I'm looking into writing a program that will show a graph to the user. The graph will change over time (the user should be able to right-click on a graph item and ask for more detail, which will pop out new bits of the graph), and the user might be able to drag parts of the graph around. I would ideally also like to be able to specify the relative layout of certain parts of the graph myself while leaving the overall layout up to a library, but that's not essential.
I'm trying to decide on a graph layout library to use. As far as I can tell, the two leading candidates are Graphviz and Dynagraph. The Dynagraph website suggests that Graphviz is for drawing static graphs, and that Dynagraph was forked from Graphviz and contains algorithms for graphs that will be updated. It has a sample program called Dynasty that does exactly what I want. However, the Graphviz site contains an example program called Lefty which seems to do exactly what I want. Graphviz also seems to be much more widely used, judging by Google (and SO) results.
Finally, I'd like to code the GUI part in a language like Python or Scheme, which makes me a bit hesitant to use C++ because I understand it's harder to interface that to interpreters.
So my question is, which library is better for what I'm trying to do? Do they both have strong and weak points? Has one of them actually ceased development and is just leaving its website up to confuse me?
(I've seen Simple Dynamic Graph Display for C++ and Open source libraries to design directed graphs, but I can't tell whether they're right about the Graphviz or Dynagraph choice because of Lefty and also the language issue.)
Try Open Graph Drawing Framework. This is the best one I have seen.
Related
I would like to be able to use a tool that lets you visualize a program's control flow(s) in the context of its source code. To clarify, such a tool should basically show what happens in a program by spitting out a human-readable abstract syntax tree in the form of a multidigraph with nodes containing snippets of source-code translation units. The resulting graph initial node would, I presume, contain the block of code starting with a program's entry point (that'd be main for a C or C++ program.) New nodes would be created when a node needs to reference another block of code, whether that might be in the current file or in another one, and arrows would connect the nodes. Does such a tool exist, or would it have to be created from scratch?
You aren't going to get a tool that does this for arbitrary languages off the shelf. There are too many languages, each with its own syntax and semantics. You somehow need a tool per language. You might find such tools for very commonly used languages, e.g, Understand for Software.
I think that the only way to do this is to build metatools that enable the construction of language-specific tools relatively easily. Such a tool has to have the common machinery needed by all such language processing tools: strong parsers (so writing grammars for languages is relatively straightforward), AST construction machinery, symbol table support, routines to build control and data flow graphs. By providing such machinery, one can build language front ends for modest costs.
There's a class of tools that does this, program transformation. Most of them have parsing engines, but not the rest of the mechanisms I have suggested above.
I believe this enough to have invested 20 years of my life to building
such meta tools. Our DMS Software Reengineering toolkit shows its strength in being able to parse some 50+ languages, including the stunningly hard C++14 (both MS and GNU variants). It shows symbol table support and control flow graph construction for COBOL, Java, C, C++. (We can't do everything at once; pedaling as fast as practical).
[DMS builds these graphs as data structures rather than "showing" them; the examples on that page are drawn with the additional help of DOT].
One of the few other tools that tries to do this is Clang/LLVM; this covers a wide variety of popular languages. Clang doesn't have any specific support for parsing that I know about; you get to code it all yourself. I think you get control flow graphs only after you convert the language to LLVM. I don't think it has any specific support for drawing control flow graphs, either.
An older tool with a good reputation for multi-language support in this space is CoCo/R;
I don't know a lot about it. I know it parses,
and has some support for ASTs; I don't know what it does
about control flow analysis.
I am working on a technical engineering solution of connecting systems to other systems throughout a building environment. I am attempting to create a diagram that visually shows an input energy and then flow it through a series of systems, each of which will use a portion of that energy for operation. The diagram will update with different operations based on amount of energy, time of day, location, and desired output (heating or cooling).
The problem I have is that I need an extremely visual way of laying this out in a dynamic way. This all sounds super technical but to simplify, I'm basically creating a systems operation diagram (OR workflow diagram) that needs some serious power and visualization. I hope to make this a powerful tool in which, environmental data will automatically alter the diagram's configuration.
I am comfortable with learning a programming language if necessary but I'm just not sure which will be the best. I would like to start simple with one configuration and keep implementing new parameters. I was looking at Python, JavaScript, C++, C#, and VisualBasic. I almost imagine this like a game design for aesthetics but I'm not sure.
Below is a static example of the systems diagrams created for one specific case. This example is only the diagram and lacks any interactivity. Basically I would like to make a dynamic and interactive diagram that can take inputs and alter itself. But for starters, change visually with specific button presses.
Original
I'm looking for ways to programmatically convert my GPS logs to images and would like to do this in Ruby... if that's an acceptable tool. I have no GIS background whatsoever but as a programmer i think it's an interesting problem to look at.
