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Build, write, embed elements in PDF pages using C# (UWP)

Sample C# (UWP) code to use PDFTron SDK's page writing API to generate new pages, embed fonts & images, and copy graphical elements from one page to another. Learn more about our PDF Editing & Manipulation Library.

To run this sample, get started with a free trial of PDFTron SDK.

using System;
using System.IO;
using System.Threading.Tasks;
using Windows.Foundation;

using pdftron.Common;
using pdftron.Filters;
using pdftron.PDF;
using pdftron.SDF;

using PDFNetUniversalSamples.ViewModels;

namespace PDFNetSamples
{
    public sealed class ElementBuilderTest : Sample
    {
        public ElementBuilderTest() :
            base("ElementBuilder", "Illustrates how to use PDFNet page writing API, how to embed fonts and images and how to copy graphical elements from one page to another.")
        {
        }

        public override IAsyncAction RunAsync()
        {
            return Task.Run(new System.Action(async () => {
                WriteLine("--------------------------------");
                WriteLine("Starting ElementBuilder Test...");
                WriteLine("--------------------------------\n");
            
                try
                {
                    PDFDoc doc = new PDFDoc();

                    ElementBuilder eb = new ElementBuilder();		// ElementBuilder is used to build new Element objects
                    ElementWriter writer = new ElementWriter();	// ElementWriter is used to write Elements to the page	

                    // Start a new page ------------------------------------
                    // Position an image stream on several places on the page
                    pdftron.PDF.Page page = doc.PageCreate(new pdftron.PDF.Rect(0, 0, 612, 794));

                    writer.Begin(page);	// begin writing to this page

                    // Create an Image that can be reused multiple times in the document or 
                    // multiple on the same page.

                    MappedFile img_file = new MappedFile(Path.Combine(InputPath, "peppers.jpg"));
                    FilterReader img_data = new FilterReader(img_file);
                    pdftron.PDF.Image img = pdftron.PDF.Image.Create(new SDFDoc(doc), img_data, 400, 600, 8, ColorSpace.CreateDeviceRGB(), pdftron.PDF.ImageInputFilter.e_jpeg);

                    Element element = eb.CreateImage(img, new Matrix2D(200, -145, 20, 300, 200, 150));
                    writer.WritePlacedElement(element);

                    GState gstate = element.GetGState();	// use the same image (just change its matrix)
                    gstate.SetTransform(200, 0, 0, 300, 50, 450);
                    writer.WritePlacedElement(element);

                    // use the same image again (just change its matrix).
                    writer.WritePlacedElement(eb.CreateImage(img, 300, 600, 200, -150));
                
                    writer.End();  // save changes to the current page
                    doc.PagePushBack(page);

                    // Start a new page ------------------------------------
                    // Construct and draw a path object using different styles
                    page = doc.PageCreate(new pdftron.PDF.Rect(0, 0, 612, 794));

                    writer.Begin(page);	// begin writing to this page
                    eb.Reset(); 		// Reset GState to default

                    eb.PathBegin();		// start constructing the path				                            
                    eb.MoveTo(306, 396);
                    eb.CurveTo(681, 771, 399.75, 864.75, 306, 771);
                    eb.CurveTo(212.25, 864.75, -69, 771, 306, 396);
                    eb.ClosePath();
                    element = eb.PathEnd();			// the path is now finished
                    element.SetPathFill(true);		// the path should be filled

                    // Set the path color space and color
                    gstate = element.GetGState();
                    gstate.SetFillColorSpace(ColorSpace.CreateDeviceCMYK());
                    gstate.SetFillColor(new ColorPt(1, 0, 0, 0));  // cyan
                    gstate.SetTransform(0.5, 0, 0, 0.5, -20, 300);
                    writer.WritePlacedElement(element);

                    // Draw the same path using a different stroke color
                    element.SetPathStroke(true);		// this path is should be filled and stroked
                    gstate.SetFillColor(new ColorPt(0, 0, 1, 0));  // yellow
                    gstate.SetStrokeColorSpace(ColorSpace.CreateDeviceRGB());
                    gstate.SetStrokeColor(new ColorPt(1, 0, 0));  // red
                    gstate.SetTransform(0.5, 0, 0, 0.5, 280, 300);
                    gstate.SetLineWidth(20);
                    writer.WritePlacedElement(element);

