AnyViewer - a programmable desktop file viewer built on Electron

AnyViewer is a desktop application to view files, built on Electron. The application only displays HTML, so AnyViewer needs to be programmed to convert arbitrary files into HTML format, using a plugin.

AnyViewer ships with plugins to handle Markdown, and source files that can be rendered by the highlight.js package (the list of languages is available here).

AnyViewer viewing it's own README.md

AnyViewer viewing one of it's JavaScript source files

features

• Font-size changes can be made via menu and shortcuts, the same way you change "zoom" pages in the Chrome web browser. The last change you made is set as the default size for all future viewer windows.

• The last change you made to the height and width of the windows are set as the default values for all future viewer windows.

• A file which is being viewed is tracked for changes; when the file changes on disk, the view will be reloaded with the new contents.

• Print files with background colors and images, with a font-size that renders the text fairly readable on a tablet when printed to PDF file.

• You can open a Chrome Dev Tools window via menu and shortcut, if you like to or need to peek behind the curtains.

install

You can download a pre-built binary from the releases page.

Mac OS X notes

Unzip the archive, and move the resulting AnyViewer.app folder to an appropriate location.

AnyViewer associates itself with .md files when installed. So, you can:

• double-click an .md file from Finder
• run open someFileName.md from the Terminal
• drag / drop a file from Finder onto an AnyViewer icon in your Dock

Once open, you can open other viewer windows through the File / Open File ... menu item.

You can associate AnyViewer with other file extensions, by following these instructions.

Windows notes

Windows builds are not tested, they are the build outputs of electron-packager. Please create an issue for problems encountered.

Linux notes

Linux builds are not tested, they are the build outputs of electron-packager. Please create an issue for problems encountered.

plugins

In order to have a custom HTML renderer for a particular file extension, you'll need to install a plugin. A plugin is a node package installed in a particular location. That location is the directory named plugins in the AnyViewer data directory. The AnyViewer data directory in your home directory, named .AnyViewer, and stores other preference-y data.

Each plugin should be in a separate directory, in the same vein as node's node_modules directory. The package.json file for each package should have a property: AnyViewer, whose value is an object (described below), but otherwise should be an npm-installable package. Packages without an AnyViewer property are not considered plugins.

The AnyViewer object in a package.json file should be an object, and can have the following properties:

• plugin: the value of this property should be a reference to a module moduleID that is the primary entrypoint to the plugin. Very similar to package.json's main.

The plugin's primary entrypoint should be a module which exports the following properties:

• toHTML: a function of shape toHTML(vinylIn, vinylOut, cb). This function is invoked to convert the original file being opened to HTML. The vinyl* parameters are vinyl File objects, probably just with the file name values.

  • vinylIn is the file that was requested to be open.
  • vinylOut is an output file which will be rendered in the HTML viewer - so it should be HTML. The plugin is expected to write the HTML content to the specified file name.
  • The cb parameter is a callback of the shape cb(err). Invoked this function when you have finished writing the HTML back, passing null as err on success, else an Error object.

  The path set in vinylOut is a temporary file name, which you can use to generate HTML into. The file will be erased when the viewer window closes.

• extensions: an array of strings of extensions supported by this plugin. Should not include the "." character at the beginning of each string, unlike vinyl's extname property. You can provide "multi-part" extensions, so for instance the extension array could be ["foo.md"], which would indicate that files of the form *.foo.md would be handled by the plugin. In the case of two plugins, one handling ["foo.md"] and one handling ["md"], the one with the most "parts" in it wins - "foo.md" in this case.

sample plugin

By default, AnyViewer will view .html files with syntax highlighting of the HTML source.

Described below is a sample plugin which overrides that viewer, with one that renders the HTML as a web page.

It's not terribly practical - this plugin does not fix relatively referenced resources (images, css files, etc), so those files won't be loaded when the HTML is rendered in Anyviewer. But, it's a simple example.

These files should be stored in the directory ~/.AnyViewer/plugins/avpi-html (in your home directory).

file package.json

{
  "name":         "avpi-html",
  "description":  "AnyViewer plugin for HTML",
  "AnyViewer": {
    "plugin":     "./plugin"
  }
}

file plugin.js

const fs = require("fs")

exports.toHTML     = toHTML
exports.extensions = ["html"]

function toHTML(iVinyl, oVinyl, cb) {
  const content = fs.readFileSync(iVinyl.path, "utf8")
  fs.writeFileSync(oVinyl.path, content)

  cb()
}

building

• clone this repo
• run npm install to install dependencies
• run npm run build to build the execute

Executables and archives for all platforms will be in the build directory.

hacking

This project uses cake as it's build tool. To rebuild the project continuously, use the command

npm run watch

Other cake commands are available (assuming you are using npm v2) with the command

npm run cake -- <command here>

Run npm run cake to see the other commands available in the Cakefile.

contributing

Awesome! We're happy that you want to contribute.

Make sure that you're read and understand the Code of Conduct.

license

The AnyViewer specific code in this application is licensed under the Apache License, Version 2.0. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0