Patch by Sergei Golovan.

It ensures that font size is positive (measured in pixels). This fixes
mirrored text problem in canvas postscript output.

--- tk8.5-8.5.5.orig/unix/tkUnixRFont.c
+++ tk8.5-8.5.5/unix/tkUnixRFont.c
@@ -260,6 +260,7 @@
     ftFont = GetFont(fontPtr, 0);
     fontPtr->font.fid = XLoadFont(Tk_Display(tkwin), "fixed");
     GetTkFontAttributes(ftFont, &fontPtr->font.fa);
+    fontPtr->font.fa.size = TkFontGetPoints(tkwin, fontPtr->font.fa.size);
     GetTkFontMetrics(ftFont, &fontPtr->font.fm);
 
     return fontPtr;
@@ -518,6 +519,7 @@
 
     GetTkFontAttributes(ftFont, faPtr);
     faPtr->underline = fontPtr->font.fa.underline;
+    faPtr->size = TkFontGetPoints(tkwin, faPtr->size);
     faPtr->overstrike = fontPtr->font.fa.overstrike;
 }