Knowledgebase (2417)
Children categories
Spire.PDF can help us draw different shapes in PDF document. We can use Spire.PDF to draw rectangles in PDF, draw circles in PDF, draw arcs in PDF and draw ellipses in PDF. Besides these shapes, we can also use Spire.PDF to draw some other special shapes such as Spiral and five-pointed stars.
Draw Five-Pointed Star in PDF
By using Spire.PDF, we can draw different stars in PDF document. The sample below is showing how to draw 6 types of different five-pointed star.
using Spire.Pdf;
using Spire.Pdf.Graphics;
using System;
using System.Drawing;
namespace FivePointedStar
{
class Program
{
private static void DrawStar(PdfPageBase page)
{
PdfDocument doc = new PdfDocument();
PdfPageBase page = doc.Pages.Add();
PointF[] points = new PointF[5];
for (int i = 0; i < points.Length; i++)
{
float x = (float)Math.Cos(i * 2 * Math.PI / 5);
float y = (float)Math.Sin(i * 2 * Math.PI / 5);
points[i] = new PointF(x, y);
}
PdfPath path = new PdfPath();
path.AddLine(points[2], points[0]);
path.AddLine(points[0], points[3]);
path.AddLine(points[3], points[1]);
path.AddLine(points[1], points[4]);
path.AddLine(points[4], points[2]);
//save graphics state
PdfDocument doc = new PdfDocument();
PdfPageBase page = doc.Pages.Add();
PdfGraphicsState state = page.Canvas.Save();
PdfPen pen = new PdfPen(Color.DeepSkyBlue, 0.02f);
PdfBrush brush1 = new PdfSolidBrush(Color.CadetBlue);
page.Canvas.ScaleTransform(50f, 50f);
page.Canvas.TranslateTransform(5f, 1.2f);
page.Canvas.DrawPath(pen, path);
page.Canvas.TranslateTransform(2f, 0f);
path.FillMode = PdfFillMode.Alternate;
page.Canvas.DrawPath(pen, brush1, path);
page.Canvas.TranslateTransform(2f, 0f);
path.FillMode = PdfFillMode.Winding;
page.Canvas.DrawPath(pen, brush1, path);
PdfLinearGradientBrush brush2
= new PdfLinearGradientBrush(new PointF(-2, 0), new PointF(2, 0), Color.Red, Color.Blue);
page.Canvas.TranslateTransform(-4f, 2f);
path.FillMode = PdfFillMode.Alternate;
page.Canvas.DrawPath(pen, brush2, path);
PdfRadialGradientBrush brush3
= new PdfRadialGradientBrush(new PointF(0f, 0f), 0f, new PointF(0f, 0f), 1f, Color.Red, Color.Blue);
page.Canvas.TranslateTransform(2f, 0f);
path.FillMode = PdfFillMode.Winding;
page.Canvas.DrawPath(pen, brush3, path);
PdfTilingBrush brush4 = new PdfTilingBrush(new RectangleF(0, 0, 4f, 4f));
brush4.Graphics.DrawRectangle(brush2, 0, 0, 4f, 4f);
page.Canvas.TranslateTransform(2f, 0f);
path.FillMode = PdfFillMode.Winding;
page.Canvas.DrawPath(pen, brush4, path);
//restor graphics
page.Canvas.Restore(state);
}
}
}
Imports Spire.Pdf
Imports Spire.Pdf.Graphics
Imports System.Drawing
Namespace FivePointedStar
Class Program
Private Shared Sub DrawStar(page As PdfPageBase)
Dim doc As New PdfDocument()
Dim page As PdfPageBase = doc.Pages.Add()
Dim points As PointF() = New PointF(4) {}
For i As Integer = 0 To points.Length - 1
Dim x As Single = CSng(Math.Cos(i * 2 * Math.PI / 5))
Dim y As Single = CSng(Math.Sin(i * 2 * Math.PI / 5))
points(i) = New PointF(x, y)
Next
Dim path As New PdfPath()
path.AddLine(points(2), points(0))
path.AddLine(points(0), points(3))
path.AddLine(points(3), points(1))
path.AddLine(points(1), points(4))
path.AddLine(points(4), points(2))
'save graphics state
Dim doc As New PdfDocument()
Dim page As PdfPageBase = doc.Pages.Add()
Dim state As PdfGraphicsState = page.Canvas.Save()
Dim pen As New PdfPen(Color.DeepSkyBlue, 0.02F)
Dim brush1 As PdfBrush = New PdfSolidBrush(Color.CadetBlue)
page.Canvas.ScaleTransform(50F, 50F)
