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

[Simon Ruderich]

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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