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# libvaxis
```
It begins with them, but ends with me. Their son, Vaxis
```
libvaxis is a zig port of the go TUI library
[Vaxis](https://git.sr.ht/~rockorager/vaxis). The goal is to have the same
feature set, only written in zig.
Like it's sibling library, libvaxis _does not use terminfo_. Support for vt
features is detected through terminal queries.
Contributions are welcome.
## Feature comparison
| Feature | Vaxis | libvaxis | notcurses |
| ------------------------------ | :---: | :------: | :-------: |
| RGB | ✅ | ✅ | ✅ |
| Hyperlinks | ✅ | planned | ❌ |
| Bracketed Paste | ✅ | planned | ❌ |
| Kitty Keyboard | ✅ | ✅ | ✅ |
| Styled Underlines | ✅ | ✅ | ✅ |
| Mouse Shapes (OSC 22) | ✅ | planned | ❌ |
| System Clipboard (OSC 52) | ✅ | planned | ❌ |
| System Notifications (OSC 9) | ✅ | planned | ❌ |
| System Notifications (OSC 777) | ✅ | planned | ❌ |
| Synchronized Output (DEC 2026) | ✅ | ✅ | ✅ |
| Unicode Core (DEC 2027) | ✅ | ✅ | ❌ |
| Color Mode Updates (DEC 2031) | ✅ | planned | ❌ |
| Images (full/space) | ✅ | planned | ✅ |
| Images (half block) | ✅ | planned | ✅ |
| Images (quadrant) | ✅ | planned | ✅ |
| Images (sextant) | ❌ | ❌ | ✅ |
| Images (sixel) | ✅ | planned | ✅ |
| Images (kitty) | ✅ | planned | ✅ |
| Images (iterm2) | ❌ | ❌ | ✅ |
| Video | ❌ | ❌ | ✅ |
| Dank | 🆗 | 🆗 | ✅ |
## Usage
The below example can be run using `zig build run 2>log`. stderr must be
redirected in order to not print to the same screen.
```zig
const std = @import("std");
const vaxis = @import("vaxis");
const Cell = vaxis.Cell;
const TextInput = vaxis.widgets.TextInput;
const border = vaxis.widgets.border;
const log = std.log.scoped(.main);
// Our EventType. This can contain internal events as well as Vaxis events.
// Internal events can be posted into the same queue as vaxis events to allow
// for a single event loop with exhaustive switching. Booya
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();
//fail test; can't try in defer as defer is executed after we return
if (deinit_status == .leak) {
log.err("memory leak", .{});
}
}
const alloc = gpa.allocator();
// Initialize Vaxis with our event type
var vx = try vaxis.init(Event, .{});
// deinit takes an optional allocator. If your program is exiting, you can
// choose to pass a null allocator to save some exit time.
defer vx.deinit(alloc);
// Start the read loop. This puts the terminal in raw mode and begins
// reading user input
try vx.startReadThread();
defer vx.stopReadThread();
// Optionally enter the alternate screen
try vx.enterAltScreen();
// We'll adjust the color index every keypress for the border
var color_idx: u8 = 0;
// init our text input widget. The text input widget needs an allocator to
// store the contents of the input
var text_input = TextInput.init(alloc);
defer text_input.deinit();
// Sends queries to terminal to detect certain features. This should
// _always_ be called, but is left to the application to decide when
try vx.queryTerminal();
// The main event loop. Vaxis provides a thread safe, blocking, buffered
// queue which can serve as the primary event queue for an application
outer: while (true) {
// nextEvent blocks until an event is in the queue
const event = vx.nextEvent();
log.debug("event: {}\r\n", .{event});
// exhaustive switching ftw. Vaxis will send events if your EventType
// enum has the fields for those events (ie "key_press", "winsize")
switch (event) {
.key_press => |key| {
color_idx = switch (color_idx) {
255 => 0,
else => color_idx + 1,
};
if (key.matches('c', .{ .ctrl = true })) {
break :outer;
} else if (key.matches('l', .{ .ctrl = true })) {
vx.queueRefresh();
} else {
try text_input.update(.{ .key_press = key });
}
},
// winsize events are sent to the application to ensure that all
// resizes occur in the main thread. This lets us avoid expensive
// locks on the screen. All applications must handle this event
// unless they aren't using a screen (IE only detecting features)
//
// This is the only call that the core of Vaxis needs an allocator
// for. The allocations are because we keep a copy of each cell to
// optimize renders. When resize is called, we allocated two slices:
// one for the screen, and one for our buffered screen. Each cell in
// the buffered screen contains an ArrayList(u8) to be able to store
// the grapheme for that cell Each cell is initialized with a size
// of 1, which is sufficient for all of ASCII. Anything requiring
// more than one byte will incur an allocation on the first render
// after it is drawn. Thereafter, it will not allocate unless the
// screen is resized
.winsize => |ws| try vx.resize(alloc, ws),
else => {},
}
// vx.window() returns the root window. This window is the size of the
// terminal and can spawn child windows as logical areas. Child windows
// cannot draw outside of their bounds
const win = vx.window();
// Clear the entire space because we are drawing in immediate mode.
// vaxis double buffers the screen. This new frame will be compared to
// the old and only updated cells will be drawn
win.clear();
const child = win.initChild(
win.width / 2 - 20,
win.height / 2 - 3,
.{ .limit = 40 },
.{ .limit = 3 },
);
// draw the text_input using a bordered window
const style: vaxis.Style = .{
.fg = .{ .index = color_idx },
};
text_input.draw(border.all(child, style));
// Render the screen
try vx.render();
}
}
```