page.Canvas.TranslateTransform(5F, 1.2F)
page.Canvas.DrawPath(pen, path)
page.Canvas.TranslateTransform(2F, 0F)
path.FillMode = PdfFillMode.Alternate
page.Canvas.DrawPath(pen, brush1, path)
page.Canvas.TranslateTransform(2F, 0F)
path.FillMode = PdfFillMode.Winding
page.Canvas.DrawPath(pen, brush1, path)
Dim brush2 As New PdfLinearGradientBrush(New PointF(-2, 0), New PointF(2, 0), Color.Red, Color.Blue)
page.Canvas.TranslateTransform(-4F, 2F)
path.FillMode = PdfFillMode.Alternate
page.Canvas.DrawPath(pen, brush2, path)
Dim brush3 As New PdfRadialGradientBrush(New PointF(0F, 0F), 0F, New PointF(0F, 0F), 1F, Color.Red, Color.Blue)
page.Canvas.TranslateTransform(2F, 0F)
path.FillMode = PdfFillMode.Winding
page.Canvas.DrawPath(pen, brush3, path)
Dim brush4 As New PdfTilingBrush(New RectangleF(0, 0, 4F, 4F))
brush4.Graphics.DrawRectangle(brush2, 0, 0, 4F, 4F)
page.Canvas.TranslateTransform(2F, 0F)
path.FillMode = PdfFillMode.Winding
page.Canvas.DrawPath(pen, brush4, path)
'restor graphics
page.Canvas.Restore(state)
End Sub
End Class
End Namespace
Effective Screenshot:
Draw Spiral in PDF
A spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point. Spire.PDF can also help us easily draw Spiral in PDF and we can design at will.
using Spire.Pdf;
using Spire.Pdf.Graphics;
using System;
namespace DrawSpiral
{
class Program
{
static void Main(string[] args)
{
PdfDocument doc = new PdfDocument();
PdfPageBase page = doc.Pages.Add();
//save graphics state
PdfGraphicsState state = page.Canvas.Save();
//Draw shap - spiro
PdfPen pen = PdfPens.DeepSkyBlue;
int nPoints = 1000;
double r1 = 30;
double r2 = 25;
double p = 35;
double x1 = r1 + r2 - p;
double y1 = 0;
double x2 = 0;
double y2 = 0;
page.Canvas.TranslateTransform(100, 100);
for (int i = 0; i < nPoints; i++)
{
double t = i * Math.PI / 90;
x2 = (r1 + r2) * Math.Cos(t) - p * Math.Cos((r1 + r2) * t / r2);
y2 = (r1 + r2) * Math.Sin(t) - p * Math.Sin((r1 + r2) * t / r2);
page.Canvas.DrawLine(pen, (float)x1, (float)y1, (float)x2, (float)y2);
x1 = x2;
y1 = y2;
}
//restor graphics
page.Canvas.Restore(state);
}
}
}
Imports Spire.Pdf
Imports Spire.Pdf.Graphics
Imports Spire.Pdf.Texts
Imports System.Drawing
Namespace AddLineNumber
Class Program
Shared Sub Main(ByVal args() As String)
Dim doc As New PdfDocument()
Dim page As PdfPageBase = doc.Pages.Add()
'save graphics state
Dim state As PdfGraphicsState = page.Canvas.Save()
'Draw shap - spiro
Dim pen As PdfPen = PdfPens.DeepSkyBlue
Dim nPoints As Integer = 1000
Dim r1 As Double = 30
Dim r2 As Double = 25
Dim p As Double = 35
Dim x1 As Double = r1 + r2 - p
Dim y1 As Double = 0
Dim x2 As Double = 0
Dim y2 As Double = 0
page.Canvas.TranslateTransform(100, 100)
For i As Integer = 0 To nPoints - 1
Dim t As Double = i * Math.PI / 90
x2 = (r1 + r2) * Math.Cos(t) - p * Math.Cos((r1 + r2) * t / r2)
y2 = (r1 + r2) * Math.Sin(t) - p * Math.Sin((r1 + r2) * t / r2)
page.Canvas.DrawLine(pen, CSng(x1), CSng(y1), CSng(x2), CSng(y2))
x1 = x2
y1 = y2
Next
'restor graphics
page.Canvas.Restore(state)
End Sub
End Class
End Namespace
Effective Screenshot:
In the realm of PDF creation and editing, the ability to draw different styles of text within a PDF can greatly enhance the visual appeal and functionality of the documents. For example, you can draw transformed text to add a unique touch to the document design, or draw rotated text to create angled headings. In this article, you will learn how to draw text in PDF with different styles in C# using Spire.PDF for .NET.
