JavaScript InfoVis Toolkit ability to handle high volume of data - javascript

Does anyone have experience displaying large set of data using JavaScript InfoVis Toolkit? Basically, I am doing research on how my project can provide visual representation of social network... and playing around with JavaScript InfoVis Toolkit I did not notice any performance degradation... meanwhile I saw this:
JavaScript InfoVis Toolkit - interaction seems a little slow, maybe that's on purpose in the demos from
javascript framework for relationship visualization
and
JsVIS is pretty nice, but a little slow with larger graphs. from
Graph visualization library in JavaScript
this makes me worry that under real data it might crack? So just asking..
plus i looked at Flare, it seems like another good alternative, but looking at their site it looks like it hasn't been updated in almost 2 years... is it totally outdated?

To answer my own question.... performance is not that great. I wrote a script to populate json object used in ForceDirected object with 100 nodes and it was terribly slow... will give www.graphviz.org a try.

It's quick enough if not using such things like gradient background and other processor consuming visualisation.
I made Sunburst with 3 levels and about 100 nodes. Quick enough.

OK, I'm totally biased here (disclaimer: I'm an author of it), but KeyLines can handle several hundred nodes just fine - it is commercially licensed.
In general terms - aside from the issue of what framework to choose - I've found that canvas performance depends strongly on whether the browser+device has hardware acceleration. For example, before iOS5, iPad performance for canvas in Safari really was dreadful, but since iOS5 it flies along. Android is more variable. Most desktop combinations of browser/OS are now fine for high performing canvas rendering.
Another consideration for graph layouts is whether long running layouts block the browser's rendering loop - we've had to develop around the issue of long running (i.e., more than a few seconds) tasks locking up the browser. Users like to see progress bars ticking along & that is possible provided you take the right steps in the layout code..

Related

How to obtain good framerate using javascript?

I'm trying to apply filters to full-hd videos in javascript using pixel manipulation.
I created a demo using hidden canvases, web workers and transferables:
http://lab.jure.it/ww/ww.html
The result is that using web workers the browser's tab crashes in a short time, and the video has very low performances (~5fps).
If you select "Web workers: 0" ww are not used, the performance is better (~15fps) and the tab doesn't crash.
What can i do about it? The goal is to obtain a good framerate (~30fps) avoiding SVG or CSS filters.
Thanks.
Looping through all pixels and converting them on CPU is not a good idea. That's what GPUs are for. In past, that would mean you have to use something nasty, like Flash.
Fortunately, new technologies are emerging and graphic acceleration is available in most popular browsers. It's called WebGL and it allows you to make use of graphic card for these things.
Unless you want to learn all the internal secrets of WebGL (it's quite complicated), I advise you to use PixiJS framework, which is designed for 2D animation.
You can see their filtering demo here: http://www.goodboydigital.com/pixijs/examples/15/indexAll.html
More demos and examples are here: https://pixijs.github.io/examples/#/basics/basic.js

Javascript big-data visualisation

I'm about to develop a UI for medical research application. I need to make a time series line graph. Main issue is the amount of data:
5,000 points per graph, with a few of them displayed simultaneity. I’m expecting 50,000 points processed all together.
The question is what presentation library?
The main features I’m looking for are: Handles huge data sets, Zoom, annotations, live update.
I’m already looking into http://dygraphs.com/ and http://meteorcharts.com/
I wouldn't want any library that renders the data as DOM elements, or that uses SVG (from performance perspective)
Well, I think I'll give everyone my own answer to my question:
Dygraphs (http://dygraphs.com/) seems to be on the spot. The documentation, although a lot of apparent efforts, leaves a lot to be desired. But from performance, features and flexibility, it's the best I've seen. At least for my current project needs.
Way to go, Dygraphs!
Have you checked out D3? I'm using that for a lot of graph visualization. It looks like this example renders to svg.
My stuff renders to a SVG for force graph visualizations too, but it looks like D3 might be able to use either a canvas or SVG, but I'm not positive about what all can be rendered to which. Honestly, I'd give D3 a try even with SVG, it might be fast enough. I remember reading something about someone simulating thousands of particles using D3's force graph visualizations without issues. It's SUPER easy to get your data into the right format for it to use.
Good luck!
I am developing a very similar application.
I am currently using Flot for the chart rendering. It handles annotations and zoom, take a look at their plugin library.
I recommend this downsampling plugin which will speed up graph rendering. Rendering 5000 points on your graph is useless: you have less vertical pixels on your screen than that! so this library will only render those that actually have a visual importance.
This only gives you the graph. You may want some kind of dashboard to present all that... I am currently looking at Grafana, which is used for a totally different purpose but makes awesome dashboards. It may be possible to "rip out" their dashboarding features (it uses Flot as well).
Another option is Hightcharts, but that's not free.
Check raphael js Library
Raphaël is a small JavaScript library that should simplify your work with vector graphics on the web. If you want to create your own specific chart or image crop and rotate widget, for example, you can achieve it simply and easily with this library.

