I am attempting to write a program that will generate .agr files that can be loaded and manipulated in xmgrace. I've dissected an example file that has the kind of formatting I'm looking for, but I'm not 100% sure what every line does. A lot of the commands are self-explanatory for the most part, but is there a guide somewhere I can use to reference some of the more obscure lines like #reference date 0, #default sformat "%.8g", #r0 off, etc.?
I've looked around the grace website in both the user and developer sections as well as googling individual lines without much luck. All I'm looking for is basically a man page of xmgrace .agr files. The more low-level details, the better.
Any help would be appreciated!
I'm sure that you have already looked through all of the official documentation for Grace/xmgrace. This documentation doesn't give much information about the internals of the .agr files that xmgrace creates.
I have found in the past that creating your own files and studying them in a text editor is a good way to learn what each line does, but as you said it is not always possible to decipher everything.
A project that is doing something similar to you is pygrace.
Maybe if you look at the pygrace source code it will give you some further clues to fill of the gaps in your existing knowledge.
I've read many papers and source code about distributed system and there are many "duplica"s and "replica"s. It seems having the same meaning.
Is there any difference between these two words?
I'm having trouble finding any papers which refer to "duplicas" either in my paper archive or on Google Scholar, although I've found a bunch which say "duplicates"/"duplication". If that's what you meant, yes, they refer to the same thing.
I've been reading this reference: http://www.osdever.net/FreeVGA/vga/vgafx.htm
to learn VGA programming, but because I'm a student that just started learning about low level programming, I find it hard to understand. What does it mean when the reference says "scan"?
Especially in the "Split-screen Operation" section in the article, I'm not sure how "scan" is related to splitting the window.
I'd appreciate it if someone can explain briefly or link me to another reference where I can learn about it.
A Scanline is a single pass across the screen horizontally.
I want to read a ttf and draw a text with that font on a buffer. Even though there are libraries such as freetype, gd to do this task, I want to write my own code. Can you advice me on how to accomplish this task?
Unless you're one of the world's top experts on fonts, typography, and writing systems, the answer is simple: DON'T. TrueType/OpenType has a lot of tables you need to support for correct rendering, and even when using FreeType (which is an extremely low-level library), most people get it wrong.
If you need to do low-level, deterministic-across-platforms font handling, then at the very least, you should be using FreeType and libotf. This will provide you with access to the glyphs and outlines which you can then render however you like. In most cases though using your GUI system's text rendering routines will be a lot easier and less error-prone.
Finally, if you insist on ignoring my advice, a good RTFS on FreeType and Microsoft's online resources explaining the tables in TrueType/OpenType fonts are probably the best place to get started.
I would suggest you
Read all the TTF docs you can find
Find all the open source TTF parsers + renderers you can find, in many different languages, such as Freetype (c/c++), Batik (java), and anything else you can google for. Also George Williams' fontforge will likely be very helpful to you on your journey.
Rip apart all the programs you collected in 1. and see how they work. See if you can make a tiny small example program to do something simple, like dump the list of points for the outline of the letter "I".
Work on your rasterization. Start with something very simple, like rasterizing the letter "l".
The problem with TTF is that there is not a simple file format, and freetype handles a lot of crazy details for you. However if you don't care about portability, and you already have a specific TTF file you want to render, and you only care about a small simple alphabet, like Latin or Cyrillic, you might be OK.
Also you might want to check out a list of TTF documentation I linked to from my little project https://github.com/donbright/font_to_svg/
Not impossible, for anyone else tempted to try. I was curious about doing it because I like the DIY graphics approach where I allocate some memory and write into it, then save as a jpg or png. I pirated a bitmap font from giflib but that's strictly 8x8 pixels.
A few links:
`http://stevehanov.ca/blog/index.php?id=143`
`https://www.google.com/search?q=ttf+parser+c&ie=utf-8&oe=utf-8`
as R.. wrote the same time as i did in my comment, i would not to suggest to build another TTF-parser by your own. If you are eager to learn this very "spannende" field of Computer Science I would recommend "The Art of Computer Programming" Vol 2 from Donald E. Knuth. (it is Metafont, not TTF, but proven to be correct:-)
Does anyone know of a good steganography library I can use thats written in C or Objective-C? It would need to be used in a Mac OS X application.
My provocative answer will be that you should try to implement/learn some algorithms for image hiding/unhiding yourself. Sample algorithm of 3-bit image hiding into 24-bit image is very simple and consists of about 10 Python lines or so (of course it may be a bit more with C/Obj-C). And you will get not bad quality of stego image - about 87.5% of original quality. So check my blog article about this steganography method.
This stego decoding method is done in GPU pixel shader program for fast decoding procedure.
However encoding was done with Python script which after use was deleted ;P
But i think that encoding procedure is very straightforward and can be understood from my blog article. If any questions about my stego algorithm- feel free to ask.