Save() Method Increasing Image Size

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#1 Posted : Thursday, May 10, 2018 2:08:01 PM(UTC)

Toadfish

Groups: Registered
Posts: 20

Hey all,

When I try converting a page from PDF to SVG, the resulting total SVG pages is bigger than the originial PDF. The original PDF is 2MB and when all the pages are converted to SVG, each is about 0.2-0.3MB. Resulting in a total of about 45MB getting sent from the API.

Here is some example code of converting the first page of the document into a byte[]. The resulting pageByteArray is usually larger than the original document.

Code:


...
MemoryStream stream = new MemoryStream(documentData); //documentData is base64, 280 page, 2MB PDF
var document = DocumentFactory.LoadFromStream(stream, new LoadDocumentOptions());
var documentPage = document.Pages[0];

if (documentPage.IsSvgSupported)
{
    var pageByteArray = CreateSVGPage(documentPage);
}
...
public static byte[] CreateSVGPage(DocumentPage documentPage)
{
    using (var svgDocument = documentPage.GetSvg(new CodecsLoadSvgOptions()))
    {
        if (svgDocument != null)
        {
            if (!svgDocument.IsFlat)
                svgDocument.Flat(null);

            if (!svgDocument.IsRenderOptimized)
                svgDocument.BeginRenderOptimize();

            var svgBounds = svgDocument.Bounds;
            if (!svgBounds.IsValid)
                svgDocument.CalculateBounds(false);
        }

        if (svgDocument != null)
        {
            var gzip = false;
            var gzipString = ServiceHelper.GetSettingValue(ServiceHelper.Key_Svg_GZip);
            if (!string.IsNullOrEmpty(gzipString))
            {
                if (!bool.TryParse(gzipString, out gzip))
                    gzip = false;
            }

            var stream = ToStream(svgDocument, gzip);

            var currentContext = HttpContext.Current;
            if (currentContext != null)
            {
                if (gzip)
                    currentContext.Response.Headers.Add("Content-Encoding", "gzip");

                currentContext.Response.ContentType = "image/svg+xml";
                currentContext.Response.Headers.Add("ContentLength", stream.Length.ToString());
            }

            MemoryStream ms = new MemoryStream();
            stream.CopyTo(ms);
            return ms.ToArray();
        }
        else
        {
            return null;
        }
    }
}
...

private static Stream ToStream(SvgDocument svgDocument, bool gzip)
{
var ms = new MemoryStream();

var svgSaveOptions = new SvgSaveOptions();

if (gzip)
{
using (var compressed = new GZipStream(ms, CompressionMode.Compress, true))
{
using (var tempStream = new MemoryStream())
{
svgDocument.SaveToStream(tempStream, svgSaveOptions);
tempStream.Position = 0;
ServiceHelper.CopyStream(tempStream, compressed);
}
}
}
else
{
svgDocument.SaveToStream(ms, svgSaveOptions);
}

ms.Position = 0;
return ms;
}


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#2 Posted : Tuesday, May 15, 2018 7:05:38 AM(UTC)

Christopher Thompson

Groups: Registered, Tech Support, Administrators
Posts: 89

Was thanked: 4 time(s) in 4 post(s)

Hi,

The size of each of the pages converted from your PDF to SVG is dependent on the type of data that is on each of the pages in the PDF.
I ran a quick test in our LEADTOOLS convert demo and the resulting conversion showed that the pages that held graphical images were much larger in size when compared with those pages with just text.

Have you tried to use the LEADTOOLS convert demo to test the results there?
This would allow you to compare the results in your application with that of the demo.

This demo can be found in the following default file path from the v19 SDK download:
C:\LEADTOOLS 19\Shortcuts\Document Converter\.NET Class Libraries
or v20
C:\LEADTOOLS 20\Shortcuts\Document Converter\.NET Framework Class Libraries

Also, you could look into the ConvertToSvg Method that is part of the Leadtools.Pdf namespace in our LEADTOOLS Online Documentation.

Chris Thompson
Developer Support Engineer
LEAD Technologies, Inc.

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