Subj : Custom Scrollabe Text Fil
To   : All
From : Codefenix
Date : Tue Nov 05 2024 18:38:00

As discussed in Synchronet Discussion, I wanted a viewer for text files with a scrollable interface.

This is the one that I came up with. Some parts I lifted from other modules to try to understand how frames and scrollbars work. It works, but it's far from perfect. I plan to use it in conjunction with some other mods that I tinker with (news readers, inter-bbs one-liner history, etc) as well as general text files.

Here's a demo of me using it in my modified General Text Files section:
 https://conchaos.synchro.net/img/viewfile_demo.gif

It uses a frame object to display the text, but I'm starting to think that's not the best idea. Some files take a long time to load, and files no larger than 117 KB can lead to "out of memory" errors. Getting the impression frames weren't meant for "large" objects, so maybe there's a better way.

Anyone who wants to try it is more than welcome. Just be aware it may not give optimal results for now.

// viewfile.js ============================================= start //

load("sbbsdefs.js");
load("frame.js");
load("scrollbar.js");

const OPTIONS = " " + ascii(24) + " / " + ascii(25) +
                " / pg-up / pg-dn / home / end / q: quit";

function init_display() {
    const w = console.screen_columns;
    const h = console.screen_rows;
    const f = { top: new Frame(1, 1, w, h, BG_BLACK|LIGHTGRAY) };
    f.topbar = new Frame(1, 1, w, 1, BG_LIGHTGRAY|BLACK, f.top);
    f.output = new Frame(1, 2, w, h - 2, BG_BLACK|LIGHTGRAY, f.top);
    f.bottombar = new Frame(1, h, w, 1, BG_LIGHTGRAY|BLACK, f.top);
    f.output_scroll = new ScrollBar(f.output, { autohide: true });
    f.output.word_wrap = true;
    f.bottombar.putmsg(OPTIONS);
    f.top.open();
    return f;
}

function main(file_name, file_title, scroll_to_top) {
    var title = file_title ? file_title : file_getname(file_name);
    var exit_viewer = false;
    var key_pressed;
    const frames = init_display();
    if (file_exists(file_name)) {
        log(LOG_INFO, "Loading " + title);
        frames.topbar.putmsg("Loading " + title.substr(0, 65) + "...");
        frames.top.cycle();
        //frames.output.load(file_name); /* Issues with frame load():
                                       // Seems slow; eg: 4 secs to load 49 KB.
                                       // "out of memory" error loading 219 KB.
                                       // "out of memory" error loading 117 KB.
                                       // Not all extension types supported.

        var txt = new File(file_name); // Trying this as an alternative..
        if (txt.open("r")) {           // ... but still slow. :(
            frames.output.putmsg(strip_ansi(txt.read()).replace(/\f/g, ""));
            txt.close();
        }

        if (scroll_to_top) {
            frames.output.scrollTo(0, 0);
        }
        frames.output_scroll.cycle();
        log(LOG_INFO, "Done loading: " + title);
        frames.top.cycle();
        frames.topbar.clear();
        frames.topbar.putmsg("Viewing: " + title.substr(0, 70));
        frames.top.cycle();
        frames.output_scroll.cycle();
        while (!js.terminated && !exit_viewer) {
            frames.output_scroll.cycle();
            key_pressed = console.inkey(K_NONE, 5).toUpperCase();
            if (key_pressed == KEY_UP && frames.output.offset.y > 0) {
                frames.output.scroll(0, -1);
            } else if (key_pressed == KEY_DOWN && (frames.output.offset.y +
                       frames.output.height) < frames.output.data_height) {
                frames.output.scroll(0, 1);
            } else if (key_pressed == KEY_PAGEUP &&
                       frames.output.offset.y > 0 ) {
                frames.output.scroll(0, -1 * frames.output.height);
            } else if (key_pressed == KEY_PAGEDN && (frames.output.offset.y +
                       frames.output.height) < frames.output.data_height) {
                frames.output.scroll(0, frames.output.height);
            } else if (key_pressed == KEY_HOME) {
                frames.output.scrollTo(0, 0);
            } else if (key_pressed == KEY_END) {
                frames.output.scrollTo(0, frames.output.data_height -
                                          frames.output.height - 1);
            } else if (key_pressed == "Q") {
                exit_viewer = true;
            }
            frames.output_scroll.cycle();
            frames.top.cycle();
        }
        frames.top.close();
        print("\x01q\x01l\x01n");
    } else {
        log(LOG_ERROR, "File not found: " + file_name);
    }
}

// 1: file path (string)
// 2: title (string)
// 3: start from top (boolean; default is false)
main(argv[0], argv[1], argv[2]);

// viewfile.js ============================================= end //

|15 þ ù ú codefenix ú ù ú ConstructiveChaos BBS ú ú ù þ þ
|08 þ þ ù (https/telnet/ssh)://conchaos.synchro.net ú ù þ
|07

....A fool must now and then be right by chance.
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