simulate-lcd

A simple library to simulate monochrome dot-matrix displays, such as monochrome LCD screens.

Documentation

Example

use std::{thread::sleep, time::Duration};

use rand::{thread_rng, Rng};
use sdl2::event::Event;
use simulate_lcd::{Bitmap, LcdScreen}
use simulate_lcd::{LCD_DARK_GREEN, LCD_LIGHT_GREEN};

const NANOS_PER_SEC: u64 = 1_000_000_000;

fn main() {
    let sdl_context = sdl2::init().unwrap();
    let mut screen = LcdScreen::<64, 96>::new(
        &sdl_context,
        "LCD Demo: Random",
        LCD_DARK_GREEN,
        LCD_LIGHT_GREEN,
        10,
        10,
    )
    .unwrap();

    let mut event_pump = sdl_context.event_pump().unwrap();
    'running: loop {
        for event in event_pump.poll_iter() {
            match event {
                Event::Quit { .. } => break 'running,
                _ => {}
            }
        }

        let mut rng = thread_rng();
        let random_bits: Vec<[bool; 96]> = (0..64)
            .map(|_| rng.gen())
            .collect();
        screen.draw_bitmap(&random_bits.try_into().unwrap())
            .unwrap();

        sleep(Duration::new(0, NANOS_PER_SEC / 60));
    }
}

More examples can be found in the examples folder.

Usage

LcdScreen is the main type provided by this crate. To create new simulated screen window with R rows and C columns of dots, use the function LcdScreen::<R, C>::new, with the following parameters:

• sdl_context: an Sdl context object
• title: the window title
• on_color: the color of a dot when it is 'on'. e.g. (near) black on a backlight LCD screen
• off_color: the color of a dot when it is 'off'. e.g. green on a green backlight LCD screen
• dot_width: the width of a dot in pixels of the actual window
• dot_height: the height of a dot in pixels of the actual window

The screen will disappear as soon as the LcdScreen object is dropped, including at the end of the scope it was created. Use a loop, or some other device, to stop the screen object from being dropped.

New images can be drawn to the screen using the draw_bitmap method. draw_bitmap takes any object which can be converted into a [[bool;C];R] array. Each true in this row-major array represents a dot that is 'on'. simulate-lcd offers Bitmap<C, R> as a convenient alias for [[bool;C];R].

The 'on' and 'off' colors of the screen are sdl2::pixels::Color objects. They can be created from RGB values with the sdl2::pixels::Color::RGB function. simulate-lcd offers the LCD_DARK_GREEN and LCD_LIGHT_GREEN constants from simulating green backlight LCD screens.

Setup

simulate-lcd is built around the sdl2 crate. A new LcdScreen requires an Sdl context object created by the sdl2::init() function. Note that sdl2 may require further setup than just adding the crate. See the sdl2 README for details.

License

Licensed under the Apache License, Version 2.0 (LICENSE or http://www.apache.org/licenses/LICENSE-2.0).