eliath / display

Lightweight browser-based display server

display: a browser-based graphics server

Originally forked from gfx.js.

The initial goal was to remain compatible with the torch/python API of gfx.js, but remove the term.js/tty.js/pty.js stuff which is served just fine by ssh.

Compared to gfx.js:

• no terminal windows (no term.js)
• dygraphs instead of nvd3 (have built in zoom and are perfect for time-series plots)
• plots resize when windows are resized
• images support zoom and pan
• image lists are rendered as one image to speed up loading
• windows remember their positions
• implementation not relying on the filesystem, supports remote clients (sources)

Technical overview

The server is a trivial message forwarder:

POST /events -> EventSource('/events')

The Lua client sends JSON commands directly to the server. The browser script interprets these commands, e.g.

{ command: 'image', src: 'data:image/jpg;base64,....', title: 'lena' }

Supported commands

Common parameters:

• win: identifier of the window to be reused (pick a random one if you want a new window)
• title: title for the window title bar

image creates a zoomable <img> element

• src: URL for the <img> element
• width: initial width in pixels
• zoom: zoom in/out the canvas, with linear interpolation (useful to zoom in small filters/pictures)
• labels: array of 3-element arrays [ x, y, text ], where x, y are the coordinates (0, 0) is top-left, (1, 1) is bottom-right; text is the label content

plot creates a Dygraph, all Dygraph options are supported

• file: see Dygraph data formats for supported formats
• labels: list of strings, first element is the X label

Installation and usage

Install:

luarocks make

Launch the server:

~/.display/run.js &
# or simply load display in th:
th
> d = require 'display'

Note, there is no authentication and by default the server listens on external IP (port 8000), so don't use "as is" for sensitive data.

See example.lua for sample usage.

local disp = require 'display'
disp.image(image.lena())
disp.plot(torch.cat(torch.linspace(0, 10, 10), torch.randn(10), 2))