in reply to Re: GUI to dynamically show program output
in thread GUI to dynamically show program output

kcott, thank you very much!

The example really does what I need but unfortunately it doesn't show correctly the progress bar of the command. This is probably due to the fact that the textual progress bar includes a counter which is implemented by printing "\r" char (below the entire C function).

void doProgress(char* label, size_t step, size_t total) {
    //progress width
    const int pwidth = 60;

    //minus label len
    size_t width = pwidth - strlen(label);
    size_t pos = (step * width) / total;

    size_t percent = (step * 100) / total;

    printf("\r%s%4d/%4d [", label, step, total);

    int i;

    //fill progress bar with =
    for (i = 0; i < pos; i++) {
        printf("%c", '=');
    }

    //fill progress bar with spaces
    printf("% *c", width - pos + 1, ']');
    printf("%3d%%", percent);
    fflush(stdout);
}

[download]

The net result is that I get a mess displayed when I add the text to the TextView, because TextView doesn't interpret char escape sequences. I get the same result using Tk::DoCommand.

After a little bit of searching I think that I could probably solve the thing by using pseudo-ttys in Tk or even embedding Xterm(1) inside Tk !

The two examples are all in python, so I'd just ask if the same can be done with Perl Tk (maybe playing with IPC::Run module pseudo-ttys support) ?

Comments and further suggestions are always welcome!

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Re^3: GUI to dynamically show program output
by kcott (Archbishop) on Feb 05, 2021 at 07:00 UTC
    "... really does what I need but ... doesn't show correctly ... probably due to ... printing "\r" char ..."

    Well, I obviously had to make an initial guess about how the textual progressbar was implemented; however, you'll be glad to know that can be very easily fixed. :-)

    I rewrote the "Fill X" callback so that it gives a rough approximation of what your doProgress() is printing. I left in the all-important \r but didn't bother adding the percentage calculation. 

    $fill_x->configure(-command => sub {
    $_->configure(-state => 'disabled') for $fill_x, $fill_y;
    my $ms = 50 * (1 + int rand 10);
    my $iters = 1 + int rand 100;
    my $iter = 0;
    my $id;
    my $label = 'LABEL';
    $id = $mw->repeat($ms, sub {
        if (++$iter <= $iters) {
            text_show($text,
                sprintf "\r%s%4d/%4d [%s]",
                    $label, $iter, $iters, '=' x $iter
            );
        }
        else {
            text_show($text, "\nDone!\n");
            $id->cancel;
            $_->configure(-state => 'normal') for $fill_x, $fill_y;
        }
    });
});

    [download]

    I then added some code to text_show() to handle the \r. 

    {
    my ($line, $char); BEGIN { ($line, $char) = (1, 0) }

    sub text_show {
        my ($text, $str) = @_;

        if (0 == index $str, "\r") {
            $str = substr $str, 1;
            $text->delete("$line.0", "$line.$char");
            $char = 0;
        }

        $text->insert("$line.$char" => $str);

        if (-1 < index $str, "\n") {
            $line += $str =~ y/\n//;
            $char = length(substr $str, rindex $str, "\n") - 1;
        }
        else {
            $char += length $str;
        }

        $text->see("$line.$char");
    }
}

    [download]

    You may notice that I also moved the $text->see("$line.$char") statement. It logically makes more sense for this to occur after $line and $char have been recalculated; although, visually I couldn't see any difference. It probably depends on the size of the GUI window, how you've implemented scrollbars, and the value of -wrap. I'll leave you to play around with that part.

    I didn't change anything else in the original code I posted. So, just change those two blocks of code; give it a whirl; and see how you go.

    Minor update: With the numbers being displayed, I noticed an off-by-one error in the "Fill X" callback: I changed ++$iter < $iters to ++$iter <= $iters. The same error exists in the "Fill Y" callback: fix it if you want; it would only be noticeable if $iters randomised to 1, in which case you'd get no output.

    — Ken

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