I would like to use D3 to build simple charts with literally hundreds of millions of data points.
Obviously, I won't be attempting to plot millions of points at a time. Only a very, very tiny fraction of those points (<1000) would be in view at any given time. I'll download pre-processed data "on-demand" from the server depending on the current view and zoom level, and would like to use D3's built-in zoom and pan behaviors.
Basically, imagine an infinitely wide bar chart that pans back and forth, and alters itself to show the appropriate level of detail depending on the current zoom level (e.g. semantic zoom).
What techniques are available in D3 to achieve this, yet still have it feel responsive and smooth? What should I avoid doing? Are there any examples of this out there?
Examples: Have a look at Fabian Fischer's BankSafe, an award-winning entry to this year's VAST Challenge. Not sure if the code is available, but the report summarising the techniques he used certainly is. The dataset was also in the order of "hundreds of millions" and - if I remember correctly - had a zoom technique similar to the one you describe.
I would highly recommend you look into using canvas over svg. From what I've seen, having thousands of SVG elements doesn't scale particularly well. Microsoft has a pretty good writeup for how to know which to choose: http://msdn.microsoft.com/en-us/library/ie/gg193983(v=vs.85).aspx#Using_Canvas_AndOr_SVG
Related
I made an app that detects objects occupying the smartphone camera and now I want to draw the bounding boxes.
I've seen more than one way to do it and so far I'm planning to use the react-native-canvas library or to create a button in form of a bounding box located in the corresponding coordinates, but I'm wondering what the least resource-intensive solution would be.
This is because object detection already takes up a lot of resources and now I am going to add a function that draws bounding boxes several times per second, so I will surely have to lower the detections per second, but the ideal would be to lower them as little as possible. This is one of those situations where a few fractions of a second will be significant in performance.
I'm pretty new to react native so I need some help finding the optimal solution.
For example plotting buttons without installing an external library and that might work faster, I'm not sure if that makes sense.
Hopefully somebody can point me in the right direction.
Thanks.
I'm writing an astronomy application using Apple's SceneKit and want to provide a skybox of stars to surround a planet.
I have found a large JPEG (8192x4096) with suitable content but my "camera" field of view (10 degrees) magnifies the skybox image background enough to cause serious loss of resolution. In short, it doesn't look good .. here's a screenshot showing blurry stars:
https://ramsaycons.com/screenshots/SkyBoxRes.png
One solution for greater fidelity would be, I imagine, to use a resolution independent 'material' image like a PDF, but SceneKit doesn't support PDF 'materials'.
Or, I could find, or build, a better or bigger image for the skybox material. For example, a (32768x16384) would look better, at the cost of a massive image ~ the 'small' one I'm using now is nearly 8MB already.
Another option would be to move closer to the planet and widen the field of view, but I don't want to move the camera so close (specifically, because I want it 'above' geosynchronous objects in my model).
This code-less question feels not quite appropriate for StackOverflow, but my reading of related Q&A's here reveals a knowledge of clever SceneKit tricks I wouldn't have thought off .. maybe there's a trick for me out there!
I'm working on a form that shows many our company's products in a FlowLayout, but on some categories that hold many products, performance in scrolling is noticeably affected. I switched to a List so I could leverage the performance benefits of using a renderer, but now I'm not happy with the layout since there's a lot of wasted space, especially if the device is in landscape mode.
My next thought was to use a Table, which I believe also uses renderers to optimize the display of its data; but to mimic a FlowLayout, I'd need to get the preferred width of some placeholder component, then divide the container's width by that to get the number of columns, and then fill the model with that number of columns in mind. I'd also need to change all that if the device changes orientation.
Before I go down that rabbit hole, I'm wondering if I'm making things unnecessarily complicated for myself and if there's already something that I can use to achieve that goal. So to summarize, what would be the most efficient way to display data (that would be shown as buttons) sequentially from left to right, and top to bottom?
I wouldn't use FlowLayout for anything serious although I doubt its the reason for your performance issues, those probably relate to something else. There is a performance how do I video which is a bit old but mostly still relevant: http://www.codenameone.com/how-do-i---improve-application-performance-or-track-down-performance-issues.html
In design terms flow layout is hugely problematic since the elements are not aligned properly thus producing a UI that doesn't look good when spanning multiple rows. I suggest using a grid layout which has a mode called auto fit. By using setAutoFit(true) on a grid of even 1x1 all the elements will take up all available space uniformly based on screen size and adapt with orientation changes.