Here is what I have come up with so far. First you'll need some kind of graphing library. I went for gnuplot as I found a Ruby binding for that one but R seems hot these days. I created a small script that converts a GPX file and feeds the data to gnuplot resulting in something like this: alt text http://dl.dropbox.com/u/45672/gpslog.png
This looks fine but gnuplot seems really a tool to create graphs, not spatial data. Is this the way to do it or are there much better solutions available?
Here is another example, any idea how you build stuff like this?
Answer to First Question
Since you stated that you "would like to do this in Ruby...if that's an acceptable tool", I'll go out on a limb and assume that you might be open to a non-Ruby solution if it meets all of your other requirements.
I would recommend Python primarily because in the first chapter of Beginning Python Visualization, Shai Vaingast—the author—goes through an example of reading in GPS data from a GPS receiver and then plots the results. If you're open to a Python-based solution, this book would be a great resource.
Here are the Python packages that are used to read and plot the GPS data:
pySerial to read the GPS data in from the serial port
matplotlib to plot the data. "matplotlib is a library for making 2D plots of arrays in Python. Although it has its origins in emulating the MATLAB® graphics commands, it is independent of MATLAB, and can be used in a Pythonic, object oriented way."
Here's an example figure created by Shai Vaingast showing off a few of the different capabilities of matplotlib for plotting GPS data.
If you are not open to a Python solution, and would prefer Ruby—for whatever reason—I understand. I tried to search for an equivalent of matplotlib in Ruby, but I didn't find an equivalent package.
Answer to Last Question
Here is another example, any idea how you build stuff like this?
Looking at the lower, right-hand corner, it appears that DISLIN was used to create that image. While DISLIN is available for quite a few programming languages, the DISLIN software requirements page does not show that Ruby is supported.
According to the DISLIN website,
DISLIN is a high-level plotting library for displaying data as curves, polar plots, bar graphs, pie charts, 3D-color plots, surfaces, contours and maps.
The software is available for several C, Fortran 77 and Fortran 90/95 compilers on the operating systems UNIX, Linux, FreeBSD, OpenVMS, Windows, Mac OSX and MS-DOS. DISLIN programs are very system-independent, they can be ported from one operating system to another without any changes.
For some operating systems, the programming languages Perl, Python, Java and the C/C++ interpreter Ch are also supported by DISLIN. The DISLIN interpreter DISGCL is availble for all supported operating systems. See a complete list of the supported operating systems and compilers.
Do you really want images, or just a way to visualize the data? How about using the google maps api?
Check out this link:
http://google-dox.net/O.Reilly-Google.Maps.Hacks/0596101619/googlemapshks-CHP-4-SECT-10.html
I think that using gnuplot from any programming language is a good starting approach.
However, I strongly suggest adding the set size ratio -1 gnuplot command somewhere in your code, as this will make the x and y axis scales equal in the plot, which is extremely important.
You could also augment the line with very small point markers equally spaced in time (assuming you have time information in your data, or at least you know that rows are sampled at regular time intervals), so you get a feel of the speed of the movement, which is otherwise lost (i.e., large-spaced point markers on the line mean faster movement). Obviously you should pick a time interval between point markers that makes them appropriately spaced, or compute such time interval automatically: i.e. by computing the length of your curve, converting it in pixel units, and dividing by anything between 10 and 100, to get the total number of points you want to place. The time interval is then given by the total time of the track divided by such number of points. This should work robustly for reasonably regular movements.
Another option is to use a different charting system than gnuplot, which is powerful but a bit old. Options known to me include:
gruff, which is for ruby but seems to miss 2D plotting abilities (which is an obvious requirement).
XML/SWF Charts, which is powerful and flexible, but commercial. In this case, you would use ruby or any other programming language to generate an XML file which then gets interpreted to an interactive graph.
Google Chart API, which can return chart images over the web, forging an appropriate GET or POST request in your code. In this case, you are intersted in the lxy chart type, possibly compounded with a scatter chart for the point markers.
The third option seems the most fun.
GDAL is very popular Open Source GIS kit, there are GDAL Ruby bindings. If you want map data, open street map is very useful. Combined plotting of OSM and the GPS will give pretty nice results. GDAL/OGR Api tutorial is here.
If you want to look more into R, there are Ruby bindings for that too, but there has been no activity on the project for over a year:
http://github.com/alexgutteridge/rsruby
Maybe you have heard of Processing already but have you heard of Ruby-Processing ?
From the Ruby-Processing readme:
Ruby-Processing is a Ruby wrapper for the Processing code art framework.
…
If some quality time with Ruby is your
idea of a pleasant afternoon, or you
harbor ambitions of entering the
fast-paced and not altogether
cutthroat world of Code Art, then
Ruby-Processing is probably something
you should try on for size.
