
                    //Draw an image on the layer
                    PdfImage pdfImage = PdfImage.FromFile(@"C:\Users\Administrator\Desktop\img.jpg");
                    float width = pdfImage.Width;
                    float height = pdfImage.Height;
                    page = doc.Pages[i];
                    canvas = layer.CreateGraphics(page.Canvas);
                    canvas.DrawImage(pdfImage, x, y, width, height);
    
                    //Draw a line on the layer
                    PdfPen pen = new PdfPen(PdfBrushes.DarkGray, 2);
                    canvas.DrawLine(pen, x, (y + (height + 5)), (size.Width - x), (y + (height + 2)));
                }
            }
        }
    } 

Imports Spire.Pdf
    Imports Spire.Pdf.Graphics
    Imports Spire.Pdf.Graphics.Layer
    Imports System.Drawing
    
    Namespace AddLayersToPdf
        Class Program
            Private Shared Sub Main(ByVal args() As String)
    
                'Create a PdfDocument instance and load a sample PDF file
                Dim pdf As PdfDocument = New PdfDocument
                pdf.LoadFromFile("C:\Users\Administrator\Desktop\Sample.pdf")
    
                'Invoke AddLayerWatermark method to add a watermark layer
                Program.AddLayerWatermark(pdf)
    
                'Invoke AddLayerHeader method to add a header layer
                Program.AddLayerHeader(pdf)
    
                'Save to file
                pdf.SaveToFile("AddLayers.pdf")
                pdf.Close()
            End Sub
    
            Private Shared Sub AddLayerWatermark(ByVal doc As PdfDocument)
    
                'Create a layer named "Watermark"
                Dim layer As PdfLayer = doc.Layers.AddLayer("Watermark")
    
                'Create a font
                Dim font As PdfTrueTypeFont = New PdfTrueTypeFont(New Font("Arial", 48), True)
    
                'Specify the watermark text
                Dim watermarkText As String = "CONFIDENTIAL"
    
                'Get text size
                Dim fontSize As SizeF = font.MeasureString(watermarkText)
    
                'Calculate two offsets
                Dim offset1 As Single = CSng((fontSize.Width * System.Math.Sqrt(2) / 4))
                Dim offset2 As Single = CSng((fontSize.Height * System.Math.Sqrt(2) / 4))
    
                'Get page count
                Dim pageCount As Integer = doc.Pages.Count
    
                'Declare two variables
                Dim page As PdfPageBase
                Dim canvas As PdfCanvas
    
                'Loop through the pages
                Dim i As Integer = 0
                While (i < pageCount)
                    page = doc.Pages(i)
    
                    'Create a canvas from layer
                    canvas = layer.CreateGraphics(page.Canvas)
                    canvas.TranslateTransform(page.Canvas.Size.Width / 2 - offset1 - offset2, page.Canvas.Size.Height / 2 + offset1 - offset2)
                    canvas.SetTransparency(0.4F)
                    canvas.RotateTransform(-45)
    
                    'Draw sting on the canvas of layer
                    canvas.DrawString(watermarkText, font, PdfBrushes.DarkBlue, 0, 0)
                    i = (i + 1)
                    i += 1
                End While
            End Sub
    
            Private Shared Sub AddLayerHeader(ByVal doc As PdfDocument)
    
                ' Create a layer named "Header"
                Dim layer As PdfLayer = doc.Layers.AddLayer("Header")
    
                'Get page size
                Dim size As SizeF = doc.Pages(0).Size
    
                'Specify the initial values of X and y
                Dim x As Single = 90
                Dim y As Single = 40
    
                'Get page count
                Dim pageCount As Integer = doc.Pages.Count
    
                'Declare two variables
                Dim page As PdfPageBase
                Dim canvas As PdfCanvas
    
                'Loop through the pages
                Dim i As Integer = 0
                While (i < pageCount)
    
                    'Draw an image on the layer
                    Dim pdfImage As PdfImage = PdfImage.FromFile("C:\Users\Administrator\Desktop\img.jpg")
                    Dim width As Single = pdfImage.Width
                    Dim height As Single = pdfImage.Height
                    page = doc.Pages(i)
                    canvas = layer.CreateGraphics(page.Canvas)
                    canvas.DrawImage(pdfImage, x, y, width, height)
    
                    'Draw a line on the layer
                    Dim pen As PdfPen = New PdfPen(PdfBrushes.DarkGray, 2)
                    canvas.DrawLine(pen, x, (y + (height + 5)), (size.Width - x), (y + (height + 2)))
                    i += 1
                End While
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    using Spire.Pdf.Graphics.Layer;
    
    namespace HideLayer
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance
                PdfDocument pdf = new PdfDocument();
    
                //Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf");
    
                //Hide a specified layer by index
                pdf.Layers[0].Visibility = PdfVisibility.Off;
    
                //Hide a specified layer by name
                //pdf.Layers["Watermark"].Visibility = PdfVisibility.Off;
    
                //Save the result document
                pdf.SaveToFile("HideLayer.pdf");
            }
        }
    }

Imports Spire.Pdf
    Imports Spire.Pdf.Graphics.Layer
    
    Namespace HideLayer
        Class Program
            Private Shared Sub Main(ByVal args() As String)
    
                'Create a PdfDocument instance
                Dim pdf As PdfDocument = New PdfDocument
    
                'Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf")
    
                'Hide a specified layer by index
                pdf.Layers(0).Visibility = PdfVisibility.Off
    
                'Hide a specified layer by name
                'pdf.Layers["Watermark"].Visibility = PdfVisibility.Off;
    
                'Save the result document
                pdf.SaveToFile("HideLayer.pdf")
            End Sub
        End Class
    End Namespace

using Spire.Pdf;
    
    namespace DeleteLayer
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance
                PdfDocument pdf = new PdfDocument();
    
                //Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf");
    
                //Remove a layer by name
                pdf.Layers.RemoveLayer(("Watermark"));
    
                //Save the result document
                pdf.SaveToFile("DeleteLayer.pdf", FileFormat.PDF);
            }
        }
    }

Imports Spire.Pdf
    
    Namespace DeleteLayer
        Class Program
            Private Shared Sub Main(ByVal args() As String)
                'Create a PdfDocument instance
                Dim pdf As PdfDocument = New PdfDocument
    
                'Load a sample PDF document
                pdf.LoadFromFile("AddLayers.pdf")
    
                'Remove a layer by name
                pdf.Layers.RemoveLayer("Watermark")
    
                'Save the result document
                pdf.SaveToFile("DeleteLayer.pdf", FileFormat.PDF)
            End Sub
        End Class
    End Namespace