Install Spire.PDF for .NET
To begin with, you need to add the DLL files included in the Spire.PDF for.NET package as references in your .NET project. The DLL files can be either downloaded from this link or installed via NuGet.
PM> Install-Package Spire.PDF
Coordinate System in Spire.PDF
The text drawn in PDF is based on the page coordinate system. When adding a new page in a PDF, the page usually consists of the content area and margins all around.
In this case, the origin of the coordinate system is located at the top left corner of the content area, with the x-axis extending horizontally to the right and the y-axis extending vertically down.
Transformation of the Coordinate System
When transforming text in PDF, you are actually transforming the coordinate system where the text is located. Spire.PDF allows to translate, scale, skew, and rotate the page coordinate. The specific methods are introduced below:
- TranslateTransform(5, 5): Translate the coordinate system 5 units to the right and 5 units downward.
- ScaleTransform(2, 2): Scale the unit lengths on both the X-axis and the Y-axis by a factor of 2.
- RotateTransform(-45): Rotate the coordinate system 45 degrees counterclockwise.
- SkewTransform(10, 10): Tilt the X-axis 10 degrees down and the Y-axis 10 degrees to the right
By mastering this background knowledge about the page coordinate system, you can use Spire.PDF more accurately to draw different styles of text in PDFs to achieve complex typography.
Draw Transformed Text in PDF in C#
To accomplish the task, you can scale or skew the coordinate system of a PDF page through the PdfPageBase.Canvas.ScaleTransform() or PdfPageBase.Canvas.SkewTransform() method, and then draw text on the transformed coordinate system. The following are the detailed steps.
- Create a PdfDocument instance.
- Add a page using PdfDocument.Pages.Add() method.
- Save the current drawing state using PdfPageBase.Canvas.Save() method.
- Specify the PDF font and brush.
- Translate the page coordinate system to the specified position using PdfPageBase.Canvas.TranslateTransform() method .
- Scale the current coordinate system using PdfPageBase.Canvas.ScaleTransform() method .
- Skew the current coordinate system using PdfPageBase.Canvas.SkewTransform() method.
- Draw text on the page based on the transformed coordinate system using PdfPageBase.Canvas.DrawString() method.
- Restore the previous drawing state using PdfPageBase.Canvas.Restore(state) method.
- Save the result file using PdfDocument.SaveToFile() method.
- C#
using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;
namespace PDFText
{
class Program
{
static void Main(string[] args)
{
// Create a PdfDocument instance
PdfDocument pdf = new PdfDocument();
// Add a page
PdfPageBase page = pdf.Pages.Add();
// Save the current graphics state
PdfGraphicsState state = page.Canvas.Save();
// Specify the PDF font and brush
PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 18f);
PdfSolidBrush brush1 = new PdfSolidBrush(Color.Green);
PdfSolidBrush brush2 = new PdfSolidBrush(Color.Blue);
PdfSolidBrush brush3 = new PdfSolidBrush(Color.Magenta);
// Translate the coordinate system by specified coordinates
page.Canvas.TranslateTransform(20, 280);
// Scale the coordinate system by specified coordinates
page.Canvas.ScaleTransform(1f, 0.6f);
// Skew the coordinate system axes
page.Canvas.SkewTransform(-10, 0);
// Draw transformed text on the page
page.Canvas.DrawString("A Powerful PDF Processing Library", font, brush1, 0, -30);
// Skew the coordinate system axes
page.Canvas.SkewTransform(10, 0);
// Draw transformed text on the page
page.Canvas.DrawString("A Powerful PDF Processing Library", font, brush2, 0, 0);
//Scale the coordinate system by specified coordinates
page.Canvas.ScaleTransform(1f, -1f);
// Draw transformed text on the page
page.Canvas.DrawString("A Powerful PDF Processing Library", font, brush3, 0, 0);
// Restor graphics state
page.Canvas.Restore(state);
// Save the result document
pdf.SaveToFile("TransformText.pdf");
pdf.Close();
}
}
}
Draw Rotated Text in PDF in C#
The PdfPageBase.Canvas.RotateTransform(float angle) method provided by Spire.PDF allows to rotate the page coordinate system to specified angle, and then the text drawn on the page will be presented as rotated text. The following are the detailed steps.
- Create a PdfDocument instance.
- Add a page using PdfDocument.Pages.Add() method.
- Save the current drawing state using PdfPageBase.Canvas.Save() method.
- Specify the PDF font and brush, and set PDF text alignment.
