The sample shows the different modes of transparency.

Download Transparency.pdf

using System;
using System.Drawing;
using Spire.Pdf;
using Spire.Pdf.Graphics;

namespace Transparency
{
    class Program
    {
        static void Main(string[] args)
        {

            //Create a pdf document.
            PdfDocument doc = new PdfDocument();

            // Create one section
            PdfSection section = doc.Sections.Add();

            //Load image
            PdfImage image = PdfImage.FromFile("SalesReportChart.png");
            float imageWidth = image.PhysicalDimension.Width / 2;
            float imageHeight = image.PhysicalDimension.Height / 2;
            foreach (PdfBlendMode mode in Enum.GetValues(typeof(PdfBlendMode)))
            {
                PdfPageBase page = section.Pages.Add();
                float pageWidth = page.Canvas.ClientSize.Width;
                float y = 0;

                //title
                y = y + 5;
                PdfBrush brush = new PdfSolidBrush(Color.OrangeRed);
                PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 12f, FontStyle.Bold));
                PdfStringFormat format = new PdfStringFormat(PdfTextAlignment.Center);
                String text = String.Format("Transparency Blend Mode: {0}", mode);
                page.Canvas.DrawString(text, font, brush, pageWidth / 2, y, format);
                SizeF size = font.MeasureString(text, format);
                y = y + size.Height + 6;

                page.Canvas.DrawImage(image, 0, y, imageWidth, imageHeight);
                page.Canvas.Save();
                float d = (page.Canvas.ClientSize.Width - imageWidth) / 5;
                float x = d;
                y = y + d / 2;
                for (int i = 0; i < 5; i++)
                {
                    float alpha = 1.0f / 6 * (5 - i);
                    page.Canvas.SetTransparency(alpha, alpha, mode);
                    page.Canvas.DrawImage(image, x, y, imageWidth, imageHeight);
                    x = x + d;
                    y = y + d / 2;
                }
                page.Canvas.Restore();
            }

            //Save pdf file.
            doc.SaveToFile("Transparency.pdf");
            doc.Close();

            //Launching the Pdf file.
            System.Diagnostics.Process.Start("Transparency.pdf");
        }
    }
}

Imports System.Drawing
Imports Spire.Pdf
Imports Spire.Pdf.Graphics

Namespace Transparency
    Friend Class Program
        Shared Sub Main(ByVal args() As String)

            'Create a pdf document.
            Dim doc As New PdfDocument()

            ' Create one section
            Dim section As PdfSection = doc.Sections.Add()

            'Load image
            Dim image As PdfImage = PdfImage.FromFile("SalesReportChart.png")
            Dim imageWidth As Single = image.PhysicalDimension.Width \ 2
            Dim imageHeight As Single = image.PhysicalDimension.Height \ 2
            For Each mode As PdfBlendMode In System.Enum.GetValues(GetType(PdfBlendMode))
                Dim page As PdfPageBase = section.Pages.Add()
                Dim pageWidth As Single = page.Canvas.ClientSize.Width
                Dim y As Single = 0

                'title
                y = y + 5
                Dim brush As PdfBrush = New PdfSolidBrush(Color.OrangeRed)
                Dim font As New PdfTrueTypeFont(New Font("Arial", 12.0F, FontStyle.Bold))
                Dim format As New PdfStringFormat(PdfTextAlignment.Center)
                Dim text As String = String.Format("Transparency Blend Mode: {0}", mode)
                page.Canvas.DrawString(text, font, brush, pageWidth / 2, y, format)
                Dim size As SizeF = font.MeasureString(text, format)
                y = y + size.Height + 6

                page.Canvas.DrawImage(image, 0, y, imageWidth, imageHeight)
                page.Canvas.Save()
                Dim d As Single = (page.Canvas.ClientSize.Width - imageWidth) / 5
                Dim x As Single = d
                y = y + d / 2
                For i As Integer = 0 To 4
                    Dim alpha As Single = 1.0F / 6 * (5 - i)
                    page.Canvas.SetTransparency(alpha, alpha, mode)
                    page.Canvas.DrawImage(image, x, y, imageWidth, imageHeight)
                    x = x + d
                    y = y + d / 2
                Next i
                page.Canvas.Restore()
            Next mode

            'Save pdf file.
            doc.SaveToFile("Transparency.pdf")
            doc.Close()

            'Launching the Pdf file.
            Process.Start("Transparency.pdf")
        End Sub
    End Class
End Namespace

The sample demonstrates how to draw image in PDF document.

Download DrawImage.pdf

using System;
using System.Drawing;
using Spire.Pdf;
using Spire.Pdf.Graphics;

namespace DrawImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a pdf document.
            PdfDocument doc = new PdfDocument();

            // Create one page
            PdfPageBase page = doc.Pages.Add();

            TransformText(page);
            DrawImage(page);
            TransformImage(page);

            //Save pdf file.
            doc.SaveToFile("DrawImage.pdf");
            doc.Close();

            //Launching the Pdf file.
            System.Diagnostics.Process.Start("DrawImage.pdf");
        }

        private static void TransformImage(PdfPageBase page)
        {
            //save graphics state
            PdfGraphicsState state = page.Canvas.Save();