Javascript Optical Flow Implementation

I'm looking for an optical flow implementation to run on my web app in html5 canvas, but didn't found something immediately usable. If I choose to implement it by myself, is it be possible to achieve (near) real-time performance?
Or, since in the current setting, I actually just want to know the main optical flow is moving to the left or right, are there some easier algorithms I can use?
I made this little library which does (I hope) exactly what you are asking for.
A demo
Which utilizes this library to control the ball by moving your hands.
I made a real time feature tracking that can generate sparse optical flow and point trajectories. It uses asm.js, so it runs faster on firefox (50ms per 320x240 frame - 1500 points)
www.ensta-paristech.fr/~garrigues/js_tracking/javascript_video_tracking.html

What is the best approach to producing graphical charts in a browser?

I've started a new open source project aimed at providing a quality project management experience. To do this, I need access to a set of chart tools (Flash is off the table), and very specifically one that includes a Gantt chart. I've done my homework and shopped around the web and I've more or less come to the conclusion that what I want doesn't exist, at least not for free. So chances are I'm going to have to write this from scratch.
If I was going to create a Gantt chart with which people could interact with (which I'm assuming means having excellent DOM support), then what technology would I use? Should I go with SVG? Or HTML5 Canvas? Something else? Your suggestions are much appreciated.
Also, a requirement would be that whatever library I use needs to be actively supported in the community (i.e. no dead projects).
I would not think there would be many free options as this is a niche-need.
JS Option:
http://www.jsgantt.com/
http://code.google.com/p/flot/
Promising Perl modules:
http://cpansearch.perl.org/src/DARNOLD/DBD-Chart-0.82/dbdchart.html
http://search.cpan.org/~awestholm/Project-Gantt-1.03/Gantt.pm
Update:
There's been amazing advancements in terms of interactive/web charts in the past few years. Shortly before your question was asked, D3.js was created, which has become a generally accepted library, which uses SVG to implement visualizations. Here's a basic example and a more advanced implementation using D3. Note; Gantt charting is still in its infancy; D3 will most likely revisit it in the future.
The argument of Canvas vs SVG is one that has been considered many times. You should read this article by Microsoft; How to Choose Between Canvas and SVG for your Site. Basically, if you have many elements you have to display, Canvas will perform much better. If accessibility is a priority, SVG is better.
In terms of working with Canvas vs SVG, canvas feels more fluid and it is certainly more capable with WebGL, but SVG is more transportable. They both have their merits.
If you're going to make your own, I'd recommend the SVG library Raphaël, which allows you to draw things using SVG fairly easily. It's also simple to make mouse event handlers and other things, which you could use to make it interactive.
I haven't had much experience creating interactive graphics with canvas, but my instinct is that it would be hard to handle mouse events since you don't have "elements" to add event listeners to.

Is javascript / HTML5 capable of supporting "flash like" animation and drag and drop

