Merge and split tiff images using RPG programming language - tiff

Has anyone ever split or merged tiff image files using the “RPG” programming language ? I know it can be done using Java and libTiff but I need RPG to do it as this is a pure RPG shop. I would appreciate any code showing this implementation.

The best way to do this without writing Java, barring that you actually find an RPG library to do this, is to get an open source library to do it. Whether that library is C or Java, then you just need to write the RPG prototypes to make the RPG calls into C or Java. But you don't have to maintain any C or Java code. Of course, the C might have to be ported, and someone will have to know enough about C or Java to write the prototypes. The porting of C might present a challenge, but writing the prototypes will be easy enough.
I found this: http://www.libtiff.org/build.html
should be able to be built into PASE, then you will have C routines that you can build into a service program and call from RPGLE.

Related

Easiest way to start with VST development

What are the easiest ways to code a VST plugin?
I'm a sophomore in IT education, and I may need to write a VST as an assigment project for Digital Signal Processing course. This means I will probably have to implement an actual DSP algorithm, so if I'm not wrong, that outrules all graphical modular VST maker software.
I currently have C++ (CodeBlocks + MinGW), Java (Eclipse), Python and Octave at my hand. I can also get Visual Studio, Matlab, or some free language/environment for the task. I have also found Faust which is a functional language and I may learn that for this project, because I enjoy learning new languages.
SynthEdit is probably the easiest way to create a working VST plugin while getting the chance to write low-level DSP code. SynthEdit can be extended with custom C++ modules. You could write a module containing your custom DSP code to satisfy your course requirements while using SynthEdit for the GUI and the other VST 'glue' type code. Writing DSP code is only one small part of building a VST plugin from scratch.
If you must write a VST plugin and can't use SynthEdit or similar environments I think the next easiest way would be C++ and JUCE. I don't use either but AFAIK most plugins are written in C++ and JUCE is often praised.
Other VST framework options exist such as VST.NET or Delphi ASIO and VST Library but these are less widely used and you'll likely be more on your own if you run into problems.
I think there are VST modular synths that allow you to custom program the DSP logic, SynthEdit comes to mind but there are more. Search for 'vst modular synth'.
If you like to venture into the .NET world, VST.NET is excellent for beginners. It has a framework that structures and simplifies the VST plugin standard and comes with samples that demonstrate the common plugin scenarios.

Why compilers don't translate in simpler languages?

