CODEWITHSUNDEEP
c#
Bin
Bin

Reputation: 3

How to draw vector graphics and save it in PDF file?

I'm working on a project which generally is collecting data and drawing results in charts. (Using C#) I need to save my charts in a PDF file. My question is, how to save charts in a PDF file without loosing resolution? My point is how to draw vector graphics instead of raster graphics?

I tried iTextSharp to create PDF file but the result is not satisfying at all!

I'm new here, so I'm not able to upload pictures.

Here is the result after saving my file: https://www.dropbox.com/s/ruwtc82hfosxk6y/Test.pdf?dl=0

Here is the PDF that I need to create: https://www.dropbox.com/s/jvu5uu069imo9xc/nir%20well%20abfar.pdf?dl=0

Upvotes: 0

Views: 4389

Answers (1)

TaW
TaW

Reputation: 54433

There are two ways I know of to get high-quality images from your Chart into a PDF.

One is by using vector formats:

    1. Use chart.SaveImage with one of the three emf formats.
    1. Convert the resulting emf file to wmf
    1. Insert the wmf file into your iTextSharp document.

1 and 3 are one-liners. But step 2 is not. In fact I haven't found a working c# solution at all. The best was a weird reference to an edit that has disappeared here ..

If you can use some other program to do the conversion you will get nice results like this demo pdf file.. I used Illustrator for the conversion.

Two: If you can't get step 2 to work, you can still get nice results, if you use raster images with a nice and high resolution. Here is how to do it:

First we hide the Chart, so we don't scare the user. Then we make it as large as we want the output to be. Then we DrawToBitmap and finally we reset the chart again..:

Size s = chart1.Size;
chart1.Hide();
// pick your size in pixels
// I simply multiply my screen size..:
chart1.Size = new System.Drawing.Size(s.Width * 5, s.Height * 5);
using (Bitmap bmp = new Bitmap(chart1.ClientSize.Width, chart1.ClientSize.Height))
{
    // you should set the resolution, 
    // although I didn't find a way for iTextSharp to use it visually
    bmp.SetResolution(600, 600);
    using (Graphics G = Graphics.FromImage(bmp))
    {
        G.SmoothingMode = SmoothingMode.HighQuality;
        G.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
        chart1.DrawToBitmap(bmp, chart1.ClientRectangle);
        bmp.Save(yourImageFile, ImageFormat.Png);
    }
}
chart1.Size = s;
chart1.Show();

You could also use SaveImage and save a few lines, but you can't set the resolution of the png file there and it will be saved at the currnt screen resolution, which is 96dpi here..

Now you have a large image and will probably have to scale it down in iTextSharp:

iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(yourImageFile);
img .ScalePercent(15);  // scale to fit your needs..
doc.Add(img );

Note that the legend and the labels get very small this way, so you may have to enlarge them before saving. I also found that, when scaling down, the image is rather bright until you zoom in..

Here are two screenshots, one from the chart, the other from the pdf documnet after zooming in a lot (300%)..:

enter image description here enter image description here

Upvotes: 1

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