Wednesday, 06 July 2011 03:26

Draw Circles in PDF in C#, VB.NET

Circles can be defined as the curves traced out by points that move so that its distance from a given point is constant. They are also look as special ellipses in which the two foci are coincident and the eccentricity is “0”. Whatever they are, they are indispensable in PDF document. This section will introduce a solution to draw circles and set their size and position in PDF file via a .NET PDF component Spire.PDF for .NET in C#, VB.NET.

When we draw circles in PDF, we only need to call one method in Spire.PDF: Spire.Pdf.PdfPageBase.Canvas.DrawPie(PdfPen pen, float x, float y, float width, float height, float startAngle, float sweepAngle); Here there are seven parameters in this method. The first one is the class Spire.Pdf.Graphics.PdfPen which can define the color and the outline of the circle. If we change this parameter to be another class Spire.Pdf.Graphics.PdfBrush, we can easily fill the circle with a certain color. The second and third parameters determine the exact distance between the PDF margin and the circle. "float x" decides the distance of left margin with circle, while "float y" means the distance between the top margin with the circle. By setting the fourth and fifth parameters, we can decide the circle width and height. The last two parameters are the start angle and sweep angle when drawing circles. Now please view the circles in PDF as below picture:

Draw Circles in PDF

Here we can quickly download Spire.PDF for .NET . After adding Spire.Pdf dll in the download Bin folder, we can draw circles in PDF file via Spire.PDF by below code.

[C#]
using System.Drawing;
using Spire.Pdf;
using Spire.Pdf.Graphics;

namespace pdf_circles
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a pdf document.
            PdfDocument doc = new PdfDocument();
            // Create one page
            PdfPageBase page = doc.Pages.Add();
            //save graphics state
            PdfGraphicsState state = page.Canvas.Save();
            PdfPen pen = new PdfPen(Color.Red, 1f);
            PdfPen pen1 = new PdfPen(Color.GreenYellow, 2f);
            PdfBrush brush = new PdfSolidBrush(Color.DeepSkyBlue);
            page.Canvas.DrawPie(pen, 30, 30, 80, 90, 360, 360);
            page.Canvas.DrawPie(brush, 150, 30, 100, 90, 360, 360);
            page.Canvas.DrawPie(pen1,290, 30, 70, 90, 360, 360);
            //restor graphics
            page.Canvas.Restore(state);
            doc.SaveToFile("Circles.pdf");
            System.Diagnostics.Process.Start("Circles.pdf");
        }
    }
}
[VB.NET]
Imports System.Drawing
Imports Spire.Pdf
Imports Spire.Pdf.Graphics

Namespace pdf_circles
	Class Program
		Private Shared Sub Main(args As String())
			'Create a pdf document.
			Dim doc As New PdfDocument()
			' Create one page
			Dim page As PdfPageBase = doc.Pages.Add()
			'save graphics state
			Dim state As PdfGraphicsState = page.Canvas.Save()
			Dim pen As New PdfPen(Color.Red, 1F)
			Dim pen1 As New PdfPen(Color.GreenYellow, 2F)
			Dim brush As PdfBrush = New PdfSolidBrush(Color.DeepSkyBlue)
			page.Canvas.DrawPie(pen, 30, 30, 80, 90, 360, _
				360)
			page.Canvas.DrawPie(brush, 150, 30, 100, 90, 360, _
				360)
			page.Canvas.DrawPie(pen1, 290, 30, 70, 90, 360, _
				360)
			'restor graphics
			page.Canvas.Restore(state)
			doc.SaveToFile("Circles.pdf")
			System.Diagnostics.Process.Start("Circles.pdf")
		End Sub
	End Class
End Namespace

Spire.PDF for .NET is a PDF component that enables users to draw different kinds of shapes in PDF document in C#, VB.NET.

Published in Shapes