With apple browsers not supporting flash or silverlight, there is a real incentive to avoid flash / silverlight to avoid losing that audience when building a web site. That being said there is certain functionality that it seems like you can only really do in flash / silverlight
for example alot of simple games where you can move things on the screen like this site all seem to be built in flash. also, a lot of drag and drop functionality where you can drag one object onto another like these game sites.
After lots of searching I can't find any that are not either flash or silverlight based.
In particular i am looking for drag and drop support of one element onto another
my question is if you need this type of functionality is javascript / html 5 able to do this type of stuff (so you can support iphone / ipad) or are you out of luck.
is there any resource that highlight examples or suggestions of trying to do this type of interactive functionality and how / if you can do this type of stuff without silverlight / flash. also, if anyone has any good examples of existing site who are doing that today that would be great as well.
This is going to be a long discussion about the ability of html5 to compete with flash.
In my opinion jquery is not any close to performance flash or silverlight animation give.
if the comparison is in terms of drag-and-drop, menu dropdowns, fadeIn.fadeOut - jQuery is competitive.
If i will see the jQuery cartoons with lot of layers and objects moving simultaneously - i will probably agree that jQuery has competitive performance.
the things are compare to see the difference:
magnifying glass over the raster picture
smoke/water/fire emulation
compound 3D objects like fractals with deep branches
when HTML5 will have it - then i will agree that it has competitive performance. All that i see today is picture slideshows and couple of games that work on html5.
You can check Easel.js by Grant Skinner, used in Pirates Love Daisies.
Also, other frameworks are:
enchant
limeJS
akihabara
JQuery UI has that for long time, works in all modern browsers, not just HTML5
JQuery UI Demos
You should checkout canvasdemos.com. It has a lot of good examples of what can be done. You can take a look at the source code behind these - some even help you in that regard. e.g. the pool game
Other good examples include the doom like "game" (you can walk around in 3D dungeons).
The Frog Log game was the winner in the 10KB coding challange
Also this was the first result for a search of html5 animation demo in google. It has links to 48 demos. Some of them are really cool. Unfortunately the code for a lot of these have been minified, but they still might give you a few ideas about what you can achieve.
So it's fine for making simple dressup type games. However, if you are looking to make anything that's CPU intensive, you should look into some performance benchmarks like this. HTML5/Canvas based animation is still quite far behind flash in terms of performance. Getting consistent behaviour across the various browsers will also be an issue.
HTML5 and related technologies (WebSockets, WebGL, web storage, File API, media capture, etc) are quickly moving towards parity with (and in some cases exceeding) what can be done in Flash/Silverlight.
The HTML5 Rocks slides are a reasonable starting point to see what is possible (you need an HTML5 capable browser). In particular, the Canvas example demonstrates image manipulation (drag, rotate, resize) which is the core functionality needed to implement dress-up games.
Flash was designed for animation. The tweens were meant to be used for animating drawings. Because it was marketed to every Tom, Dick and Harry, people started using it to animate hideous menus and flying content text. And Adobe complied to this new use, building an abode of total chaos.
Flash is still the best animation engine for the web, it should never have catered to full flash websites.
Many HTML5 fans out there, but it needs to be said: Canvas is a decade behind Flash. But for everything other than animation, Flash is an abomination.
In old browsers, you can emulate drag'n'drop of elemnts from the DOM but in new browsers, you can also drag'n'drop files (like images) and there are events for it: https://developer.mozilla.org/en/DragDrop/Drag_and_Drop
For flash-like animations, it's been possible with JavaScript for a long time but doing some bug ones was really hard and often slowing down the page.
Now, there is canvas and WebGL that allow you to do it in a more convinient way (for the complex ones).
And with canvas, WebGL, CSS animations (if you use the tric to make the browser think it's 3D), you get CPU accelerated so it's way faster.
There is also requestAnimationFrame that allows to optimise the reflows and therefore the script.
The best example I know on what can be done is the Quake II port to the Web :
Video: http://www.youtube.com/watch?v=XhMN0wlITLk&feature=player_embedded
Project's site: http://code.google.com/p/quake2-gwt-port/
as said in soe of the answers above, I'm pretty sure jquery's draggable/droppable plugin will do the job for you if you just need a basic drag and drop dress me up type of game. Basic premise is this:
in the default example, your avatar to wear the clothes would be a div with a png/gif.jpg background image of a girl/boy whatever(instead of an orange drop here background)
the clothes will be the "drag me to my target" objects in the example. you can create them as divs or even image tags that have the draggable class in them so you can drag them around and drop them in the orange boxes/avatars.
you can save the data using ajax, which is also covered in the examples there(or other tutorials in the net, it's easy)
???
PROFIT
Just try it out and see for yourself. If you need any help you can just ask here again, but I do think that the jquery UI answers are valid answers to your problem.
I don't have an example site to show you, but I'm pretty sure given some images and stuff I can whip out something...if I had the time lol.
You can definitely do these "flash-like" things now in HTML5 web browsers. Check out the examples at http://www.chromeexperiments.com/
In fact HTML5/CSS3/JS can do anything flash can do. But there are some drawback :
It is not yet mature. Lot of bugs, lot of difference in implementation depending of browsers and many people simply don't have yet browsers that support it.
Adobe has a really nice set of tools that help making complex flash applications. This doesn't exist (yet ?) at the same level for HTML5.
On a side note, neither flash, neither HTML5 will really shine on mobiles phone. People prefer native applications anyway. You might need to provide a web version, but you'll need too a app version (one per big phone player).
We can speculate how HTML5 will rule the word in the next few years, but as of now, impact are limited outside of nice looking demo that consume 100% of CPU (really, really bad for mobile device).
For drag and drop support, anybody can do that - in HTML4 and in any browser with a few lines of javascript - inside one page, or can think to do it on between 2 browser windows of the same website. Doing drag & drop between browser and any native desktop application is another thing.
For a great example of what you can do with HTML5 in terms of drag and drop, I suggest you take a look at this article and in particular the short demo at the beginning. The article also highlights a few other goodies that come with HTML5, such as localStorage and the HTML5 Canvas.
For a more detailed tutorial on the HTML5 drag-n-drop API specifically (really it is a Javascript API), take a look at this other article. It is dated from December 2009 but still valid.
Lastly, this video gives you a good insight on some of the cool visual effects that you'll be able to do with HTML5 (SVG, Canvas, CSS3, WebGL, ...). More of a marketing video I'll admit but a good illustration of some of the more powerful HTML5 features (at least from a visual stand point) and of what we'll start seeing in our browsers in a not so distant future...
Disclaimer: I don't work for Mozilla. I just happen to have researched this topic in the past and found that the material produced by Mozilla, and in particular the demos from Paul Rouget, to be the most instructive.
jQuery UI is an amazing library...
Drag: http://jqueryui.com/demos/draggable/#default
Drop: http://jqueryui.com/demos/droppable/
I belive that the droppable examples will answer your question of "In particular i am looking for drag and drop support of one element onto another"

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