Hi,

At lib/PdfSharp/PdfSharp.Pdf.Internal/PdfEncoders.cs:93, pdfmod asks for the Encoding corresponding to iso-8859-1. This may fail if the user does not have mono-i18n-west installed. It would be nice to display an informational error to the user in this case instead of crashing.

example PDF to test on:

www.cwts.nl/pdf/BookofAbstracts2010_version_15072010.pdf

To reproduce:

 * Open the above PDF in pdfmod /without i18n-west installed/
 * Select some pages
 * Click 'extract' on the toolbar
 * Crash (expected: error message indicating that you don't have the right library installed)

Here's the trace

Exception in Gtk# callback delegate
  Note: Applications can use GLib.ExceptionManager.UnhandledException to handle the exception.
  System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NotSupportedException: CodePage 1252 not supported
  at System.Text.Encoding.GetEncoding (Int32 codepage) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.Internal.PdfEncoders.get_WinAnsiEncoding () [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.Internal.DocEncoding.GetByteCount (System.Char[] chars, Int32 index, Int32 count) [0x00000] in <filename unknown>:0 
  at System.Text.Encoding.GetByteCount (System.Char[] chars) [0x00000] in <filename unknown>:0 
  at System.Text.Encoding.GetByteCount (System.Char* chars, Int32 count) [0x00000] in <filename unknown>:0 
  at System.Text.Encoding.GetByteCount (System.String s) [0x00000] in <filename unknown>:0 
  at System.Text.Encoding.GetBytes (System.String s) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.IO.PdfWriter.WriteDocString (System.String text) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.PdfDate.WriteObject (PdfSharp.Pdf.IO.PdfWriter writer) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.PdfDictionary.WriteDictionaryElement (PdfSharp.Pdf.IO.PdfWriter writer, PdfSharp.Pdf.PdfName key) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.PdfDictionary.WriteObject (PdfSharp.Pdf.IO.PdfWriter writer) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.PdfDocument.DoSave (PdfSharp.Pdf.IO.PdfWriter writer) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.PdfDocument.Save (System.IO.Stream stream, Boolean closeStream) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.PdfDocument.Save (System.IO.Stream stream) [0x00000] in <filename unknown>:0 
  at PdfSharp.Pdf.PdfDocument.Save (System.String path) [0x00000] in <filename unknown>:0 
  at PdfMod.Gui.Actions.OnExtractPages (System.Object o, System.EventArgs args) [0x00000] in <filename unknown>:0 
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0 
  --- End of inner exception stack trace ---
  at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0 
  at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <filename unknown>:0 
  at System.Delegate.DynamicInvokeImpl (System.Object[] args) [0x00000] in <filename unknown>:0 
  at System.MulticastDelegate.DynamicInvokeImpl (System.Object[] args) [0x00000] in <filename unknown>:0 
  at System.Delegate.DynamicInvoke (System.Object[] args) [0x00000] in <filename unknown>:0 
  at GLib.Signal.ClosureInvokedCB (System.Object o, GLib.ClosureInvokedArgs args) [0x00000] in <filename unknown>:0 
  at GLib.SignalClosure.Invoke (GLib.ClosureInvokedArgs args) [0x00000] in <filename unknown>:0 
  at GLib.SignalClosure.MarshalCallback (IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data) [0x00000] in <filename unknown>:0 
  at GLib.ExceptionManager.RaiseUnhandledException(System.Exception e, Boolean is_terminal)
  at GLib.SignalClosure.MarshalCallback(IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data)
  at Gtk.Application.gtk_main()
  at Gtk.Application.Run()
  at PdfMod.Gui.Client..ctor(Boolean loadFiles)
  at PdfMod.PdfMod.Main(System.String[] args)
Cairo.Context: called from finalization thread, programmer is missing a call to Dispose

Forwarded from http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=618365