Out of Memory exception when saving Excel as grayscale TIFF

Aspose.Cells Product Family
1

I’m trying to convert an Excel spreadsheet to a grayscale TIFF using the following code:

      var fileStream = File.OpenRead("SomeTestFile.xlsx");
      var excel = new Workbook(fileStream);

      var options = new ImageSaveOptions(SaveFormat.TIFF);

      options.ImageOrPrintOptions.HorizontalResolution = 200;
      options.ImageOrPrintOptions.VerticalResolution = 200;
      options.ImageOrPrintOptions.TiffCompression = TiffCompression.CompressionLZW;
      options.ImageOrPrintOptions.PixelFormat = PixelFormat.Format16bppGrayScale;

      var memoryStream = new MemoryStream();

      excel.Save(memoryStream, options);

When I run this I get an Aspose.Cells.CellsException : Out of memory. The test Excel file is only 50kb and I have plenty of memory. If I run the same code using PixelFormat.Format16bppRgb555 or PixelFormat.Format24bppRgb it works fine. I am also able to use TiffCompression.CompressionCCITT3 to get a bitonal image, but I would like a grayscale image. For now I’m just converting the TIFF to grayscale after saving, but it adds a little extra time to the process.


I’m using the .NET 3.5 ClientProfile v8.7.1.0 (due to the issues with CAS and GDI+ as noted here: Aspose Cells security critical exception) Thanks for any help.

2

Hi Walter,


Thank you for contacting Aspose support.

We have evaluated the presented scenario while using the latest version of Aspose.Cells for .NET 8.7.1.1 and following piece of code against a sample of my own. We are able to replicate the CellsException: Out of memory while saving the Workbook to TIFF in grayscale therefore we have logged this incident as CELLSNET-44275 for further investigation. Please spare us little time to properly analyze the problem cause and get back with updates in this regard.
3

Great, thanks very much. If it makes any difference, we are current customers for several Aspose products. If it would be helpful I can retrieve our licensing information.

4

Hi Walter,


We do not require your licensing information to provide the fix for the mentioned issue. We will share investigation results here as soon as we have completed the preliminary analysis.
5

Hi,


We have evaluated your issue further.
Please refer to the page:
https://bytes.com/topic/c-sharp/answers/278572-out-memory-graphics-fromimage it seems that PixelFormat16bppGrayScale is not supported by GDI+. So, you can set BlackAndWhite to true in PageSetup of worksheet before rendering to get a gray scale image:
e.g
Sample code:

var book = new Workbook(srcFile);
WorksheetCollection sheets = book.Worksheets;
foreach (Worksheet sheet in sheets)
{
sheet.PageSetup.BlackAndWhite = true;
}
…

Hope, this helps a bit.

Thank you.
6

Thanks for the information, that helps. I’ll continue using my grayscale converter after exporting, since it drops the file size quite a bit.