Re: [Tuxpaint-devel] Is this warning harmless?

[Bill K. <nb...@so...>]

On Tue, Nov 02, 2021 at 09:44:39PM +0900, TOYAMA Shin-ichi wrote:
> Hi,
> 
> I think the reason for this warning is that the size of wchar_t is
> 4 bytes on linux but 2 bytes on windows.
> 
> I don't know what render_text_w() is doing, so I'm not sure if
> this is the problem or not.
> 
> For example, the text circled in red in onscreen_keyboard (see 
> attached) does not seem to be rendered on windows.
> 
> Does this seem relevant ?

Hrm, we have some clues about this in the code from John P. from
way back in 2006:

  https://sourceforge.net/p/tuxpaint/tuxpaint/ci/304f49672/

Specifically, this part of the commit message:

  Modified the text gadget so that it correctly handles the 16-bit unicode
  characters that SDL sends. The text buffer is held internally as an array
  of wchar_t, and makes uses of various wide-character functions.
  It is converted back into 16-bit unicode characters to satisfy SDL_ttf.
  Tested on Windows and Linux.

And it's this function:

  // This conversion is required on platforms where Uint16 doesn't match wchar_t.
  // On Windows, wchar_t is 16-bit, elsewhere it is 32-bit.
  // Mismatch caused by the use of Uint16 for unicode characters by SDL, SDL_ttf.
  // I guess wchar_t is really only suitable for internal use ...
  static Uint16 *wcstou16(const wchar_t *str)
  ...

It is used in exactly one place, within render_text_w():

  if (font->typ == FONT_TYPE_TTF)
    {
      ustr = wcstou16(str);
      ret = TTF_RenderUNICODE_Blended(font->ttf_font, ustr, color);
      free(ustr);
    }


However, we're talking about the bit of code that constructs
UTF-8 Unicode within Tux Paint, to deliver it to SDL_Pango.

I think it might be worth replacing `wchar` with something
like Uint32 for these purposes...

I'm digging around the code right now.

-bill!


> 
> 
> TOYAMA Shin-ichi wrote in <617e94b2.5007%sh...@wm...>
> >Hi,
> >
> >Recently, I've been dealing with a lot of bugs in the Windows
> >version, and I've noticed that many clue of the bugs had been 
> >appeared in the compile-time warnings.
> >
> >So,I checked the warnings again, and the following warning,
> >which does not appear when compiling on Linux, caught my 
> >attention.
> >
> >------------------------------------------------------------
> >src/tuxpaint.c: In function 'render_text_w':
> >src/tuxpaint.c:1685:27: warning: comparison is always true due to limited range 
> >of data type [-Wtype-limits]
> > 1685 |           else if (str[i] <= 0x0000FFFF)
> >------------------------------------------------------------
> >
> >If this warning is correct, it means that the next conditional
> >branch (0x00100000 - 001FFFFF) will never be reached.
> >
> >How can I confirm if it were a problem or not?
> >
> >Thanks!
> 
> -- 
> TOYAMA Shin-ichi mailto:sh...@wm...



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-- 
-bill!
Sent from my computer