Re: Cygwin fails to utilize Unicode replacement character

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

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On Sep  3 14:46, Corinna Vinschen wrote:
> On Sep  2 05:51, Steven Penny wrote:
> > On Sun, 2 Sep 2018 10:07:10, Thomas Wolff wrote:
> > > Actually, the width problem I suggested in my other response (and even
> > > referring to the wrong character) does not apply as mintty enforces
> > > proper width in that case.
> > > Also, even with fonts that do not provide the glyph, you will usually
> > > still see it by the Windows font fallback mechanism.
> > > Shall I make it configurable?
> > 
> > your call - here are the possible resolutions - in order of my preference:
> > 
> > 1. Change the default to U+FFFD with no option
> > 2. Change the default to U+FFFD with option to change
> > 3. Leave default as is with option to change
> 
> Ideally we could check if the current font supports a visual
> representation of 0xfffd and if not, fall back to 0x2592.
> 
> Not sure how feasible that is, but it doesn't seem to be overly
> complicated.  I'm just looking into a solution for the Cygwin
> console.

Only, I can't get this working.  In theory the GDI function
GetGlyphIndicesW is supposed to allow checking if a certain character
exists.  But I'm getting a weird result.  This code:

  static const wchar_t replacement_char[2] =
    {
      0xfffd, /* REPLACEMENT CHARACTER */
      0x2592  /* MEDIUM SHADE */
    };
  HWND cwnd = GetConsoleWindow ();
  HDC cdc = GetDC (cwnd);
  int rp_idx = 0;
  WORD gi = 0;
  DWORD ret = GetGlyphIndicesW (cdc, replacement_char, 1, &gi,
                                GGI_MARK_NONEXISTING_GLYPHS);
  if (ret != GDI_ERROR && gi == 0xffff)
    rp_idx = 1;

always sets rp_idx to 1 when called from inside the Cygwin DLL,
independently of the actual console font.  And, here's the really weird
thing, it always sets rp_idx to 0 when called directly from an
application, likewise independently of the actual console font.

Does anybody have an idea what I'm doing wrong?

Just as side-note:

- GetTextFaceW always returns font number 7 called "System", independently
  of the actual current font set in the console.
- GetCurrentConsoleFont always returns a font number of 0, independently
  of the actual current font set in the console.
  GetCurrentConsoleFontEx always returns with error 87, "invalid
  parameter"

Something's very fishy.  Thanks for any actual help.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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