                    // Draw the same path with with a given dash pattern
                    element.SetPathFill(false);	// this path is should be only stroked
                    gstate.SetStrokeColor(new ColorPt(0, 0, 1));  // blue
                    gstate.SetTransform(0.5, 0, 0, 0.5, 280, 0);
                    double[] dash_pattern = { 30 };
                    gstate.SetDashPattern(dash_pattern, 0);
                    writer.WritePlacedElement(element);

                    // Use the path as a clipping path
                    writer.WriteElement(eb.CreateGroupBegin());	// Save the graphics state
                    // Start constructing a new path (the old path was lost when we created 
                    // a new Element using CreateGroupBegin()).
                    eb.PathBegin();
                    eb.MoveTo(306, 396);
                    eb.CurveTo(681, 771, 399.75, 864.75, 306, 771);
                    eb.CurveTo(212.25, 864.75, -69, 771, 306, 396);
                    eb.ClosePath();
                    element = eb.PathEnd();	// path is now built
                    element.SetPathClip(true);	// this path is a clipping path
                    element.SetPathStroke(true);		// this path is should be filled and stroked
                    gstate = element.GetGState();
                    gstate.SetTransform(0.5, 0, 0, 0.5, -20, 0);
                    writer.WriteElement(element);
                    writer.WriteElement(eb.CreateImage(img, 100, 300, 400, 600));
                    writer.WriteElement(eb.CreateGroupEnd());	// Restore the graphics state

                    writer.End();  // save changes to the current page
                    doc.PagePushBack(page);

                    // Start a new page ------------------------------------
                    page = doc.PageCreate(new pdftron.PDF.Rect(0, 0, 612, 794));

                    writer.Begin(page);	// begin writing to this page
                    eb.Reset(); 		// Reset GState to default

                    // Begin writing a block of text
                    element = eb.CreateTextBegin(Font.Create(doc.GetSDFDoc(), FontStandardType1Font.e_times_roman), 12);
                    writer.WriteElement(element);

                    string data = "Hello World!";
                    element = eb.CreateTextRun(data);
                    element.SetTextMatrix(10, 0, 0, 10, 0, 600);
                    element.GetGState().SetLeading(15);		 // Set the spacing between lines
                    writer.WriteElement(element);

                    writer.WriteElement(eb.CreateTextNewLine());  // New line

                    element = eb.CreateTextRun(data);
                    gstate = element.GetGState();
                    gstate.SetTextRenderMode(GStateTextRenderingMode.e_stroke_text);
                    gstate.SetCharSpacing(-1.25);
                    gstate.SetWordSpacing(-1.25);
                    writer.WriteElement(element);

                    writer.WriteElement(eb.CreateTextNewLine());  // New line

                    element = eb.CreateTextRun(data);
                    gstate = element.GetGState();
                    gstate.SetCharSpacing(0);
                    gstate.SetWordSpacing(0);
                    gstate.SetLineWidth(3);
                    gstate.SetTextRenderMode(GStateTextRenderingMode.e_fill_stroke_text);
                    gstate.SetStrokeColorSpace(ColorSpace.CreateDeviceRGB());
                    gstate.SetStrokeColor(new ColorPt(1, 0, 0));	// red
                    gstate.SetFillColorSpace(ColorSpace.CreateDeviceCMYK());
                    gstate.SetFillColor(new ColorPt(1, 0, 0, 0));	// cyan
                    writer.WriteElement(element);

                    writer.WriteElement(eb.CreateTextNewLine());  // New line

                    // Set text as a clipping path to the image.
                    element = eb.CreateTextRun(data);
                    gstate = element.GetGState();
                    gstate.SetTextRenderMode(GStateTextRenderingMode.e_clip_text);
                    writer.WriteElement(element);

                    // Finish the block of text
                    writer.WriteElement(eb.CreateTextEnd());

                    // Draw an image that will be clipped by the above text
                    writer.WriteElement(eb.CreateImage(img, 10, 100, 1300, 720));

                    writer.End();  // save changes to the current page
                    doc.PagePushBack(page);

                    // Start a new page ------------------------------------
                    //
                    // The example illustrates how to embed the external font in a PDF document. 
                    // The example also shows how ElementReader can be used to copy and modify 
                    // Elements between pages.

