Is this the wrong way to use writeCell()?

[treeshateorcs]

Here's what I do:

vx.screen.writeCell(@intCast(x), @intCast(y), Cell{ .char = Cell.Character{ .grapheme = &[1]u8{'a'}, .width = 1 } });

and here's the full code

const std = @import("std");
const vaxis = @import("vaxis");
const Cell = vaxis.Cell;

const Event = union(enum) {
    key_press: vaxis.Key,
    winsize: vaxis.Winsize,
    focus_in,
    foo: u8,
};

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer {
        const deinit_status = gpa.deinit();
        if (deinit_status == .leak) {
            std.log.err("memory leak", .{});
        }
    }
    const alloc = gpa.allocator();
    var tty = try vaxis.Tty.init();
    defer tty.deinit();
    var vx = try vaxis.init(alloc, .{});
    defer vx.deinit(alloc, tty.anyWriter());
    var loop: vaxis.Loop(Event) = .{
        .tty = &tty,
        .vaxis = &vx,
    };
    try loop.init();
    try loop.start();
    defer loop.stop();
    try vx.enterAltScreen(tty.anyWriter());
    try vx.queryTerminal(tty.anyWriter(), 1 * std.time.ns_per_s);

    var x = vx.window().width;
    var y = vx.window().height;
    while (true) {
        const event = loop.nextEvent();
        switch (event) {
            .key_press => |key| {
                if (key.matches('c', .{ .ctrl = true })) {
                    break;
                } else if (key.matches('l', .{ .ctrl = true })) {
                    vx.queueRefresh();
                }
            },
            .winsize => {
                std.process.exit(1);
            },
            else => {},
        }
        while (x != 0) {
            while (y != 0) {
                vx.screen.writeCell(@intCast(x), @intCast(y), Cell{ .char = Cell.Character{ .grapheme = &[1]u8{'a'}, .width = 1 } });
                y -= 1;
            }
            x -= 1;
        }
        try vx.render(tty.anyWriter());
    }
}

New to Zig, sorry for the noob question!

[rockorager]

while (x != 0) { while (y != 0) { ***@***.***(x), @intcast(y), Cell{ .char = Cell.Character{ .grapheme = &[1]u8{'a'}, .width = 1 } }); y -= 1; } x -= 1; }

When you use the syntax `&[1]u8{'a'}`, this creates a reference to an array of length one and contents 'a'. The lifetime of this reference is tied to the lifetime of the array, which in this case is scoped to the inner while loop. As soon as the inner loop moves to the next iteration, the reference is gone - and you are likely seeing bogus output. If you have *static* strings, you can do `.grapheme = "a"`. If you have dynamic strings, you need to do something to make sure their lifetime extends to after your call to `vx.render` finishes.

[treeshateorcs]

thank you so much for the elaborate answer!

when i do .grapheme = "a" it doesn't change much, the behaviour is the same, it doesn't print anything in the terminal

[rockorager]

You need to handle the winsize event. call vx.resize with it.

[treeshateorcs]

omg finally i have solved it, i've been banging my head against the wall for an hour or more

for some reason it didn't work with a while loop, but when i switched to for it worked flawlessly, here's the final version of the outer while loop

    while (true) {
        const event = loop.nextEvent();
        switch (event) {
            .key_press => |key| {
                if (key.matches('c', .{ .ctrl = true })) {
                    break;
                } else if (key.matches('q', .{})) {
                    break;
                } else if (key.matches('l', .{ .ctrl = true })) {
                    vx.queueRefresh();
                }
            },
            .winsize => |ws| {
                try vx.resize(alloc, tty.anyWriter(), ws);
            },
            else => {},
        }
        for (0..vx.screen.width) |i| {
            for (0..vx.screen.height) |j| {
                const cell: Cell = .{
                    .char = .{ .grapheme = "a" },
                };
                vx.screen.writeCell(@intCast(i), @intCast(j), cell);
            }
        }
        try vx.render(tty.anyWriter());
    }

[rockorager]

Glad it's working!

I would take a look at the vx.window() call and associated Window methods. They provided some nice helpers for writing to the screen.

[treeshateorcs]

is there any way to exit on window resize, like i wrote in my first post? (at least that was my intention)

[rockorager]

You could try exiting on the second one received. The Loop implementation always sends one as the first event so that you know the initial window size. Subsequent events are from resizes. I wouldn’t call this reliable though.

[treeshateorcs]

thanks!