P4
There are cases the fallback font returned by DirectWrite is not available to JFX.
For example, on Windows8 using "Meiryo Bold Italic" to render korean text, because the font does not have korean DW will tell us to use "Segoe UI Bold Oblique", the JFX does not have that font, so it returns Segoe UI Bold Italic. Turns out these are not the same font, so we end up with glyph index from a font and rendering with another. The result is garbage.
For example, on Windows8 using "Meiryo Bold Italic" to render korean text, because the font does not have korean DW will tell us to use "Segoe UI Bold Oblique", the JFX does not have that font, so it returns Segoe UI Bold Italic. Turns out these are not the same font, so we end up with glyph index from a font and rendering with another. The result is garbage.