Re: [screen-devel] [PATCH] :hardcopy: handle encoding (Was: Hardcopy uses ISO-8859-1)

[Alex Naumov]

Hi Simon,

first of all, thank you very much for this patch.
It takes a bit time: I just want to compare this code with our unicode++ branch.

Cheers,
Alex

On Sat, Feb 6, 2016 at 4:39 PM, Simon Ruderich <address@hidden> wrote:
> On Tue, Jan 26, 2016 at 02:46:29PM +0100, Simon Ruderich wrote:
>> Hi,
>>
>> I'm using GNU screen's hardcopy function to dump the current
>> screen content to a file. However the resulting file is encoded
>> in ISO-8859-1 although my current locale is UTF-8. This causes
>> corruption for characters which are not representable in
>> ISO-8859-1.
>
> Hello again,
>
> It's not actually using ISO-8859-1, but instead printing the
> first byte of ->image which seems to be the unicode code point.
>
> image.h:
>     /* structure representing single cell of terminal */
>     struct mchar {
>             uint32_t image;         /* actual letter like a, b, c ... */
>             [...]
>     };
>
> fileio.c WriteFile():
>     for (i = 0; i < fore->w_height; i++) {
>             p = fore->w_mlines[i].image;
>             for (k = fore->w_width - 1; k >= 0 && p[k] == ' '; k--) ;
>             for (j = 0; j <= k; j++)
>                     putc(p[j], f);
>             putc('\n', f);
>     }
>
> This obviously doesn't work for characters > 255 which caused the
> garbled display for me.
>
>
> The attached patch should fix the issue. However somebody should
> verify my assumptions:
>
> I'm not 100% sure that ->image is actually the unicode code
> point.
>
> Double-width characters are followed by a character with ->image
> = 0xff and ->font = 0xff. I assumed that this means the character
> is a filler character to handle the fixed screen width correctly,
> but I'm not entirely sure. Is there a function/constant to check
> for fillers like this? Hard-coding 0xff doesn't sound like a good
> idea.
>
> I don't know how the fontp parameter of EncodeChar() is used:
>
>     int EncodeChar(char *bp, int c, int encoding, int *fontp)
>
> Passing NULL seems to work though.
>
> Regards
> Simon
>
> PS: The Git repository contains a lot of commits since the last
> release. A new release of GNU Screen sounds like a good idea to
> get those fixes/improvements distributed.
> --
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