- Translate the page coordinate system to the specified position using PdfPageBase.Canvas.TranslateTransform() method.
- Rotate the coordinate system by specified degree using PdfPageBase.Canvas.RotateTransform() method.
- Draw text on the page based on the rotated coordinate system using PdfPageBase.Canvas.DrawString() method.
- Restore the previous drawing state using PdfPageBase.Canvas.Restore(state) method.
- Save the result file using PdfDocument.SaveToFile() method.
- C#
using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;
namespace PDFText
{
class Program
{
static void Main(string[] args)
{
// Create a PdfDocument instance
PdfDocument pdf = new PdfDocument();
// Add a page
PdfPageBase page = pdf.Pages.Add();
// Save the current graphics state
PdfGraphicsState state = page.Canvas.Save();
// Specify the PDF font and brush
PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 12f);
PdfSolidBrush brush = new PdfSolidBrush(Color.Blue);
// Set PDF text alignment
PdfStringFormat centerAlignment = new PdfStringFormat(PdfTextAlignment.Left, PdfVerticalAlignment.Middle);
// Translate the coordinate system by specified coordinates
page.Canvas.TranslateTransform(page.Canvas.ClientSize.Width / 2, 380);
// Draw rotated text on the PDF page
for (int i = 0; i < 8; i++)
{
page.Canvas.RotateTransform(45);
page.Canvas.DrawString("A Powerful PDF Processing Library", font, brush, 20, 0, centerAlignment);
}
// Restor graphics state
page.Canvas.Restore(state);
// Save the result document
pdf.SaveToFile("RotateText.pdf");
pdf.Close();
}
}
}
Draw Aligned Text in PDF in C#
Spire.PDF for .NET provides the PdfStringFormat class to represent the text layout information. You can initialize an instance of the PdfStringFormat class and pass in two parameters PdfTextAlignment and PdfVerticalAlignment to specify a text alignment style, then draw text with the alignment style. The following are the detailed steps.
- Create a PdfDocument instance.
- Add a page using PdfDocument.Pages.Add() method.
- Save the current drawing state using PdfPageBase.Canvas.Save() method.
- Specify the PDF font and brush.
- Create a PdfStringFormat instance and pass in the PdfTextAlignment and PdfVerticalAlignment parameters to specify the text alignment style.
- Draw text with the specified alignment style on the PDF page using PdfPageBase.Canvas.DrawString() method.
- Save the result file using PdfDocument.SaveToFile() method.
- C#
using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;
namespace PDFText
{
class Program
{
static void Main(string[] args)
{
// Create a PdfDocument instance
PdfDocument pdf = new PdfDocument();
// Add a page
PdfPageBase page = pdf.Pages.Add();
// Specify the PDF font and brush
PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 14f);
PdfSolidBrush brush1 = new PdfSolidBrush(Color.Green);
PdfSolidBrush brush2 = new PdfSolidBrush(Color.Blue);
PdfSolidBrush brush3 = new PdfSolidBrush(Color.Magenta);
// Draw left-aligned text on the PDF page
PdfStringFormat leftAlignment = new PdfStringFormat(PdfTextAlignment.Left, PdfVerticalAlignment.Middle);
page.Canvas.DrawString("Left Align", font, brush1, 0, 60, leftAlignment);
// Draw right-aligned text on the PDF page
PdfStringFormat rightAlignment = new PdfStringFormat(PdfTextAlignment.Right, PdfVerticalAlignment.Middle);
page.Canvas.DrawString("Right Align", font, brush2, page.Canvas.ClientSize.Width, 60, rightAlignment);
// Draw center-aligned text on the PDF page
PdfStringFormat centerAlignment = new PdfStringFormat(PdfTextAlignment.Center, PdfVerticalAlignment.Middle);
page.Canvas.DrawString("Center Align", font, brush3, page.Canvas.ClientSize.Width / 2, 60, centerAlignment);
// Save the result document
pdf.SaveToFile("PdfTextAlignment.pdf");
pdf.Close();
}
}
}
Apply for a Temporary License
If you'd like to remove the evaluation message from the generated documents, or to get rid of the function limitations, please request a 30-day trial license for yourself.
Compared with text-only documents, documents containing images are undoubtedly more vivid and engaging to readers. When generating or editing a PDF document, you may sometimes need to insert images to improve its appearance and make it more appealing. In this article, you will learn how to insert, replace or delete images in PDF documents in C# and VB.NET using Spire.PDF for .NET.