                    ElementReader reader = new ElementReader();

                    // Start reading Elements from the last page. We will copy all Elements to 
                    // a new page but will modify the font associated with text.
                    reader.Begin(doc.GetPage(doc.GetPageCount()));

                    page = doc.PageCreate(new pdftron.PDF.Rect(0, 0, 1300, 794));

                    writer.Begin(page);	// begin writing to this page
                    eb.Reset(); 		// Reset GState to default

                    // Embed an external font in the document.
                    Font font = Font.CreateTrueTypeFont(doc, Path.Combine(InputPath, "font.ttf"));

                    while ((element = reader.Next()) != null) 	// Read page contents
                    {
                        if (element.GetType() == ElementType.e_text)
                        {
                            element.GetGState().SetFont(font, 12);
                        }

                        writer.WriteElement(element);
                    }

                    reader.End();
                    writer.End();  // save changes to the current page

                    doc.PagePushBack(page);

                    // Start a new page ------------------------------------
                    //
                    // The example illustrates how to embed the external font in a PDF document. 
                    // The example also shows how ElementReader can be used to copy and modify 
                    // Elements between pages.

                    // Start reading Elements from the last page. We will copy all Elements to 
                    // a new page but will modify the font associated with text.
                    reader.Begin(doc.GetPage(doc.GetPageCount()));

                    page = doc.PageCreate(new pdftron.PDF.Rect(0, 0, 1300, 794));

                    writer.Begin(page);	// begin writing to this page
                    eb.Reset(); 		// Reset GState to default

                    // Embed an external font in the document.
                    Font font2 = Font.CreateType1Font(doc, Path.Combine(InputPath, "Misc-Fixed.pfa"));

                    while ((element = reader.Next()) != null) 	// Read page contents
                    {
                        if (element.GetType() == ElementType.e_text)
                        {
                            element.GetGState().SetFont(font2, 12);
                        }
                        writer.WriteElement(element);
                    }

                    reader.End();
                    writer.End();  // save changes to the current page
                    doc.PagePushBack(page);


                    // Start a new page ------------------------------------
                    page = doc.PageCreate();
                    writer.Begin(page);	// begin writing to this page
                    eb.Reset(); 		// Reset GState to default

                    // Begin writing a block of text
                    //System.Drawing.Font sys_font = new System.Drawing.Font("Comic Sans MS", 12);
                    //Font my_font = Font.CreateTrueTypeFont(doc, sys_font, false, false);
                    Font my_font = Font.Create(doc, pdftron.PDF.FontStandardType1Font.e_times_roman);
                    element = eb.CreateTextBegin(my_font, 12);
                    element.SetTextMatrix(1.5, 0, 0, 1.5, 50, 600);
                    element.GetGState().SetLeading(15);	// Set the spacing between lines
                    writer.WriteElement(element);

                    string para = "A PDF text object consists of operators that can show " +
                    "text strings, move the text position, and set text state and certain " +
                    "other parameters. In addition, there are three parameters that are " +
                    "defined only within a text object and do not persist from one text " +
                    "object to the next: Tm, the text matrix, Tlm, the text line matrix, " +
                    "Trm, the text rendering matrix, actually just an intermediate result " +
                    "that combines the effects of text state parameters, the text matrix " +
                    "(Tm), and the current transformation matrix";

                    int para_end = para.Length;
                    int text_run = 0;
                    int text_run_end;

                    double para_width = 300; // paragraph width is 300 units
                    double cur_width = 0;

                    while (text_run < para_end)
                    {
                        text_run_end = para.IndexOf(' ', text_run);
                        if (text_run_end < 0)
                            text_run_end = para_end - 1;

                        string text = para.Substring(text_run, text_run_end - text_run + 1);
                        element = eb.CreateTextRun(text);
                        if (cur_width + element.GetTextLength() < para_width)
                        {
                            writer.WriteElement(element);
                            cur_width += element.GetTextLength();
                        }
                        else
                        {
                            writer.WriteElement(eb.CreateTextNewLine());  // New line
                            text = para.Substring(text_run, text_run_end - text_run + 1);
                            element = eb.CreateTextRun(text);
                            cur_width = element.GetTextLength();
                            writer.WriteElement(element);
                        }

                        text_run = text_run_end + 1;
                    }

                    // Draw the same strings using direct content output...
                    writer.Flush();  // flush pending Element writing operations.

