Cygwin fails to utilize Unicode replacement character

[Corinna Vinschen]

On Sep  3 18:34, Thomas Wolff wrote:
> Am 03.09.2018 um 16:59 schrieb Corinna Vinschen:
> > 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?
> This works in mintty, just uploaded a patch. Maybe somehow the GetConsole
> "dc" does not support this usage?

¯\_(ツ)_/¯

But I'm glad it works for you.


Corinna

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