Usually compilers translate from the language they support to assembly. Or at most to an assembly-like language (bytecode), like GIMPLE/GENERIC for GCC or Python/Java/.NET bytecode.
Wouldn't it be simpler for a compiler translate to a simpler language, which already implement a big subset of their grammar?
For example an Objective-C compiler, which is 100% compatible with C, could add the semantics only for the syntax it extends to C's, translating it into C. I can see many advantages of doing this; one could use this Objective-C compiler to translate its code into C in order to compile the generated C code with a different compiler that doesn't support C++ (but that optimizes more, or that compiles quicker, or able to compile for more architectures). Or one would be able to use the generated C code in a project where only C is allowed.
I guess/hope that if things were working like this, it would have been a lot easier to write extensions for current languages (eg: adding to C++ keywords to ease the implementation of common patterns, or, still in C++, removing the declare before use rule by moving inline member functions to the end of header files)
What kind of penalties would there be? Generated code would be very difficult to be understood by humans? Compilers wouldn't be able to optimize as much as they can now? What else?
This is actually used by a lot of languages, through the use of Intermediate languages. The biggest example for this would be Pascal, which had the Pascal-P system: Pascal was compiled into a hypothetical assembly language. To port pascal would only mean making a compiler for this assembly language: a task a lot simpler than porting the entire pascal compiler. After writing this compiler, you'd only need to compile the (machine-independent) pascal compiler that was written in this.
Bootstrapping is also used quite often in programming language design. Many languages have their compilers written in the same language(Haskell comes to mind here). By doing this, writing a new functionality for the language simply means translating that idea into the current language, putting it into the compiler, then recompiling.
I don't think the problem with this method is really the readability of generated code(I don't sift through assembly byte-code generated through compilers, personally), but one of optimization. Many ideas in higher-level programming languages( weak-typing comes to mind) are hard to automatically translate into lower-level system languages such as C. There's a reason why GCC tends to do its optimization before code generation.
But for the most part, compilers do translate into simpler languages except for maybe the most basic of system languages.
Incidentally, as a counterexample, Tcl is one language that is known to be very-very hard (if not totally impossible) to translate to C. Over the last 20 years there have been a couple of projects that tried this, even one promise of a commercial product but none have materialized.
In part it is because Tcl is a very dynamic language (as any language with an eval function is). In part it is because the only way to know if something is code or data is to run the program.
Since Objective-C is a strict superset of C and C++ contains a very large amount that is a lot like C, to parse either you effectively already need to be able to parse C. In which case, outputting to machine code and outputting to more C code aren't substantially different in processing cost, the main cost to the user being that compiling now takes as long as it originally did plus the amount of time a second compiler takes.
Any attempt to copy and paste the stuff that looks like C and translate the rest around it would be prone to problems. Firstly, C++ isn't a strict superset of C so things that look like C don't necessarily compile exactly the same anyway (especially versus C99). And even if they did, supposing a user made an error in their C stuff, compilers don't tend to provide error information in a machine readable format, so it'd be really hard for the Objective-C to C layer to give the user a meaningful error after receiving e.g. "error at line 99".
That said, many compiler suites, like GCC and even more so like the upcoming Clang + LLVM, use an intermediate form to decouple the bit that knows about the specifics of one architecture from the bit that knows the specifics of a particular language. However, it tends to be more of a data structure than something intentionally easy to express as a written language.
So: compilers don't work like this for purely practical reasons.
Haskell is actually compiled this way: the GHC compiler first translates the source code to an intermediary functional language (which is less rich than Haskell self), performs optimizations and then lowers the whole thing to C code which is then compiled by GCC. This solutions has problems tough, and projects were started to replace this backend.
http://blog.llvm.org/2010/05/glasgow-haskell-compiler-and-llvm.html
There is a compilers construction stack which is fully based on this idea. Any new language is implemented as a trivial translation into a lower level language or a combination of languages which are already defined within this stack.
http://www.meta-alternative.net/mbase.html
However, in order to be able to do so, you'd need at least some metaprogramming capabilities in every little language you add to a hierarchy. This requirement adds some severe limitations on languages semantics.

How do they write different language wrappers for same library?

Generally a library will be released in a single language (for example C). If the library tuns out to be useful then many language wrappers for that library will be written. How exactly do they do it?
Kindly someone throw little light on this topic. If it is too language dependent pick language of your choice and explain it.
There are a few options that come to mind:
Port the original C library to the language/platform of your choice
Compile the C library into something (like a DLL) that can be invoked from other components
Put the library on the web, expose an API over HTTP and wrap that on the client
If I wanted to wrap a C library with a managed (.NET) layer, I'd compile the library into a DLL, exposing the APIs I wanted. Then, I'd use P/Invoke to call those APIs from my C# code.

worth to learn groovy? [closed]