…
Processing is an MIT-developed
framework for making little code
artifacts, animations,
visualizations, and the like,
developed originally by Ben Fry and
Casey Reas, supported by a small army
of open-source contributors.
Processing has become a sort of
standard for visually-oriented
programming, strongly influencing
the designs of Nodebox, Shoes,
Arduino, and other kindred projects
For my job i've been using a Java version of ARToolkit (NyARTookit). So far it proven good enough for our needs, but my boss is starting to want the framework ported in other platforms such as web (Flash, etc) and mobiles. While i suppose i could use other ports, i'm increasingly annoyed by not knowing how the kit works and beyond that, from some limitations. Later i'll also need to extend the kit's abilities to add stuff like interaction (virtual buttons on cards, etc), which as far as i've seen in NyARToolkit aren't supported.
So basically, i need to replace ARToolkit with a custom mark detector (and in case of NyARToolkit, try to get rid of JMF and use a better solution via JNI). However i don't know how these detectors work. I know about 3D graphics and i've built a nice framework around it, but i need to know how to build the underlying tech :-).
Does anyone know any sources about how to implement a marker-based augmented reality application from scratch? When searching in google i only find "applications" of AR, not the underlying algorithms :-/.
'From scratch' is a relative term. Truly doing it from scratch, without using any pre-existing vision code, would be very painful and you wouldn't do a better job of it than the entire computer vision community.
However, if you want to do AR with existing vision code, this is more reasonable. The essential sub-tasks are:
Find the markers in your image or video.
Make sure they are the ones you want.
Figure out how they are oriented relative to the camera.
The first task is keypoint localization. Techniques for this include SIFT keypoint detection, the Harris corner detector, and others. Some of these have open source implementations - i think OpenCV has the Harris corner detector in the function GoodFeaturesToTrack.
The second task is making region descriptors. Techniques for this include SIFT descriptors, HOG descriptors, and many many others. There should be an open-source implementation of one of these somewhere.
The third task is also done by keypoint localizers. Ideally you want an affine transformation, since this will tell you how the marker is sitting in 3-space. The Harris affine detector should work for this. For more details go here: http://en.wikipedia.org/wiki/Harris_affine_region_detector
I am trying to code a flowchart generator for a language using Ruby.
I wanted to know if there were any libraries that I could use to draw various shapes for the various flowchart elements and write out text to those shapes.
I would really prefer not having to write code for drawing basic shapes, if I can help it.
Can someone could point me to some reference documentation with examples of using that library?
Write up your flowchart as a directed or undirected graph in Graphviz. Graphviz has a language, dot that makes it easy to generate graphs. Just generate the dot file, run it through Graphiviz, and you get your image.
graph {
A -- B -- C;
B -- D;
C -- D [constraint=false];
}
renders as
digraph {
A [label="start"];
B [label="eat"];
C [label="drink"];
D [label="be merry"];
A -> B -> C;
C -> D [constraint=false];
B -> D [ arrowhead=none, arrowtail=normal]; // reverse this edge
}
renders as
You can control node shapes and much more in Graphviz.
It sounds like you're going to be limited mainly by the capabilities of whatever user agent you're building for; if this is a web project, drawing capabilities are going to be dependent on the browser. Since Ruby is running server-side, you would at minimum need some JavaScript to allow dragging/zooming, etc. There's plenty of examples of JavaScript being used for vector drawing (just google "javascript graphics library"), but all require coding, and I haven't seen any library that abstracts this elegantly.
ImageMagick has a Ruby binding called RMagick (sometimes known by other names, depending on the repository). (Link)
I haven't used it myself, but I believe it will do what you're looking for. You will need to do some coding, but it's along the lines of
draw.rectangle(x1, y1, x2, y2)
draw.polygon(x1, y1,...,xN, yN)
The simple answer is that (at time of writing) what you want almost certainly didn't exist. Sorry!
If you're Windows-based then I'd look for a product in the .NET space, where I expect you'd find something. You're probably going to have to pay real money though. I suppose, if you're brave, you may be able to talk to it using IronRuby.
From a non-MS environment I would be hoping for a Java-based solution. As already mentioned, within the Web world, you're going to be hoping some something JavaScript-based, or probably more likely, something from the Flash (or maybe even Silverlight?) world.
Actually, if you want to stay in Ruby and don't mind some risk, Silverlight might be a way to go - assuming the DLR stuff actually works (no experience here). Ruby - much as I love it - hardly has the most mature GUI structure around it.
Update: Since writing this (approaching 5 years ago) the situation has improved - a little. While I'm still not aware of any specific Ruby graph-drawing libraries, there is improved support for Graphviz here (Github) or by gem install ruby-graphviz. I've found that for simple graphs, it's quite possible to write the script directly from Ruby.
I am totally sure, but check out cairo bindings for ruby. Pango for text. I am investigating then currently and came across this page.