使用iTextSharp将已停用图层的PDF转换为PNG

Question

我正在使用iTextSharp。我正在处理一个PDF，它有我称之为很多的＆＃34;层＆＃34;。

因此，当我打开PDF时，我可以制作我的＆＃34;层＆＃34;通过单击图层名称左侧的小眼睛可见或不可见。

我知道如何激活/停用图层，使用以下代码：

FileStream outStream = null;
        PdfReader pdfReader = null;
        PdfStamper stamper = null;

        Exception exceptionOccured = null;
        try
        {
            outStream = new FileStream(destFile, FileMode.Create);
            pdfReader = new PdfReader(sourceFile);
            stamper = new PdfStamper(pdfReader, outStream);

            Dictionary<String, PdfLayer> layers = null;
            try
            {
                layers = stamper.GetPdfLayers();
            }
            catch (Exception)
            {
            }
            if (layers != null)
            {
                layersToRemove = addSpecialLayerChars(layersToRemove);

                foreach (KeyValuePair<String, PdfLayer> layer in layers)
                {
                    //Encodage UTF-16 BE 'þÿ' retirer les \0
                    String layerName = layer.Key;
                    String layerNameComp = layerName.Replace("\0", "");
                    layerNameComp = layerNameComp.Replace("þÿ", "");

                    Boolean remove = false;
                    //Si(!layerName.equals("textes")) Alors remove = true; // On efface toute les couches qui ne contiennent pas de texte
                    foreach (String layerToRemove in layersToRemove)
                    {
                        if (layerNameComp.ToLowerInvariant() == layerToRemove.ToLowerInvariant())
                        {
                            remove = true;
                        }
                        else if (layerToRemove[layerToRemove.Length - 1] == '*')
                        {
                            if (layerNameComp.ToLowerInvariant().StartsWith(layerToRemove.Substring(0, layerToRemove.Length - 1).ToLowerInvariant()))
                            {
                                remove = true;
                            }
                        }
                    }
                    if (remove)
                    {
                        if (writeToConsole)
                            Console.WriteLine("Removing layer: " + layerName);
                        try
                        {
                            layers[layerName].On = false;
                        }
                        catch (Exception ex)
                        {
                            if (writeToConsole)
                                Console.WriteLine("Exception: " + ex.Message);
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            exceptionOccured = ex;
        }
        finally
        {
            try
            {
                if (stamper != null)
                    stamper.Close();
                if (pdfReader != null)
                    pdfReader.Close();
                if (outStream != null)
                    outStream.Close();
                if (exceptionOccured != null)
                    throw exceptionOccured;
            }
            catch (Exception ex)
            {
                if (exceptionOccured != null)
                    throw exceptionOccured;
            }
        }

但是当我想将我的PDF（带有停用的图层）转换为PNG时，我的新图像包含所有图层，甚至包括我停用的图层。

这就是我想完全删除图层的原因。