How to: Create Graphics in a PDF File with Landscape and Portrait Page Orientations

• Sep 19, 2023
• 3 minutes to read

Important

You need a license for the DevExpress Office File API Subscription or DevExpress Universal Subscription to use these examples in production code.

This example shows how to add text to the top left and bottom right of a page in a document with landscape and portrait pages.

PDF graphics are represented by an instance of the PdfGraphics class. To create graphics, call the PdfDocumentProcessor.CreateGraphics method. To access PdfGraphics, you need to reference the DevExpress.Pdf.Drawing assembly.

To rotate text that should be drawn in a document with landscape and portrait pages, call the PdfGraphics.RotateTransform method.

To move rotated text to desired position (bottom right) on a page, call the PdfGraphics.TranslateTransform method.

To draw text on a page, call the PdfGraphics.DrawString method with the specified text, font, brush and location.

To add graphics to a page foreground, call the PdfGraphics.AddToPageForeground method.

View Example

Program.cs

using System.Drawing;
using System.Collections.Generic;
using DevExpress.Pdf;

const float DrawingDpi = 72f;

static void Main(string[] args)
{
    using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
    {
        processor.LoadDocument("..\\..\\RotatedDocument.pdf");
        using (SolidBrush textBrush = new SolidBrush(Color.FromArgb(100, Color.Blue)))
            AddGraphics(processor, "text", textBrush);
        processor.SaveDocument("..\\..\\RotatedDocumentWithGraphics.pdf");
    }
}

static void AddGraphics(PdfDocumentProcessor processor, string text, SolidBrush textBrush)
{
    IList<PdfPage> pages = processor.Document.Pages;
    for (int i = 0; i < pages.Count; i++) {
        PdfPage page = pages[i];
        using (PdfGraphics graphics = processor.CreateGraphics())
        {
            SizeF actualPageSize = PrepareGraphics(page, graphics, DrawingDpi, DrawingDpi);
            using (Font font = new Font("Segoe UI", 20, FontStyle.Regular))
            {
                SizeF textSize =
                    graphics.MeasureString(text, font, PdfStringFormat.GenericDefault);
                PointF topLeft = new PointF(0, 0);
                PointF bottomRight =
                    new PointF(actualPageSize.Width - textSize.Width, actualPageSize.Height - textSize.Height);
                graphics.DrawString(text, font, textBrush, topLeft);
                graphics.DrawString(text, font, textBrush, bottomRight);
                graphics.AddToPageForeground(page, DrawingDpi, DrawingDpi);
            }
        }
    }
}

static SizeF PrepareGraphics(PdfPage page, PdfGraphics graphics, float dpiX, float dpiY) {
    PdfRectangle cropBox = page.CropBox;
    float cropBoxWidth = ConvertFromPdfUnits((float)cropBox.Width, dpiX);
    float cropBoxHeight = ConvertFromPdfUnits((float)cropBox.Height, dpiY);
    switch(page.Rotate) {
        case 90:
            graphics.RotateTransform(-90);
            graphics.TranslateTransform(-cropBoxHeight, 0);
            return new SizeF(cropBoxHeight, cropBoxWidth);
        case 180:
            graphics.RotateTransform(-180);
            graphics.TranslateTransform(-cropBoxWidth, -cropBoxHeight);
            return new SizeF(cropBoxWidth, cropBoxHeight);
        case 270:
            graphics.RotateTransform(-270);
            graphics.TranslateTransform(0, -cropBoxWidth);
            return new SizeF(cropBoxHeight, cropBoxWidth);
    }
    return new SizeF(cropBoxWidth, cropBoxHeight);
}

static float ConvertFromPdfUnits(float pdfValue, float targetDpi) {
    return pdfValue / 72f * targetDpi;
}

Program.vb

Imports System.Drawing
Imports System.Collections.Generic
Imports DevExpress.Pdf

Private Const DrawingDpi As Single = 72F

Shared Sub Main(ByVal args() As String)
    Using processor As New PdfDocumentProcessor()
        processor.LoadDocument("..\..\RotatedDocument.pdf")
        Using textBrush As New SolidBrush(Color.FromArgb(100, Color.Blue))
            AddGraphics(processor, "text", textBrush)
        End Using
        processor.SaveDocument("..\..\RotatedDocumentWithGraphics.pdf")
    End Using
End Sub

Shared Sub AddGraphics(ByVal processor As PdfDocumentProcessor, ByVal text As String, ByVal textBrush As SolidBrush)
    Dim pages As IList(Of PdfPage) = processor.Document.Pages
    For i As Integer = 0 To pages.Count - 1
        Dim page As PdfPage = pages(i)
        Using graphics As PdfGraphics = processor.CreateGraphics()
            Dim actualPageSize As SizeF = PrepareGraphics(page, graphics, DrawingDpi, DrawingDpi)
            Using font As New Font("Segoe UI", 20, FontStyle.Regular)
                Dim textSize As SizeF = graphics.MeasureString(text, font, PdfStringFormat.GenericDefault)
                Dim topLeft As New PointF(0, 0)
                Dim bottomRight As New PointF(actualPageSize.Width - textSize.Width, actualPageSize.Height - textSize.Height)
                graphics.DrawString(text, font, textBrush, topLeft)
                graphics.DrawString(text, font, textBrush, bottomRight)
                graphics.AddToPageForeground(page, DrawingDpi, DrawingDpi)
            End Using
        End Using
    Next i
End Sub

Shared Function PrepareGraphics(ByVal page As PdfPage, ByVal graphics As PdfGraphics, ByVal dpiX As Single, ByVal dpiY As Single) As SizeF
    Dim cropBox As PdfRectangle = page.CropBox
    Dim cropBoxWidth As Single = ConvertFromPdfUnits(CSng(cropBox.Width), dpiX)
    Dim cropBoxHeight As Single = ConvertFromPdfUnits(CSng(cropBox.Height), dpiY)
    Select Case page.Rotate
        Case 90
            graphics.RotateTransform(-90)
            graphics.TranslateTransform(-cropBoxHeight, 0)
            Return New SizeF(cropBoxHeight, cropBoxWidth)
        Case 180
            graphics.RotateTransform(-180)
            graphics.TranslateTransform(-cropBoxWidth, -cropBoxHeight)
            Return New SizeF(cropBoxWidth, cropBoxHeight)
        Case 270
            graphics.RotateTransform(-270)
            graphics.TranslateTransform(0, -cropBoxWidth)
            Return New SizeF(cropBoxHeight, cropBoxWidth)
    End Select
    Return New SizeF(cropBoxWidth, cropBoxHeight)
End Function

Shared Function ConvertFromPdfUnits(ByVal pdfValue As Single, ByVal targetDpi As Single) As Single
    Return pdfValue / 72F * targetDpi
End Function