I'm looking at some new options for displaying a percentage value as a fill in a custom shape. Consider the effect to be similar to a "progress thermometer" in a traditional dashboard UI sense.
Considerations
Goal - a graphic element showing a percentage value for a custom report.
Format - Either a full graphic (or infographic) itself, or part of a PDF via Photoshop/InDesign or even iBooks (as an excuse to use it).
Usage - I'd like the process to be programmatic, for re-use. It needs to be accurate, and I'd like the solution to be somewhat object oriented to apply to other datasets and graphical containers. This rules out hand-drawn charting.
Source data - currently a pivot table in Excel, but I can work with any other host as required.
Shape - is a custom vector shape that will originate from Illustrator/Inkscape. final format as best fits resolution and rendering of the report. I would also be interested in any other generative shape ideas (such as java/javascript).
Fill - I'd like to be able to represent the fill as both an actual percentage of total area (true up), and as a percentage of the vertical scale. I'd imagine this flexibility would also help reuse of the method as a fill value against selected object variables (height, area, whatever).
I know I'm being slightly vague in the programming languages or hosts side of things, but this gives me an opportunity to break out of the usual analytic toolchain and scope out some innovative or new solutions. I'm specifically interested in open source solutions, but I'm very keen to review other current methods you might suggest.
This might be a little open ended for you, but d3.js is very powerful. There might be some useful templates on the site, or you can build your own from the library.
If you limit yourself to shapes where the percentage can be easily converted into a new shape by varying one of the dimensions, then the display part can be covered by creating a second shape based on the first one, and filling in 100% of the second shape.
This obviously works best with simple shapes like squares, rectangles, circles, etc, where it is simple to convert "50% of the area" or "75% of the height" into manipulation of vector nodes.
However, things gets significantly more difficult if you want to support genuinely arbitrary custom shapes. One way to handle that would be to break up a complex "progress bar" into "progress pieces" (e.g. a thermometer bulb that represents 10% of total progress, then a simple bar for the remaining 90%).
As has been mentioned, D3 seems like it would meet your needs - here are some simple examples of what I think you are asking:
Changing the fill color of a distinct shape: http://jsfiddle.net/jsl6906/YCMb8/
Changing the 'fill amount' of a simple shape: http://jsfiddle.net/jsl6906/YCMb8/1/
I'm trying to write an CAD-like application in WPF(.NET 4.0) that needs to be able to display a lot of 2D points/lines. It will be used to display CAD-plans of entire cities with zoom, pan, rotate and point snapping on mouseover.
Right now I purely use WPF. I read the objects from the CAD file draw them into a StreamGeometry, use it as stroke of a new Path and add it to a Canvas, with several transforms.
My problem is that this solution doesn't scale well enough. It works fine with small CAD-files, but when I want to display like half a city(with houses and land boundaries) it is very very delayed.
I also tried to convert my CAD-file to an image, but
- a resolution a 32000x32000 is sometimes not enough
- when zooming out the lines are too thin.
In the end I need to be able to place this on a Canvas(2D/3D) as background.
What are my best options here?
Thanks,
Niklas
wpf is not good for a large 3d models. im afraid it is too slow. Your best bet is direct 3d or openGL
However, even with the speed of direct3d,openGL you will still need to work out how to cull as many polygons/vertices as possible before the rendering of the scene if you are trying to show an entire city.
there is a large amount of information on this (generally under game development)
there are a few techniques including frustrum culling, near and far plane culling.
also, since you probably have a static scene you may be able to use binary spacial partitioning.
As I understand the subject is 2D CAD system within WPF.
Great! I use it...
OpenGL and DirectX are in infinite loop OnDraw always. The CPU works all the time.
WPF/Silverlight 2D is smart model.
Yes, total amount of elements (for example, primitives inherited from Shape) must be not so much. But how many?
I tested own app (Silverlight). WPF will be a bit faster I hope...
Here my 2D CAD results. Performance is still great. Each beam consists of multiple primitives.
Use a VirtualCanvas like this one from Chris Lovett.