Frequently Asked Question:

Return to FAQ Index

If I have an existing PDF that has a graphic on it, and I simply want a user to be able to click a point on the PDF and drop a letter at the point of the click, like A... B... etc. Is this possible using Quick PDF Library?

Yes, this is possible using Quick PDF Library. Here is an example of how to do this using C#:

using System;
using System.IO;
using System.Drawing;
using System.Windows.Forms;
using QuickPDFAX0718;

namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
private string LicenseKey = " your key here ";
private string OriginalFileName = "D:\\QuickPDFLibrary\\hello1.pdf";
private string NewFileName = "D:\\QuickPDFLibrary\\hello2.pdf";

public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
ShowPDF(OriginalFileName);
}

private void ShowPDF(string fileName)
{
PDFLibrary qp = new PDFLibrary();
qp.UnlockKey(LicenseKey);
qp.LoadFromFile(fileName);

// Fit width of PDF to width of picture box
int dpi = Convert.ToInt32((pictureBox1.Width * 72) / qp.PageWidth());
byte[] bmpData = (byte[])qp.RenderPageToVariant(dpi, 1, 0);

MemoryStream ms = new MemoryStream(bmpData);
Bitmap bmp = new Bitmap(ms);
pictureBox1.Image = bmp;

ms.Dispose();
}

private void pictureBox1_MouseClick(object sender, MouseEventArgs e)
{
PDFLibrary qp = new PDFLibrary();
qp.UnlockKey(LicenseKey);
qp.LoadFromFile(OriginalFileName);

// Calculate co-ordinates, width of PDF fitted to width of PictureBox
double xpos = ((double)e.X / (double)pictureBox1.Width) * qp.PageWidth();
double ypos = qp.PageHeight() - ((double)e.Y / (double)pictureBox1.Width) * 
qp.PageWidth();

qp.SetTextSize(24);
qp.SetTextColor(1, 0, 0);
qp.DrawText(xpos, ypos, "A");

qp.SaveToFile(NewFileName);
ShowPDF(NewFileName);
}

}
}