Aspose.Imaging.CoreExceptions.FrameworkException: Cannot allocate so many bytes. Use LoadPartialPixels instead. Cannot allocate so many bytes. Use LoadPartialPixels instead. - Grayscale Conversion

Aspose.PDF Product Family
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1

Hi,

We are getting “Aspose.Imaging.CoreExceptions.FrameworkException: Cannot allocate so many bytes. Use LoadPartialPixels instead.” & “System Out of Memory” during the grayscale conversion. We are using the latest Aspose version of 24.9.0 and attached is the code we used for grayscale conversion.

using (Aspose.Pdf.Document document = new Aspose.Pdf.Document(item.FullName))
{
Aspose.Pdf.RgbToDeviceGrayConversionStrategy strategy = new Aspose.Pdf.RgbToDeviceGrayConversionStrategy();
for (int idxPage = 1; idxPage <= document.Pages.Count; idxPage++)
{
Page page = document.Pages[idxPage];
try
{
strategy.Convert(page);
}
catch (Exception ex)
{
WriteErrorLog("ConverttoGrayscalePDF Exception - " + " - " + ex);
continue;
}
}
document.Save(ConvertedImagePath);
document.Dispose();
}

2

@Aswin0892

The error message “Aspose.Imaging.CoreExceptions.FrameworkException: Cannot allocate so many bytes. Use LoadPartialPixels instead.” along with “System Out of Memory” typically indicates that the operation you are trying to perform is consuming more memory than is available. This can happen during the grayscale conversion process, especially with large PDF files or images.

To address this issue, you can consider the following approaches:

  1. Use LoadPartialPixels: The error message suggests using LoadPartialPixels instead of loading the entire image into memory. This method allows you to load only a portion of the image, which can significantly reduce memory usage.

  2. Process Pages Individually: If you are processing a large PDF, consider converting each page to grayscale one at a time and saving the intermediate results. This can help manage memory usage more effectively.

  3. Optimize PDF Size: If possible, try to reduce the size of the PDF before performing the conversion. This can be done by compressing images or removing unnecessary elements from the PDF.

Here is a sample code snippet that demonstrates how to convert a PDF to grayscale while processing each page individually:

using (Aspose.Pdf.Document document = new Aspose.Pdf.Document("input.pdf"))
{
    Aspose.Pdf.RgbToDeviceGrayConversionStrategy strategy = new Aspose.Pdf.RgbToDeviceGrayConversionStrategy();
    for (int idxPage = 1; idxPage <= document.Pages.Count; idxPage++)
    {
        Page page = document.Pages[idxPage];
        try
        {
            strategy.Convert(page);
        }
        catch (Exception ex)
        {
            Console.WriteLine("ConverttoGrayscale Exception - " + ex.Message);
            continue;
        }
    }
    document.Save("output.pdf");
}

Make sure to monitor the memory usage during the conversion process and adjust your approach as necessary. If the problem persists, consider reaching out to Aspose support for further assistance.

If you need more detailed examples or specific guidance, you can refer to the official documentation or community posts related to grayscale conversion in Aspose.PDF.

Sources:
[1]: ConvertFromRGBToGrayscale.cs
[2]: ConvertPDFFromRGBColorspaceToGrayscale.java