Is there any Java image processing library that is as easy to use as and provides the set of functionalities provided by RMagick? (I have seen JMagick and unfortunately that is not the kind of library I am looking for.)
EDIT: Please note that the speed does not concern us as such. What we are looking for is an easy-to-use library that provides many common operations built-in.
Check out this, especially JAI. i dont have experience with this libs, but its on my todo list. there are demos somewhere on the site. maybe it is what you are looking for?!
There's ImageJ, which boasts to be the
world's fastest pure Java image processing program
It can be used as a library in another application. It's architecture is not brilliant, but it does basic image processing tasks.
It's not a pure Java solution, but the IM4JAVA project works for many uses. Im4Java itself is a pure Java library that uses the commandline version of ImageMagick as its back-end. It's easy to use and exposes pretty much all the functionality of ImageMagick without the dangers of including native code in your app. That means you can safely use it in application servers etc. without worrying that a crash in the native code will bring down your whole server.
Related
I have a Java application that runs on BlackBerry (JDE 4.5). I want to port this application to Android, and be able to maintain the 2 applications simultaneously. I may also want to port this application to other Java platforms (J2ME ?).
I understand that a good part of the code will have to be specific to each platform (UI and other stuff). But I also feel that a lot of the code could (should) be shared (domain related classes).
What is the best way to achieve this, and what are the pitfalls to avoid?
I have been able so far to create a JAR with all my shared classes, that I have been able to integrate into my BlackBerry application (using preverify and rapc). But:
The JAR is a J2SE library. How can I make sure that it will run (or even compile) on BlackBerry, Android or J2ME?
I am also using a JSON library targeting J2ME (https://github.com/upictec/org.json.me/). This library seems to make use of some kind of preprocessing directives (CLDC, see https://github.com/upictec/org.json.me/blob/master/src/main/java/org/json/me/JSONObject.java#L392). How can I use (or convert) this library using the right preprocessing definitions?
This is likely to be difficult:
As you have already identified, the UI code will have to be different for each platform.
There are major differences between Java SE / Android and Java ME-based platforms. For example, ME doesn't have the Collections framework, or the java.io or java.nio stacks.
It is hard to predict from the information you've provided, but there's a fair chance that you'll spend more time fighting the platform dependencies than you are saving by sharing the code-base.
These days, the biggest stumbling block to sharing code this way is that the BlackBerry VM and Android VM both support different versions of the Java language. BlackBerry uses a subset of Java 1.3, Android uses a subset of Java 1.5. (As an aside, neither platform implements a Java VM, both use their own VMs. Java is used as the programming language. Java bytecodes must be transformed to the appropriate native VM format before they can run on the platform.)
The biggest difference you will find as a library implementor is that the BlackBerry lacks the things that were introduced in 1.5, very important things like generics and enums. Even worse, the Collections classes are missing from the BlackBerry. It is unfortunate, but that is the way it has been for a long time now.
This means that to be truly portable you have to write to the lowest-common denominator, which means using (very) old-style classes like Hashtable and Vector, not having generics, rolling your own enums (as in the 1st edition of Effective Java) and so on.
Or you build two libraries, a modern version for Android and a stripped-down version (with just the bare stuff you need) for the BlackBerry.
Hard to say what`s right for you.
Rather than prepackage your shared library, I would consider sharing the library project and having it as a dependency in your mobile applications' build process. That would allow you to share the code base, but have it built by the appropriate builders for your target devices. With a bit of IDE magic and some attention to detail, you should be able to pick up errors before anything is shipped out.
Alternatively, set up your library project to use two separate builders to pick up errors. That would allow cleaner distribution, but you may run into problems trying to convince your IDE to treat the project as being device specific in order to identify problem areas.
It would be likely that you would end up supporting the lowest common denominator device (cough Blackberry), and forgoing the additional facilities of the more extensive Java implementation on Android.
Unfortunately the answer will be one of experimentation. Try it and see what happens.
The article Porting Android code to BlackBerry has some good detail on how to work with code shared between the two platforms.
it will be very difficult to create shared library for blackberry and android.
if you want simple method, create your application as web app.
using
phonegap with jQtouch
I just ordered an Android smartphone and want to start playing around with creating my own applications. Now the question is which language to use, the native Java or Python using SL4A (former ASE).
