Howto:Hacking Inkscape to add Canvas support

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To create modern avionics, Inkscape is the most common tool these days, and is recommended not just for Canvas based displays, but also those using Phi [1]

Tom (Canvas) mentioned originally that for cockpit instruments using Inkscape with maybe a plugin will probably fit better.[2]

Inkscape’s extension architecture can be easily used with Python. There is also some support for other scripting languages. communications between inkscape and its extensions is fairly limited and can be made to easily work for simple command-line (CLI) appliications.

Background

Traditional Unix scripts can be used to extend Inkscape's functionality. Such programs read a stream of data on standard input, transform the data in some way, and then write the modified data to standard output. This is an easy way to expand Inkscape and provide custom functionality without learning the internals of Inkscape. Libraries for reading and writing SVG data exist for many programming languages, and most provide support for XML. This tutorial describes the "ins and outs" of writing one of these scripts and making it work with Inkscape's core functionality.

Inkscape couuld also be used to directly establish a "connection" with FlightGear (think telnet/props, httpd etc)

Extension types

The following extension types exist for Inkscape:

  • input (read a file / data)
  • output (write a file / data) (e.g. PropertyList/XML)
  • effect (change contents in the document)
  • print (output to an external device, this could be using fgfs itself)

Goals

Come up with a simple Inkscape extension that can serve as the foundation for creating Canvas based MFDs more easily. Ideally, in conjunction with Richard's MFD framework and the Emesary IPC system (eventually).

Integration

  • Canvas.Text
  • Canvas.Image
  • Canvas.Path
  • Canvas.Map (?)
  • MapStructure

SVG Events

Structure

Each MFD would be arranged using:

  • an outer shell for the UI
  • an inner region to display the Canvas serving as the screen

Python

WIP.png Work in progress
This article or section will be worked on in the upcoming hours or days.
See history for the latest developments.

Resources

Related

References
  1. Torsten  (Sep 22nd, 2014).  FGWebPanel aka FGPanel 2.0 or: FGPanel goes html .
  2. TheTom  (Jan 17th, 2013).  Re: Canvas custom GUI .