                    // You can also write page content directly to the content stream using 
                    // ElementWriter.WriteString(...) and ElementWriter.WriteBuffer(...) methods.
                    // Note that if you are planning to use these functions you need to be familiar
                    // with PDF page content operators (see Appendix A in PDF Reference Manual). 
                    // Because it is easy to make mistakes during direct output we recommend that 
                    // you use ElementBuilder and Element interface instead.
                    writer.WriteString("T* T* T* "); // New Lines 
                    writer.WriteElement(eb.CreateTextNewLine());
                    writer.WriteString("(Direct output to PDF page content stream:) Tj  T* ");
                    writer.WriteString("(AWAY) Tj T* ");
                    writer.WriteString("[(A)140(W)140(A)115(Y again)] TJ ");

                    // Finish the block of text
                    writer.WriteElement(eb.CreateTextEnd());

                    writer.End();  // save changes to the current page
                    doc.PagePushBack(page);


                    // Transparency sample ----------------------------------

                    // Start a new page -------------------------------------
                    page = doc.PageCreate();
                    writer.Begin(page);	// begin writing to this page
                    eb.Reset();			// Reset the GState to default

                    // Write some transparent text at the bottom of the page.
                    element = eb.CreateTextBegin(Font.Create(doc.GetSDFDoc(), FontStandardType1Font.e_times_roman), 100);

                    // Set the text knockout attribute. Text knockout must be set outside of 
                    // the text group.
                    gstate = element.GetGState();
                    gstate.SetTextKnockout(false);
                    gstate.SetBlendMode(GStateBlendMode.e_bl_difference);
                    writer.WriteElement(element);

                    element = eb.CreateTextRun("Transparency");
                    element.SetTextMatrix(1, 0, 0, 1, 30, 30);
                    gstate = element.GetGState();
                    gstate.SetFillColorSpace(ColorSpace.CreateDeviceCMYK());
                    gstate.SetFillColor(new ColorPt(1, 0, 0, 0));

                    gstate.SetFillOpacity(0.5);
                    writer.WriteElement(element);

                    // Write the same text on top the old; shifted by 3 points
                    element.SetTextMatrix(1, 0, 0, 1, 33, 33);
                    gstate.SetFillColor(new ColorPt(0, 1, 0, 0));
                    gstate.SetFillOpacity(0.5);

                    writer.WriteElement(element);
                    writer.WriteElement(eb.CreateTextEnd());

                    // Draw three overlapping transparent circles.
                    eb.PathBegin();		// start constructing the path
                    eb.MoveTo(459.223, 505.646);
                    eb.CurveTo(459.223, 415.841, 389.85, 343.04, 304.273, 343.04);
                    eb.CurveTo(218.697, 343.04, 149.324, 415.841, 149.324, 505.646);
                    eb.CurveTo(149.324, 595.45, 218.697, 668.25, 304.273, 668.25);
                    eb.CurveTo(389.85, 668.25, 459.223, 595.45, 459.223, 505.646);
                    element = eb.PathEnd();
                    element.SetPathFill(true);

                    gstate = element.GetGState();
                    gstate.SetFillColorSpace(ColorSpace.CreateDeviceRGB());
                    gstate.SetFillColor(new ColorPt(0, 0, 1));                     // Blue Circle

                    gstate.SetBlendMode(GStateBlendMode.e_bl_normal);
                    gstate.SetFillOpacity(0.5);
                    writer.WriteElement(element);

                    // Translate relative to the Blue Circle
                    gstate.SetTransform(1, 0, 0, 1, 113, -185);
                    gstate.SetFillColor(new ColorPt(0, 1, 0));                     // Green Circle
                    gstate.SetFillOpacity(0.5);
                    writer.WriteElement(element);

                    // Translate relative to the Green Circle
                    gstate.SetTransform(1, 0, 0, 1, -220, 0);
                    gstate.SetFillColor(new ColorPt(1, 0, 0));                     // Red Circle
                    gstate.SetFillOpacity(0.5);
                    writer.WriteElement(element);

                    writer.End();  // save changes to the current page
                    doc.PagePushBack(page);

                    // End page ------------------------------------

                    String output_file_path = Path.Combine(OutputPath, "element_builder.pdf");
                    await doc.SaveAsync(output_file_path, SDFDocSaveOptions.e_remove_unused);
                    doc.Destroy();
                    WriteLine("Done. Result saved in " + output_file_path);
                    await AddFileToOutputList(output_file_path).ConfigureAwait(false);
                }
                catch (Exception e)
                {
                    WriteLine(GetExceptionMessage(e));
                }

                WriteLine("\n--------------------------------");
                WriteLine("Done ElementBuilder Test.");
                WriteLine("--------------------------------\n");
            })).AsAsyncAction();
        }
    }
}
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