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102 lines
4.3 KiB
Markdown
102 lines
4.3 KiB
Markdown
## `term.ui`
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A V module for designing terminal UI apps
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#### Quickstart
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```v
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import term.ui as tui
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struct App {
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mut:
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tui &tui.Context = 0
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}
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fn event(e &tui.Event, x voidptr) {
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mut app := &App(x)
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println(e)
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}
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fn frame(x voidptr) {
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mut app := &App(x)
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app.tui.clear()
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app.tui.set_bg_color(r: 63, g: 81, b: 181)
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app.tui.draw_rect(20, 6, 41, 10)
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app.tui.draw_text(24, 8, 'Hello from V!')
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app.tui.set_cursor_position(0, 0)
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app.tui.reset()
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app.tui.flush()
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}
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mut app := &App{}
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app.tui = tui.init(
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user_data: app,
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event_fn: event,
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frame_fn: frame
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hide_cursor: true
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)
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app.tui.run()
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```
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See the `/examples/term.ui/` folder for more usage examples.
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#### Configuration
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- `user_data voidptr` - a pointer to any `user_data`, it will be passed as the last argument to
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each callback. Used for accessing your app context from the different callbacks.
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- `init_fn fn(voidptr)` - a callback that will be called after initialization
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and before the first event / frame. Useful for initializing any user data.
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- `frame_fn fn(voidptr)` - a callback that will be fired on each frame,
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at a rate of `frame_rate` frames per second.
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`event_fn fn(&Event, voidptr)` - a callback that will be fired for every event received.
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- `cleanup_fn fn(voidptr)` - a callback that will be fired once, before the application exits.
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- `fail_fn fn(string)` - a callback that will be fired
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if a fatal error occurs during app initialization.
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- `buffer_size int = 256` - the internal size of the read buffer.
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Increasing it may help in case you're missing events, but you probably shouldn't lower
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this value unless you make sure you're still receiving all events. In general,
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higher frame rates work better with lower buffer sizes, and vice versa.
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- `frame_rate int = 30` - the number of times per second that the `frame` callback will be fired.
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30fps is a nice balance between smoothness and performance,
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but you can increase or lower it as you wish.
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- `hide_cursor bool` - whether to hide the mouse cursor. Useful if you want to use your own.
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- `capture_events bool` - sets the terminal into raw mode, which makes it intercept some
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escape codes such as `ctrl + c` and `ctrl + z`.
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Useful if you want to use those key combinations in your app.
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- `window_title string` - sets the title of the terminal window.
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This may be changed later, by calling the `set_window_title()` method.
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- `reset []int = [1, 2, 3, 4, 6, 7, 8, 9, 11, 13, 14, 15, 19]` - a list of reset signals,
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to setup handlers to cleanup the terminal state when they're received.
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You should not need to change this, unless you know what you're doing.
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All of these fields may be omitted, in which case, the default value will be used.
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In the case of the various callbacks, they will not be fired if a handler has not been specified.
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#### FAQ
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Q: Why does this module not work on Windows?
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A: As with many other things, Windows has a completely different and incompatible way of handling
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input parsing and drawing primitives, and support has not been implemented yet.
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Contributions are definitely welcome though.
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Q: My terminal (doesn't receive events / doesn't print anything / prints gibberish characters),
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what's up with that?
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A: Please check if your terminal. The module has been tested with `xterm`-based terminals on Linux
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(like `gnome-terminal` and `konsole`), and `Terminal.app` and `iterm2` on macOS.
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If your terminal does not work, open an issue with the output of `echo $TERM`.
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Q: There are screen tearing issues when doing large prints
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A: This is an issue with how terminals render frames,
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as they may decide to do so in the middle of receiving a frame,
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and cannot be fully fixed unless your console implements the [synchronized updates spec](https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec).
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It can be reduced *drastically*, though, by using the rendering methods built in to the module,
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and by only painting frames when your app's content has actually changed.
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Q: Why does the module only emit `keydown` events, and not `keyup` like `sokol`/`gg`?
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A: It's because of the way terminals emit events. Every key event is received as a keypress,
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and there isn't a way of telling terminals to send keyboard events differently,
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nor a reliable way of converting these into `keydown` / `keyup` events.
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