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the question im asking, is it worth to learn a new language like groovy? cause if i learn groovy, it feels like i code in groovy and not java. and how smart is that when i have to be good in java to code desktop applications too in the future. so if i use groovy a lot for web applications, i will just be worse and have to start over to be good in java when i code desktop applications right?
so why don´t I just stick with java and be good at ONE language instead of having to switch between 2 languages and their syntax. Cause it would be so confusing...
Groovy is a nice, scriptable and easier-to-use Java "knockoff" – and I don't mean that derogatively. while Java is a language to be compiled, deployed and (often) run on Enterprise servers where performance matters, Groovy is a language where you can quickly create a program to get something done. Often that something is fairly simple, so it's an hour's or a day's coding effort. Often the code is only run once and then thrown away. Because Java has more boilerplate and formalism in it, you can do this kind of program more quickly and hence more efficiently in Groovy.
However, just to give you some perspective, Groovy is a relative newcomer stomping on the turf of various other, better established scripting languages:
Perl is one of the grandfathers of scripting languages; rarely does a Unix server get installed without Perl on it, and Perl scripts are the lifeblood of many servers. However, Perl is a write-only language that looks like line noise to the uninitiated. There's more than one way to do everything, so styles diverge drastically. Perl coding tends to be a bit messy.
Python is a fresher, cleaner script language than Perl, and is these days preferred by many as a scripting language. It's fun to program in, it gets things done and because it's been around for a few years, lots of people know it. Python is found behind/inside a number of Linux system utilities.
Groovy leaves Perl and Python in the dust when (a) the environment already makes use of a JVM and/or there's a requirement to use existing Java code, including libraries. So far so good. Groovy is not blazingly fast, but faster than Python. Being dynamically typed, it's "fun" and "easy" to program in a way that Java's not.
But then came Scala. Scala is like Java on steroids. It is statically typed so it's not quite as "fun" to program as Groovy, but it has type inference so often you can leave off the types and the compiler can figure them out. Scala works really hard to make the most of types; it does generic types a lot more seamlessly than Java. It dispenses with a lot of Java's boilerplate, so Scala programs are typically about 30% shorter than similar Java programs. Scala runs on the JVM and interfaces pretty well with Java code. It also runs about as quickly as Java, which most of the other languages don't.
Finally in historic order, there's Clojure. Clojure is a Lisp derivative, so it has a programming style very different from languages you'd otherwise know, and it burns through a lot of parentheses! But Clojure runs on the JVM, is very compatible with all the rest of Java, and it's dynamically typed. You can use it as a scripting language or treat it like a compiled language... it's up to you. I find it fun to program in, and the fact that it's an almost pure functional language forces you to think in new ways about programming. It hurts your head at the beginning, but if you survive it's a very worthwhile exercise because you learn some techniques that will become more relevant (I think) in future programming.
In summary, it would probably do you good (put hair on your chest, if I may be so sexist) to learn one or more of these "alternative" / "scripting" languages. You may find them useful. Usually when there's something to be hacked up quickly in my project, I get the job because all my colleagues only know Java, and by the time they finish setting up their class framework I'm already done.
Quote:
so why don´t I just stick with java
and be good at ONE language instead of
having to switch between 2 languages
and their syntax.
This seems like a more general question about learning programming languages than learning a new language (Groovy) which runs on top of the Java Virual Machine.
Here's a question:
Suppose you are learning a foreign language because you want to be fluent in multiple languages so you can converse with many people. You're learning German right now, but you're getting good at it, but you also want to learn Spanish. Would you just suddenly forget German if you start to learn Spanish? If you are indeed worried that you will, what would you do?
If you were going to learn Groovy, but don't want to forget how to write Java, then why not continue to use both languages at the same time?
One of the things about being a programmer is going to be learning to adapt to new technologies as they come along. It's a good thing to be able to learn new languages, as it's going to be a skill that's going to be very useful in a field which is constantly changing.
Why don't you code your desktop apps in groovy too? Just because groovy is the choice of a web framework (grails) doesn't mean that you can't use it for desktop apps.
Indeed, it is great for desktop apps too. It's more a matter of dynamic or static languages...
In my opinion, it is quite good to have for each task the right language at hand. So go ahead and learn groovy - the result will be that you'll miss groovy features when you try to use java again ;-)
I would say in general in this field it's always good to be learning. I try constantly to learn new concepts to add to my toolbox, while getting better at the core things I'm interested in like Java. I recently purchased a book on learning Clojure - another functional language for the JVM.
The downside to learning something without using it every day is that some details don't stick in your head. That said, I'm glad I spent some time with Clojure; the important stuff stuck and I know I can quickly look up the details if and when I need to. You may want to take a similar approach to Groovy.
The Java platform is slowly starting to change direction to one where the JVM is targeted by multiple source languages (a trick .net has been showing off since day 1, but it's taking Java a while to catch up there). The Java7 classfile format is even adding a new instruction to make these dynamic languages work faster.
If you want to keep yourself current, then learning Groovy is a good way to do it, without abandoning all your investment in the Java platform.
Furthermore, Groovy (and Grails) is now maintained by SpringSource, so its popularity is only going to increase.
Going from java to groovy isn't a lot of work. No where near what would be needed to move to a less Javaish language like clojure.
I really like groovy for one-off apps and for scripting existing java code. I've used it to parse data from REST calls and feed the data to a JMS queue. I've used it to create scrambled test data for a partner from our production data. For stuff like that it is amazing.
If the goal is to learn a dynamic language to add to the toolbox, Python and Ruby are both good choices. They run on the JVM and have native versions. Both are well supported on a large number of platforms.
If the goal is to learn an alternative JVM language, groovy is an excellent choice. Both Scala and Clojure would also be good choices.
I used to stick to the "learn a new language every year rule" from The Pragmatic Programmer, but that was before I had kids. Now I learn a new building toy every six months.
First of all I'm this is a highly subjective question.
In my humble opinion it is worth learning a new language especially if it varies in paradigms (as is the case with groovy). I'm fairly young myself so for me learning a new language is not a much of hassle but the way I see it if you like the language, you estimate that coding in language X will be profitable you should learn it.
It won't hurt your resume.
It won't make your head hurt (much).
The only problem is, will you use it. You need to use a language to become good at it. If you are going to learn it now and never use it tomorrow it probably ain't worth learning it.
Learning something new does not take away something you already know. You may be a bit rusty when you get back into Java, but it'll come back real quick.
Also--
I'm not a Java guy, but I believe Groovy targets the JVM. If this is the case, then programming in Groovy will make you a better Java programmer, because you'll still be targeting the same framework as Java (the language) so you'll still continue to gain experience with the Java libraries. Knowing the available libraries is what really matters, not how well you know every minute detail of a particular language.
I find that by learning new languages, I always end up learning new ways to think about problems. Each language guides you into solving problems in the way most easily expressed by the language. Learning new languages only makes you stronger all around because you learn new ways to solve problems.
You might have to re-orient yourself with the libraries after a long time away from a language, but even then it's not a huge ordeal - just more frequent google searches, etc.
The benefits, however, are worth it. I recently did some functional programming for the first time and it really taught me a lot of different ways to think about certain situations. I find myself now using some of C#'s functional aspects and it makes my code a lot cleaner in some cases. The bottom line is; if your going to do this for a living you are going to want to learn more than one language, have you ever met a mechanic that only knew one make and model of car?
It's always good to learn a new language to be a better programmer. Groovy is a natural choice for java programmer - easy to learn and you can still use your all java knowlege.
Groovy is a dynamic language, after try to learn any functional language (like Scala). With this experience you will see java from different perspecitve. Some task that was painful in Java will be trivial in Groovy/Scala.
you can program desktop aplication with Griffon whose language of choice is Groovy, give it a try
If you are looking for online help, check this websites:
for Groovy
for Grails

