Got an idea on how to improve Vizanti?
Contrbutions are of course welcome, feel free to fork and submit PRs for any fixes or extra widgets you find useful.
Vizanti is split into the python based ROS-side server and the web browser client.
The static content is served using Flask, with Jinja2 as the template engine. ROS related communications go through Rosbridge and Rosapi.
There are also two ROS nodes that provide additional functionality not covered by Rosbridge.
The front end is written in vanilla JS with ES6 modules, while making use of Jinja templating and minimal fixed dependencies in vizanti_server/public/js/lib.
Upon client load, the server collects all widget templates in vizanti_server/public/templates and sends them to the client where they are processed by main.js. As per the existing examples, the suported files are:
-
name_icon.htmlThe mandatory icon element that will be added to the taskbar. -
name_modal.htmlA popup window element that is used to select the topic and change any settings. -
name_view.htmlA canvas layer for drawing visualizers. Define the Z-order value so that your element is rendered in the right order. Canvases of the same type of widget will be rendered in the order they were added. -
name_script.jsA JS module that can import helper singletons from vizanti_server/public/js/modules.
To add the widget to the taskbar, it has to be defined in the add_types_container list in the add_modal.html. The data-topic value is used for creating widgets from a specific topic.
Any required assets should be put into vizanti_server/public/assets.
Every widget should have the string "{uniqueID}" embedded in its code, which will be replaced with a unique sequential identifier (e.g. "auto53") at widget instantiation, so all of those scattered elements above can have direct references to each other and a unique tag for saving settings.
As an example:
//battery_icon.html
<div id="{uniqueID}_icon" class="icon noselect">
<img src="assets/battery_unknown.svg" alt="?" width="50" height="50" onclick="openModal('{uniqueID}_modal')">
</div> Which can then be obtained from the script as follows:
//battery_script.html
const icon = document.getElementById("{uniqueID}_icon");
icon.src = "something.png"Quaternion.js and Roslib.js are loaded globally. There are also two global functions to streamline opening and closing models, the aptly named openModal(widget_id+"_modal") and closeModal(widget_id+"_modal") found in setup.js. Typically called when an icon is clicked.
let viewModule = await import(`${base_url}/js/modules/view.js`);
let view = viewModule.view;Handles how the screen is moved and zoomed by the user for final rendering from ROS tf space into screen space. The TF and screen frames are currently not rotated, which simplifies rendering.
Example:
const img_width = view.getMapUnitsInPixels(width_meters);
const img_height = view.getMapUnitsInPixels(length_meters);
let pos = view.fixedToScreen({
x: object.translation.x,
y: object.translation.y,
});
ctx.translate(pos.x, pos.y);
ctx.drawImage(img, -img_width/2, -img_height/2, img_width, img_height);It fires off events when the screen is updated as a rendering callback.
window.addEventListener("view_changed", drawWidget);let tfModule = await import(`${base_url}/js/modules/tf.js`);
let tf = tfModule.tf;An implementation of the TF graph that gets grouped TF data at 30 fps from the/vizanti/tf_consolidated topic.
Example:
//global rendering frame, as selected in global options
tf.fixed_frame
//absoluteTransforms provides all known frames transformed to the global fixed frame for quick rendering
const absolute_frame = tf.absoluteTransforms["base_link"];
absolute_frame.translation // Vector3
absolute_frame.rotation // Quaternion
//getting the radians yaw for top down rendering
let yaw = absolute_frame.rotation.toEuler().h;
//transforms provides the relative parent-child transforms as given by TF
const relative_frame = tf.transforms["base_link"];
relative_frame.parent //"odom", most likelyLike the view, it fires off events when the screen is updated as a rendering callback.
window.addEventListener("tf_changed", drawWidget);let rosbridgeModule = await import(`${base_url}/js/modules/rosbridge.js`);
let rosbridge = rosbridgeModule.rosbridge;Wrapper for roslib.js, used for communicating with ROS.
Example:
//all running nodes
let nodes = await rosbridge.get_all_nodes();
//all topics
let topics = await rosbridge.get_all_topics();
//all topics of specified type
let specific_topics = await rosbridge.get_topics("sensor_msgs/NavSatFix");
//built in function to get the topic name passed by the widget creator
let topic = getTopic("{uniqueID}");
roslib_topic = new ROSLIB.Topic({
ros : rosbridge.ros,
name : topic,
messageType : 'sensor_msgs/LaserScan',
throttle_rate: 30, //minium ms between messages, alleviates congestion but does not guarantee that all messages will be received
compression: "cbor" //compression for higher throughput topics
});
listener = roslib_topic.subscribe((msg) => {
console.log(msg.data)
});let persistentModule = await import(`${base_url}/js/modules/persistent.js`);
let settings = persistentModule.settings;Provides a localStorage object for saving widget settings.
Example:
//if there's saved data, we fetch it upon module load
if(settings.hasOwnProperty("{uniqueID}")){
const loaded_data = settings["{uniqueID}"];
topic = loaded_data.topic;
something = loaded_data.something;
checkbox.checked = loaded_data.checkbox;
}
function saveSettings(){
settings["{uniqueID}"] = {
topic: topic,
something: input.value,
checkbox: checkbox.checked
}
settings.save();
}
//on input change
saveSettings();let utilModule = await import(`${base_url}/js/modules/util.js`);
let imageToDataURL = utilModule.imageToDataURL;The util class provides utility functions, the only one right now being imageToDataURL for persistent image loading that doesn't trigger new server requests upon changing an Image .src param.
const persistent_image = await imageToDataURL("assets/image.svg");let StatusModule = await import(`${base_url}/js/modules/status.js`);
let Status = StatusModule.Status;A helper class that emulates the status indicator from rviz for each widget.
First, add this element to the widget's modal, the current convention is directly below the title text.
<p id="{uniqueID}_status" class="status">Status: Ok.</p>Then instantiate the class and pass it the icon and status elements:
//by default the status is "Ok" as defined in the html
let status = new Status(
document.getElementById("{uniqueID}_icon"),
document.getElementById("{uniqueID}_status")
);
//show an errpr
status.setError("Empty topic.");
//show a warning
status.setWarn("No data received.");
//everything should be working fine
status.setOK();let joystickModule = await import(`${base_url}/js/modules/joystick.js`);
let nipplejs = joystickModule.nipplejs;Joystick.js is a module wrapper for nipple.js. Example usage in teleop:script.js
let navsatModule = await import(`${base_url}/js/modules/navsat.js`);
let navsat = navsatModule.navsat;A module for downloading, storing, and loading slippy map tiles, mainly for use in satelite_script.js.
Example:
const tileURL = "https://tile.openstreetmap.org/19/123/254.png"
let tileImage = navsat.live_cache[tileURL];
//could be a placeholder if we're still loading, or not downloaded yet, in which case fetch it
if(!tileImage || !tileImage.complete){
tileImage = placeholder;
navsat.enqueue(tileURL);
}
//lattitude and longitude to coordinate tile indices
let tile_coords = navsat.coordToTile(longitude, latitude, zoomLevel)
//and the reverse, gets the bottom left corner of the tile
let tile_fix = navsat.tileToCoord(x, y, zoomLevel);
//distance between two points on a sphere
let distance_meters = navsat.haversine(latitude_a, longitude_a, latitude_b, longitude_b);More general info:
https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
https://github.com/nobleo/rviz_satellite