- Insert an Image into a PDF Document
- Replace an Image with Another Image in a PDF Document
- Delete a Specific Image in a PDF Document
Install Spire.PDF for .NET
To begin with, you need to add the DLL files included in the Spire.PDF for.NET package as references in your .NET project. The DLL files can be either downloaded from this link or installed via NuGet.
PM> Install-Package Spire.PDF
Insert an Image into a PDF Document in C# and VB.NET
The following steps demonstrate how to insert an image into an existing PDF document:
- Initialize an instance of the PdfDocument class.
- Load a PDF document using PdfDocument.LoadFromFile() method.
- Get the desired page in the PDF document through PdfDocument.Pages[pageIndex] property.
- Load an image using PdfImage.FromFile() method.
- Specify the width and height of the image area on the page.
- Specify the X and Y coordinates to start drawing the image.
- Draw the image on the page using PdfPageBase.Canvas.DrawImage() method.
- Save the result document using PdfDocument.SaveToFile() method.
- C#
- VB.NET
using Spire.Pdf;
using Spire.Pdf.Graphics;
namespace InsertImage
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument instance
PdfDocument pdf = new PdfDocument();
pdf.LoadFromFile("Input.pdf");
//Get the first page in the PDF document
PdfPageBase page = pdf.Pages[0];
//Load an image
PdfImage image = PdfImage.FromFile("image.jpg");
//Specify the width and height of the image area on the page
float width = image.Width * 0.50f;
float height = image.Height * 0.50f;
//Specify the X and Y coordinates to start drawing the image
float x = 180f;
float y = 70f;
//Draw the image at a specified location on the page
page.Canvas.DrawImage(image, x, y, width, height);
//Save the result document
pdf.SaveToFile("AddImage.pdf", FileFormat.PDF);
}
}
}
Replace an Image with Another Image in a PDF Document in C# and VB.NET
The following steps demonstrate how to replace an image with another image in a PDF document:
- Initialize an instance of the PdfDocument class.
- Load a PDF document using PdfDocument.LoadFromFile() method.
- Get the desired page in the PDF document through PdfDocument.Pages[pageIndex] property.
- Load an image using PdfImage.FromFile() method.
- Initialize an instance of the PdfImageHelper class.
- Get the image information from the page using PdfImageHelper.GetImagesInfo() method.
- Replace a specific image on the page with the loaded image using PdfImageHelper.ReplaceImage() method.
- Save the result document using PdfDocument.SaveToFile() method.
- C#
- VB.NET
using Spire.Pdf;
using Spire.Pdf.Graphics;
using Spire.Pdf.Utilities;
namespace ReplaceImage
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument instance
PdfDocument doc = new PdfDocument();
//Load a PDF document
doc.LoadFromFile("AddImage.pdf");
//Get the first page
PdfPageBase page = doc.Pages[0];
//Load an image
PdfImage image = PdfImage.FromFile("image1.jpg");
//Create a PdfImageHelper instance
PdfImageHelper imageHelper = new PdfImageHelper();
//Get the image information from the page
PdfImageInfo[] imageInfo = imageHelper.GetImagesInfo(page);
//Replace the first image on the page with the loaded image
imageHelper.ReplaceImage(imageInfo[0], image);
//Save the result document
doc.SaveToFile("ReplaceImage.pdf", FileFormat.PDF);
}
}
}
Delete a Specific Image in a PDF Document in C# and VB.NET
The following steps demonstrate how to delete an image from a PDF document:
- Initialize an instance of the PdfDocument class.
- Load a PDF document using PdfDocument.LoadFromFile() method.
- Get the desired page in the PDF document through PdfDocument.Pages[pageIndex] property.
- Delete a specific image on the page using PdfPageBase.DeleteImage() method.
- Save the result document using PdfDocument.SaveToFile() method.
- C#
- VB.NET
using Spire.Pdf;
namespace DeleteImage
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument instance
PdfDocument pdf = new PdfDocument();
//Load a PDF document
pdf.LoadFromFile("AddImage.pdf");
//Get the first page
PdfPageBase page = pdf.Pages[0];
//Delete the first image on the page
PdfImageHelper imageHelper = new PdfImageHelper();
PdfImageInfo[] imageInfos = imageHelper.GetImagesInfo(pdf.Pages[0]);
for (int i = 0; i < imageInfos.Length; i++)
{ imageHelper.DeleteImage(imageInfos[i], true); }
//Save the result document
pdf.SaveToFile("DeleteImage.pdf", FileFormat.PDF);
}
}
}
Apply for a Temporary License
If you'd like to remove the evaluation message from the generated documents, or to get rid of the function limitations, please request a 30-day trial license for yourself.
