The wxPdfDC::DrawPoint calls wxPdfDocument::Rect to draw a rectangle of 1 pixel width and height, but supplies it with a pair of x/y from-and-to coordinates, instead of x/y/width/height.
Fix below as a unified diff:
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Index: pdfdc29.inc
===================================================================
--- pdfdc29.inc (revision 3182)
+++ pdfdc29.inc (working copy)
@@ -577,7 +577,7 @@
double xx = ScaleLogicalToPdfX(x);
double yy = ScaleLogicalToPdfY(y);
m_pdfDocument->SetFillColour(m_pdfDocument->GetDrawColour());
Fixed in wxCode SVN