screen-glyph-exists? in font%
Returns #t if the given character has a corresponding glyph
when drawing to the screen or a bitmap, #f otherwise.
If the second argument is true, the result indicates whether the glyph
is available for control labels. Otherwise, it indicates whether the
glyph is available for dc<%> drawing.
For dc<%> drawing, due to automatic font substitution when
drawing or measuring text, the result of this method does not depend
on this font's attributes (size, face, etc.). The font's attributes
merely provide a hint for the glyph search.
See also
glyph-exists? .