            //Draw the text - transform           
            PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 18f);
            PdfSolidBrush brush1 = new PdfSolidBrush(Color.Blue);
            PdfSolidBrush brush2 = new PdfSolidBrush(Color.CadetBlue);
            PdfStringFormat format = new PdfStringFormat(PdfTextAlignment.Center);

            page.Canvas.TranslateTransform(page.Canvas.ClientSize.Width / 2, 20);
            page.Canvas.DrawString("Sales Report Chart", font, brush1, 0, 0, format);

            page.Canvas.ScaleTransform(1f, -0.8f);
            page.Canvas.DrawString("Sales Report Chart", font, brush2, 0, -2 * 18 * 1.2f, format);
            //restor graphics
            page.Canvas.Restore(state);
        }

        private static void DrawImage(PdfPageBase page)
        {
            PdfImage image = PdfImage.FromFile(@"SalesReportChart.png");
            float width = image.Width * 0.75f;
            float height = image.Height * 0.75f;
            float x = (page.Canvas.ClientSize.Width - width) / 2;

            page.Canvas.DrawImage(image, x, 60, width, height);
        }

        private static void TransformText(PdfPageBase page)
        {
            PdfImage image = PdfImage.FromFile(@"SalesReportChart.png");
            int skewX = 20;
            int skewY = 20;
            float scaleX = 0.2f;
            float scaleY = 0.6f;
            int width = (int)((image.Width + image.Height * Math.Tan(Math.PI * skewX / 180)) * scaleX);
            int height = (int)((image.Height + image.Width * Math.Tan(Math.PI * skewY / 180)) * scaleY);
            PdfTemplate template = new PdfTemplate(width, height);
            template.Graphics.ScaleTransform(scaleX, scaleY);
            template.Graphics.SkewTransform(skewX, skewY);
            template.Graphics.DrawImage(image, 0, 0);

            //save graphics state
            PdfGraphicsState state = page.Canvas.Save();
            page.Canvas.TranslateTransform(page.Canvas.ClientSize.Width - 50, 260);
            float offset = (page.Canvas.ClientSize.Width - 100) / 12;
            for (int i = 0; i < 12; i++)
            {
                page.Canvas.TranslateTransform(-offset, 0);
                page.Canvas.SetTransparency(i / 12.0f);
                page.Canvas.DrawTemplate(template, new PointF(0, 0));
            }

            //restor graphics
            page.Canvas.Restore(state);
        }
    }
}

Imports System.Drawing
Imports Spire.Pdf
Imports Spire.Pdf.Graphics

Namespace DrawImage
    Friend Class Program
        Shared Sub Main(ByVal args() As String)
            'Create a pdf document.
            Dim doc As New PdfDocument()

            ' Create one page
            Dim page As PdfPageBase = doc.Pages.Add()

            TransformText(page)
            DrawImage(page)
            TransformImage(page)

            'Save pdf file.
            doc.SaveToFile("DrawImage.pdf")
            doc.Close()

            'Launching the Pdf file.
            Process.Start("DrawImage.pdf")
        End Sub

        Private Shared Sub TransformImage(ByVal page As PdfPageBase)
            'save graphics state
            Dim state As PdfGraphicsState = page.Canvas.Save()

            'Draw the text - transform           
            Dim font As New PdfFont(PdfFontFamily.Helvetica, 18.0F)
            Dim brush1 As New PdfSolidBrush(Color.Blue)
            Dim brush2 As New PdfSolidBrush(Color.CadetBlue)
            Dim format As New PdfStringFormat(PdfTextAlignment.Center)

            page.Canvas.TranslateTransform(page.Canvas.ClientSize.Width \ 2, 20)
            page.Canvas.DrawString("Sales Report Chart", font, brush1, 0, 0, format)

            page.Canvas.ScaleTransform(1.0F, -0.8F)
            page.Canvas.DrawString("Sales Report Chart", font, brush2, 0, -2 * 18 * 1.2F, format)
            'restor graphics
            page.Canvas.Restore(state)
        End Sub

        Private Shared Sub DrawImage(ByVal page As PdfPageBase)
            Dim image As PdfImage = PdfImage.FromFile("SalesReportChart.png")
            Dim width As Single = image.Width * 0.75F
            Dim height As Single = image.Height * 0.75F
            Dim x As Single = (page.Canvas.ClientSize.Width - width) / 2

            page.Canvas.DrawImage(image, x, 60, width, height)
        End Sub

        Private Shared Sub TransformText(ByVal page As PdfPageBase)
            Dim image As PdfImage = PdfImage.FromFile("SalesReportChart.png")
            Dim skewX As Integer = 20
            Dim skewY As Integer = 20
            Dim scaleX As Single = 0.2F
            Dim scaleY As Single = 0.6F
            Dim width As Integer = CInt(Fix((image.Width + image.Height * Math.Tan(Math.PI * skewX \ 180)) * scaleX))
            Dim height As Integer = CInt(Fix((image.Height + image.Width * Math.Tan(Math.PI * skewY \ 180)) * scaleY))
            Dim template As New PdfTemplate(width, height)
            template.Graphics.ScaleTransform(scaleX, scaleY)
            template.Graphics.SkewTransform(skewX, skewY)
            template.Graphics.DrawImage(image, 0, 0)

            'save graphics state
            Dim state As PdfGraphicsState = page.Canvas.Save()
            page.Canvas.TranslateTransform(page.Canvas.ClientSize.Width - 50, 260)
            Dim offset As Single = (page.Canvas.ClientSize.Width - 100) / 12
            For i As Integer = 0 To 11
                page.Canvas.TranslateTransform(-offset, 0)
                page.Canvas.SetTransparency(i / 12.0F)
                page.Canvas.DrawTemplate(template, New PointF(0, 0))
            Next i

            'restor graphics
            page.Canvas.Restore(state)
        End Sub
    End Class
End Namespace