PDF generated with iTextSharp adding image gets poor quality

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PDF generated with iTextSharp adding image gets poor quality

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I have an image file that I need to pass to PDF and for this I am using iTextSharp .

I'm trying to do this in the following way:

private static void Main(string[] args)
{
    using (var stream = new FileStream("document.pdf", FileMode.Create))
    {
        using (var document = new Document(PageSize.A4))
        {
            PdfWriter.GetInstance(document, stream);

            document.SetMargins(20, 20, 20, 20);
            document.AddCreationDate();
            document.Open();

            using (var picture = new Bitmap("model256.bmp"))
            {
                double percentage;
                if (picture.Height > picture.Width)
                    percentage = document.PageSize.Height / picture.Height;
                else
                    percentage = document.PageSize.Width / picture.Width;

                using (var newPicture = Util.ResizeImage(picture, 
                    Convert.ToInt32(picture.Width * percentage), 
                    Convert.ToInt32(picture.Height * percentage)))
                {
                    var image = iTextSharp.text.Image.GetInstance(newPicture, 
                        BaseColor.WHITE);
                    image.Alignment = Element.ALIGN_CENTER;

                    document.Add(image);
                    document.Close();
                }
            }
        }
    }
}

With this help to resize:

public static class Util
{
    public static Bitmap ResizeImage(Bitmap bitmap, int newWidth, int newHeight)
    {
        var width = bitmap.Width;
        var heigth = bitmap.Height;

        if (width > newWidth || heigth > newHeight)
        {
            if (width > heigth)
            {
                heigth = (heigth * newWidth) / width;
                width = 500;
            }
            else
            {
                width = (width * newHeight) / heigth;
                heigth = 500;
            }
        }

        var image = bitmap.GetThumbnailImage(width, heigth, null, new System.IntPtr(0));
        return new Bitmap(image);
    }
}

The format of the images is bmp .

Here you have the images placed side by side for comparison

The stackoverflow editor resizes the images so it looks bad here. But by clicking on both images it appears in real size and with the right quality.

HowtogeneratePDFwithgoodimagequality?

EDITION

MakinguseofGraphics

UsingGraphicstotrytoimprovetheoutputimagealsohasnotbeenimproved.

private static void Main(string[] args)
{
    using (var stream = new FileStream("document.pdf", FileMode.Create))
    {
        using (var document = new Document(PageSize.A4))
        {
            PdfWriter.GetInstance(document, stream);

            document.SetMargins(20, 20, 20, 20);
            document.AddCreationDate();
            document.Open();

            using (var picture = new Bitmap("original.bmp"))
            {
                var width = Convert.ToInt32(Math.Round(
                    document.PageSize.Width - 40));
                var height = Convert.ToInt32(Math.Round(
                    ((float)picture.Height / (float)picture.Width) * (width)));

                using (var newPicture = Util.RedimensionarImagem(
                    picture, width, height, PixelFormat.Format48bppRgb))
                {
                    var image = Image.GetInstance(newPicture, BaseColor.WHITE);
                    image.Alignment = Element.ALIGN_CENTER;

                    document.Add(image);
                    document.Close();
                }
            }
        }
    }
}

And the resize routine:

public static Image RedimensionarImagem(Image image, int width, int height, PixelFormat pf)
{
    if (image != null)
    {
        var newImage = new Bitmap(width, height, pf);
        using (var gr = Graphics.FromImage(newImage))
        {
            //gr.SmoothingMode = SmoothingMode.HighQuality;
            gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
            //gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
            gr.DrawImage(image, 0, 0, width, height);
            gr.Dispose();
            return newImage;
        }
    }
    return null;
}

Sample image:

ResizingbyobjectiTextSharp.text.Image

Whenusingtheoriginalimagewithoutresizingit,andresizingtheiTextSharpobject,Iwasabletogetalittleimprovement.

Inseveralattemptstoresizetheimageforthebestconversion,InoticedthattherewasstillalosswhenpassingtheimagetoiTextSharpImageandthentoDocument

Butstillitpresentsanimagewithlowquality!

Code:

using (var document = new Document(PageSize.A4))
{
    document.SetMargins(20, 20, 20, 20);
    document.AddCreationDate();
    document.Open();

    using (var picture = new Bitmap("original.bmp"))
    {
        var width = Convert.ToInt32(Math.Round(document.PageSize.Width - 40));
        var height = Convert.ToInt32(Math.Round(((float)picture.Height / (float)picture.Width) * (width)));

        using (var writer = PdfWriter.GetInstance(document, stream))
        {
            writer.SetPdfVersion(PdfWriter.PDF_VERSION_1_7);
            writer.CompressionLevel = PdfStream.NO_COMPRESSION;

            document.Open();

            var image = iTextSharp.text.Image.GetInstance(bitmap, BaseColor.WHITE);
            image.Alignment = Element.ALIGN_CENTER;

            image.SetDpi(600, 600);
            image.ScaleToFit(width, heigth);

            document.Add(image);
            document.Close();
        }
    }
}

Result

c# imagem itextsharp

asked by anonymous 22.11.2017 / 00:47

1 answer

Variable to call where to search the database! Preventing sending data when updating page F5 in ASP.NET

score 0 · Answer 1

In your image resize method, you are using

var image = bitmap.GetThumbnailImage(width, heigth, null, new System.IntPtr(0));
return new Bitmap(image);

This method returns a thumbnail of the last image. You should not use this.

Here is a function that I use to resize the image:

public static System.Drawing.Image RedimensionarImagem(System.Drawing.Image srcImage, int newWidth, int newHeight, PixelFormat pf)
{
    if (srcImage != null)
    {
        Bitmap newImage = new Bitmap(newWidth, newHeight, pf);
        using (Graphics gr = Graphics.FromImage((Image)newImage))
        {
            //gr.SmoothingMode = SmoothingMode.HighQuality;
            gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
            //gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
            gr.DrawImage(srcImage, 0, 0, newWidth, newHeight);// new Rectangle(0, 0, newWidth, newHeight));
            gr.Dispose();
            return (Image)newImage;
        }
    }
    else
        return null;

}

To run the call:

var image = RedimensionarImagem(bitmap, width, height, PixelFormat.Format24bppRgb);

GetThumbnailImage Method documentation: link