[Marble] Encoding artefacts in exported map

[v_2e at ukr.net]

  Hello!
  I have the following problem. I'm trying to save the map I'm
currently viewing to a file. I'm using "File" -> "Export Map..." for
this. But the resulting file is of a low quality. There is a
substantial amount of noise near the contrast edges in it.
  Is there a way to export a map into a high-quality PNG file with no
encoding artefacts?

  Thank you.
    Vladimir

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 <v_2e at ukr.net>