I tend to Python, as I know it much better than Java, but I'm wondering what I would be missing using a "second class" language on Android. On the SL4A website it is also stated to be alpha quality software, which is not exactly encouraging.
I'm also not quite sure what the limitations of the scripting environment are and if they would be problematic.
At the moment you cannot create a releasable program with Python (or any other scripting language) using SL4A. I have heard rumours that this is something Google is working on, but even if they do enable it Python apps are likely to be slow and power-hungry compared to Java. Also the scripting API only gives you access to a limited subset of the native Java API. I would not consider using SL4A for serious development work at the moment, only for one-off scripts and prototyping.
Take a look at Scala. It is a statically typed language on the JVM, but uses type inference to remove most of the noise that you get in Java. It also fully supports functional programming, and has a lot of pythonish features. Because it is statically typed it is as efficient as straight Java with none of the disadvantages. IMHO it is the language that Java should have been in the first place.
A lot of people are blogging about using Scala on Android, so Google around for more information.
More likely will depend what type of applications you will develop.
I would start with Java to become familiar with Android SDK. Anyway first you need to look into some examples, tutorials. Most of them are done in Java, and only a few, probably on the dev site of SL4A for that.
Also there is native development Android NDK, that can be programmed with C++.
But anyway Java rules for general applications.
Adding an update to Dave Kirby's answer:
Issue 55, Distribute scripts as APKs, in the issue tracker at SL4A deals specifically with that.
There is a solution being worked out (may be complete by now) described at SharingScripts. The only issue seems to be that you need to have a interpreter APK already installed.
you may want to check out Ruboto it is a framework for developing Android apps based on JRuby which means your JRuby code can call Android APIs and can also be called back from the Android Java side.
Here is an introduction article .
Consider ising Kivy, if you want to write Android apps with Python. The process of packing script to .apk file is described here.
The problem is, resulting .apk will be big (~7Mb for 300Kb data). It is obvious, because you need to pack there Python runtime and all libraries.
Another solution I have heard of, is Pygame for Android, but it works on lower lewel, so you need to draw graphics manually.
Unfortunately, I have not tried any of this ways yet, but it looks, that I'm going to start using kivy soon.
Is there an easy way to use DirectX in Java? In particular, DirectX's video APIs.
I know that C# might be a more natural choice, but I have my devious reasons for wanting to do something so perverse.
I don't know about easy, but you could always use JNI to load the DirectX libs and invoke the methods.
Using something like Swig you could auto-generate a lot of the code.
Not sure how workable something like that would be though.
There seems to be a standard API about dealing with 3D inside Java.
It probably uses some kind of accelerating technology, may be even DirectX.
But I'm not sure about direct video support in this framework.
I create a library using BridJ (https://bridj.googlecode.com) that wrap DirectX classes, so you can use almost the same code than C++ examples.
You can find the library in https://bitbucket.org/fourthskyinteractive/directx-for-java.
Please, let me know about projects you develop.
There is a set of Direct3D bindings for Java available at http://java-direct3d.sourceforge.net/ but it seems that developement stopped in 2006 with DirectX 9.
Otherwise, there are OpenGL binding for java called JOGL.
The package that you want to investigate is the Java Media Framework (JMF). The core of it is pure Java, and per-platform "performance packs" provide acceleration via native libraries. It currently supports A/V capture and playback in a wide variety of data types as well as streaming via RTP and RTSP.
Sun's JMF home page
JMF SW/HW requirements
Minecraft is coded in Java with LWJGL, but Messiah Andrew's Renderer Wrapper converts the OpenGL to DirectX by using a modified version of the LWJGL libraries. Using these libraries, you should be able to code in LWJGL and have the game be running DirectX.
It seems that most are forgetting that JavaFX and Java3D support both DirectX and OpenGL using the best context for the machine you are on... well actually if you are on windows it attempts to load DirectX if it is newer than your OpenGL version.
I am not telling anyone to use either Java3D or JavaFX, but if you look at the source you can see how it is done.
GrepCode "good for looking for how things are implemented"
Open JavaFX "Open JavaFX project home" source
I should note that you want to look at the com.sun.prism package.
