signrs

Signrs is a digital signage player that is cross-platform, including low-power single-board computers like the Raspberry Pi. The player is a single executable that runs the developer's signage application.

This project is very heavily influenced by the awesome info-beamer project. It deviates in the following ways:

• Applications are built in JavaScript rather than Lua.
• The player runs on Windows, Linux, (and theoretically) macOS. Applications can be developed and tested on a desktop before being deployed to the signage hardware, e.g., a Raspberry Pi.
• Each player runs a webserver that allows making simple changes to the running app, and provides the API to create a player management tool.

example2.mp4

Key Missing Features

• Choosing an open-source license
• Parallelize drawing and JS engine to allow more complex applications to run at 60 FPS on resource-limited computers.
• Improve the web frontend to allow syncrhonizing updates to multiple players.
• Video playback

Running the Player

Build and run the player using cargo run --release <path to application>. Examples are in the examples directory, e.g.,:

cargo run --release examples/app2

To see the avaialable command-line arguments run:

cargo run --release -- --help

To view more debugging information, set the logging level with the RUST_LOG environment variable:

RUST_LOG=DEBUG cargo run examples/app2

To profile on Linux:

sudo sysctl -w kernel.perf_event_paranoid=-1
CARGO_PROFILE_RELEASE_DEBUG=true cargo flamegraph --flamechart --no-inline -- examples/app2

Creating an Application

Every application needs to have a "main.js" file, and export an init and draw function. The minimum application looks like this:

export function init() {
    set_resolution(960, 540);
}

export function draw(dt) {
    // Called once per frame with dt being the time between calls
    clear_screen(new Color(0, 0, 0));
}

Signage Application API

Drawing Classes

new Color(r, g, b, a=1)

new Font(fontPath)

new Image(imagePath)

Drawing Functions

clear_screen(color: Color)

Clears the drawing area and fills it with color.

draw_image(image: Image, x, y, width, height, alpha=1)

Draws an image with optional transparency.

draw_text(font: Font, text, x, y, size, color: Color)

Draws text.

size_text(font: Font, text, size)

Returns [width, height] of the sized text.

draw_rectangle(x, y, w, h, color: Color)

Draws a rectangle.

with_offset(x, y, callback)

Runs the callback with the coordinates of all drawing calls offset by (x, y).

Initialization Helpers

set_resolution(width, height)

Sets the resolution of the drawing area.

File Helpers

watch_json(jsonFilePath, callback(data), runFirst=true)

Creates a file watcher that runs immediately (if runFirst is true) and then whenever the file is changed. data is the JSON decoded data.