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Aspose Slides Thumbnail Generation

When using asian character sets all the characters on the thumbnail become squares. Does aspose support generating thumbnail images of slides written using unicode characters? If so what extra steps are necessary so that the thumbnails render appropriately?

This message was posted using Page2Forum from Creating Slide Thumbnail Image - Aspose.Slides for .NET and Java

Dear hoopscoach,

Thanks for considering Aspose.Slides.

There are no extra steps; it generates the image with Unicode characters. Please provide your source presentation, so that we could investigate and fix this bug.

This is the code I’m using to convert the powerpoint files to thumbnails. I’ve attached an example slide and the resulting thumbnail.

using System;
using System.Collections.Generic;
using System.Text;
using Aspose.Slides;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace LargeThumbnailCreator
class Program
static void Main(string[] args)
License lic = new License();
string baseDir = Properties.Settings.Default.BasePath;
string slidesDir = Properties.Settings.Default.SourcePPTFolder;
string outDir = Properties.Settings.Default.OutJPGFolder;
System.IO.DirectoryInfo dir = new DirectoryInfo(Path.Combine(baseDir, slidesDir));

FileInfo[] files = dir.GetFiles("*.pot");
int count = 1;

foreach (FileInfo file in files)
string mess = string.Format("File {0} of {1}", count, files.Length);

//get full size image at 75% jpg quality
Image fullimage = GetSlideImage(file.FullName, 0, 1, .9398, "");

if (fullimage == null)

foreach (string percent in Properties.Settings.Default.Percents)

double ratio = Convert.ToDouble(percent) / 100;

Image thumb = fullimage.GetThumbnailImage((int)(fullimage.Width * ratio), (int)(fullimage.Height * ratio), null, IntPtr.Zero);

string mess2 = string.Format("{0}% generated", ratio);

string fullFilename = Path.Combine(baseDir, Path.Combine(outDir, string.Format(@"{0}\{1}.jpg", percent, Path.GetFileNameWithoutExtension(file.Name))));
EncoderParameters encoderParameters = new EncoderParameters(1);
encoderParameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, Properties.Settings.Default.JPGQuality);
ImageCodecInfo imageCodecInfo = GetEncoderInfo("image/jpeg");
thumb.Save(fullFilename, imageCodecInfo, encoderParameters);
catch (Exception ex)
string mess3 = string.Format("Error encountered, skipping");



private static ImageCodecInfo GetEncoderInfo(String mimeType)
int j;
ImageCodecInfo[] encoders;
encoders = ImageCodecInfo.GetImageEncoders();
for (j = 0; j < encoders.Length; ++j)
if (encoders[j].MimeType == mimeType)
return encoders[j];
return null;

public static Image GetSlideImage(string presentationFilePath, int slideIndex, double width, double height, string licensePath)
Aspose.Slides.Presentation tempPresentation = GetPresentationObject(presentationFilePath);
if (tempPresentation == null)
return null;
return tempPresentation.Slides[slideIndex].GetThumbnail(width, height);

public static Aspose.Slides.Presentation GetPresentationObject(string presentationFilePath)
FileStream presStream = new FileStream(presentationFilePath, FileMode.Open, FileAccess.Read);
Aspose.Slides.Presentation tempPresentation = new Aspose.Slides.Presentation(presStream);
return tempPresentation;
catch (Exception)
return null;

Just wondering if any progress had been made on this. Thanks!

Still hoping for a response on this.

Thank you for patience. Please wait for couple of weeks.

Sounds good, thanks for your response!

Are you sure you have SimSun font installed on the computer where you generate thumbnail?
I have it and thumbnail is correct.

That was the problem I didn’t realize the font wasn’t there. Thank you!