Java3D "Java3D project home" sources
I have been LEARNING development, LOL, for 20 years. Professionally for about 8 possible has never been the question, but how long, and/or is it worth it... Those are the questions.
Good luck my friend!
If you need any help I would be interested in creating a DirectX wrapper for java so
GIVE ME A SHOUT!
I am in the concept phase of an application that is going to have a lot of Audio/Video input and output. I want to do it in Java; but somehow am not fully convinced yet. What do you think? How bad could it be? And any advices?
Why I am thinking Java:
It's the language I'm most comfortable with.
Easier cross platform migration would be a bonus.
Cannot afford commercial platforms (like .NET) or not good enough in other free alternatives (like Python)
I'm also slightly inclined towards C++/Qt; but that would take more time for me as I'm not great in that and I am a bit worried about maintainability.
If you're interested, check out Xuggler. It exposes all the power of FFmpeg, but as a Java API that runs on Windows, Mac and Linux. The advantage is you get all the power of FFmpeg but from Java. The disadvantage is it requires the FFmpeg native DLLs/shared-libraries to be installed.
Easier cross platform migration would be a bonus.
Audio and video means you will be dealing with dedicated native libraries and JNI-wrappers for each supported platform; in this case, the cross-platform argument for Java does not really apply.
I believe that when you want to write an audio/video application, the programming language you will use is the second most important thing. The most important thing is the audio/video framework your application will use since this is what defines your capabilities.
I am aware of two popular generic video frameworks that can be used to accesd most multimedia types: Directshow and ffmpeg. Directshow is tied with windows, so only ffmpeg is left.
Ffmpeg has versions in both windows and unix and, although it is written in C, it can be used from a lot of languages.
There is even a number of java wrappers for ffmpeg (for instance, take a look at xuggle)!
C++ would be the first choice because of performance concerns often present in Audio/Video processing as well as the range of available libraries for video/audio.
You do make a good point about being familiar with Java. If you are pressed for time, this is even more important. However if you can spare some time for learning, C++ would be well worth it.
Regarding .NET: The .NET SDK with everything you need is freely downloadable. Get hold of a free IDE such as SharpDevelop and you are up and running. It's Visual Studio that costs money, you don't need Visual Studio to do .NET development.
Rusty.in,
How about trying to do JavaFX Media API. Recently, the version of the JavaFX is 1.2.0 with GUI Application as well. It supports the Swing. The grammar is based on the script style; however, you can deploy the existing Swing components into the JavaFX.
I hope it helps.
Tiger
Rusty, what did you wind up doing? I too have a video app I'd like to do, but really would prefer Java/JavaFX over C++. The thing about the using Flash and/or the current JavaFX video support is that Flash video playback is not frame-accurate. I really need to be able to stop/start/step on individual frames like you can with QuickTime.
Has anyone tried doing playback with Xuggler and Java/JavaFX?
I'm working on some Flex spike in my company. We are basically evaluating different scenarios etc. What solution would you recommend for embedding Flex components into Java app? Flex <-> Java communication is not (yet...) an issue, just embedding swf into JFrame.
I've done it with EasyJCom. It's pretty straight forward as long as you're using one of the standard Java windowing libraries (Swing, awt). You can see an example (From the EZJCom site) here: http://www.ezjcom.com/FlashTest.java.txt
The people responsible for EasyJCom are also very responsive, and even though we ended up not using their product (Switching platforms), I'd recommend them.
I haven't used JFlashPlayer, but did take a look at the docs, it seems to be adequate as well. I think their license requires you to obfuscate your code. I thought it was a little odd, but maybe I mis-understood the license.
It gets quite a bit more complicated if you don't want to use Com, or if you need to embed in another type of window.
If you need to embed flash cross platform, you may be stuck rolling your own Jini library for the Mozilla plugin. At that point... Maybe it's worth just switching platforms if you aren't too far in. ;)
Haven't tested this, but it looks like JFlashPlayer will do the job. http://www.jpackages.com/jflashplayer/
None of these supports Linux or MacOS. So much for the cross-platform Java and Flash.
I think the best way to do something like this would be to embed something like xulrunner into your java app then have the java app interact with flash via the xulrunner interfaces.