Hi. I am reposting this message that I have yet to receive a reply on, which I originally posted 4 days ago under a different but related thread. This issue is very important to my evaluation of Aspose.Slides, so any reply would be helpful…even just a message that it’s being looked into.
I’m evaluating Aspose.Slides for .Net and using version 2.8.4.0.
We
use EMF images of charts in our presentations. We have found that
using a vector format such as this is absolutely essential to having
high quality images for printing while retaining reasonable file sizes.
The
PowerPoints we create using Aspose show the EMF format fine and look
great. However, when we call Presentation.SaveToPdf(System.IO.Stream),
it appears that the EMF format images are being converted into very low
quality images before they are added to the PDF. This is not a
limitation of PDF, because if we manually use Acrobat to convert the
same PowerPoint to PDF, the images are embedded as EMF format.
What
is important to us is using some sort of vector format image, not EMF
specifically, so I tried SVG. This led to the exception:
System.ArgumentExceptionGetting
Parameter is not valid.
at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateImageData)
at System.Drawing.Image.FromStream(Stream stream)
at Aspose.Slides.PPImage…ctor(Presentation parent, Stream stream, Boolean close_stream)
at Aspose.Slides.Picture…ctor(Presentation parent, Stream stream)
at
WorkplaceDynamics.Results.Presenting.Summaries.insertFactorStatementsHeatMap(User
user, Int32 surveyEventId, Factor factor, Shape shape) in
C:\VersionControl\Applications\Results\Trunk\WorkplaceDynamics.Results.Presenting\Summaries.cs:line
150
at
WorkplaceDynamics.Results.Presenting.Summaries.customizeSlide(User
user, Int32 surveyEventId, Slide slide, Factor topFactor, Factor
bottomFactor) in
C:\VersionControl\Applications\Results\Trunk\WorkplaceDynamics.Results.Presenting\Summaries.cs:line
62
at
WorkplaceDynamics.Results.Presenting.Summaries.customizePresentation(User
user, Int32 surveyEventId, Presentation presentation) in
C:\VersionControl\Applications\Results\Trunk\WorkplaceDynamics.Results.Presenting\Summaries.cs:line
44
at
WorkplaceDynamics.Results.Presenting.Summaries.WriteSummaryToStream(Stream
stream, User user, Int32 surveyEventId, String templateDirectory,
Boolean isPdf) in
C:\VersionControl\Applications\Results\Trunk\WorkplaceDynamics.Results.Presenting\Summaries.cs:line
23
at
WorkplaceDynamics.Results.UI.Summary.ProcessRequest(HttpContext
context) in
C:\VersionControl\Applications\Results\Trunk\WorkplaceDynamics.Results.UI\Summary.ashx.cs:line
32
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
the exception isn’t surprising, as Microsoft products typically have
better support for EMF than for SVG, but the stack trace suggests one
possible explanation for the EMF issue. System.Drawing.Image does not
natively support saving EMF files.
The Microsoft documentation (Image.Save Method (System.Drawing) | Microsoft Learn) indicates:
If no encoder exists for the file format of the image, the Portable Network Graphics (PNG) encoder is used. When you use the SaveThis sounds a lot like what is happening when the PowerPoint is saved to PDF using SaveToPdf()
method to save a graphic image as a Windows Metafile Format (WMF) or
Enhanced Metafile Format (EMF) file, the resulting file is saved as a
Portable Network Graphics (PNG) file. This behavior occurs because the
GDI+ component of the .NET Framework does not have an encoder that you
can use to save files as .wmf or .emf files.
So
with all that said, is there any way that I can use Aspose to save a
dynamically created PowerPoint that contains EMF images to a PDF that
retains the high quality of the EMF images?
Not being able to do this makes the output so unprofessional looking that we will not be able to use the product.
We
would be willing to buy both Aspose.Slides and Aspose.PDF if that’s
what it took, but I don’t see any mention of the PowerPoint format in
the Aspose.PDF marketing pages on the web site.
Thank you very much for your help!
Rick