Adding a language to the AVM2

I'm interested in making a language to run on the AVM2 and I'm looking for advice on where to start. I do realize that this is by no means a trivial task, but I would like to give it a try and at the very least learn more about implementing a language along the way.
I have messed around with ANTLR and have been reading up on syntax issues for language development. What I'm looking for is advice on a path to take or useful references/books.
For instance I would like to generate (script/manually) some very simple AVM2 bytecode and get that to run on the VM as a start.
Thanks
If you are not interested in Haxe, you will basically need to write your own compiler that compiles objects down to ABC (Actionscript Byte Code). The AVM2 Overview document available from Adobe on ABC and the AVM2 which should help you get started. It's a fairly thorough document but stay alert for a few typo's in the bytecode instructions.
You will also need to wrap the bytecode in a doABC tag as part of a SWF container. You can get more information from the SWF File Format documentation.
If you'd like a headstart on writing the data structures (optimised int formats, etc), feel free to checkout the code at asmock, a dynamic mocking project I've been working on. The SWF/ByteCode generation stuff is a bit messy but there are IDataOutput wrappers (SWF, ByteCode) that might come in handy.
Project Alchemy by Adobe can be a good reference
http://labs.adobe.com/technologies/alchemy/
How did it go?
I'm also interested in doing a Java to AVM2 compiler...
Do you have any published code?
Take a look at Haxe: it is an open source language that can target different platforms, including the AVM. You can dig into the SWF compiler source code to get some inspiration.