Firefox 3.0.1 and GMail: Gray Background???

29. September, 2008

Am I the only one who gets a gray background on many websites after the update to Firefox 3.0.1?

Update: Apparently so. If not, browse to about:config and search for “browser.display.background_color”. In my version of FF, that was set to #C0C0C0 for some reason (when it should have been #FFFFFF).


Installing Eclipse 3.4.1 Despite p2

29. September, 2008

If you’re, like me, one of the unlucky ones that aren’t on p2’s friends list (translation: Eclipse p2 provisioning causes you an endless stream of pain and suffering), then you can’t install the 3.4.1 patches because p2 won’t let you.

There are several ways to deal with this. One of them is to delete your workspace’s .metadata, your Eclipse install and start from scratch, installing all plug-ins again, etc., always hoping that p2 doesn’t mess up until you’ve installed everything.

The other way is a workaround. It needs a bit of disk space and discipline. Do this:

  1. Leave your original Eclipse install alone. Specifically, never ever use the menu “Software updates…” again! Never. I mean it. Disable the entry if you can.
  2. Install eclipse again in a new place. This must be a standard install (not a shared one!!!)
  3. Do not start this install! Specifically, do not attempt to add all your update sites to this base template! Just unpack it and rename the “eclipse” directory to “eclipse-template”.
  4. Copy “eclipse-template” to “eclipse-install”.
  5. Start eclipse-install. If you worry that you might accidentally start the template once in a while, rename “eclipse.exe” to “eclipse.exe Is this install”.
  6. Download the 3.4.1 updates.
  7. Exit eclipse-install.
  8. Use your favorite file copy tool to copy all new files and directories in eclipse-installplugins and eclipse-installfeatures to your working copy of eclipse.
  9. Start your working copy.

Installing and updating plug-ins works in a similar way:

  1. Delete eclipse-install and recreate it from eclipse-template.
  2. Start eclipse-install.
  3. Open the install software dialog. Add the update site. You may be tempted to add the update sites to eclipse-template. Don’t do this! As soon as p2 can see more than one update site, it will eventually mess up in the dependency calculation.
  4. Install the plug-in.
  5. Create a directory for your new plug-in in the driectory “dropins” of your working copy of Eclipse.
  6. Copy the new files and directories from eclipse-installfeatures and eclipse-installplugins to the new directory below “dopins” in your working copy of Eclipse.
  7. If you need to install more than one plug-in, start with step 1. After you have installed anything in eclipse-install, the Eclipse instance is tainted and shouldn’t be used again.

That’s all folks. At least until the p2 guys fix the many bugs in their code. Which will probably in the Eclipse release in 2010.

That’s not because I believe that the p2 guys are stupid or lazy but because this kind of product just takes three years to mature and they started in 2007, so the first working version can be expected in 20010.


Stack Overflow Launches

18. September, 2008

Stack Overflow is a Q&A site for programmers. If you’re looking for an answer to a question or if you know a lot and can’t really fill your needs to help in your current position, have a go at it.


Amiga Forever 2008

8. September, 2008

I have the set for a while now (thanks Michele!) and after reading the announcement elsewhere, I’d like to remind all you Amiga fans out there that the 2008 release of Amiga Forever is ready. Did you know that Andy Warhol (yeah, that Andy Warhol) gave a demo of the system when it was launched 1985? If not, grab the premium edition and watch him do his thing with Marilyn Monroe (or rather a picture of her).


How To Launch Software

5. September, 2008

If you’re still wondering if “big bang” software releases are a good thing, read this.


The Space Between Two Characters

31. August, 2008

If you’re claustrophobic, you’re afraid of confined spaces. If you’re a software developer, you can be afraid of non-existing space.

When it comes to editing text, we usually don’t think about the space between the characters. There simply isn’t any. When you write a text editor, things start to look different. Suddenly, you have a caret or cursor which goes between the characters and that space between two characters can suddenly become uncomfortably tight.

Fire up your favorite text editor, Word, Writer, whatever. It has to support character formatting, though. Now enter this:

Hello, world!

If in doubt, the bold text ends before the comma and the italic part starts with the “w” and ends with “!” including both.

Now move to the “e” and type “x”. What do you get?

Hxello, world!

Piece of cake.

Now move to the “H” and type “x”. What do you get? Is the new x bold or not? Do you get “xHxello” or “xHxello“? How about typing “x” after the “o” of our abused “Hello”? Is that new x bold or not? If it is, what is the most simple way to make it non-bold? Do you have to delete the comma, do you have to go through menus or toolbars or is there a simple, consistent way to add a character inside and outside of a formatted range of text?

Let’s go one step further. Add a character after the “!”. Is it italic? If not, you’re lucky. If it is … what’s the most simple way to you get rid of the italic? If you press Return now, will the italic leak to the next line? If not, how can you make it leak? If that italic is the last thing in your text, can you add non-italic text beyond without fumbling with the formatting options?

There is no space between two characters and when you write a text editor, that non-existing space is biting you. Which is actually the problem: There is no consistent way to move in and out of a formatted range of characters.

The naive attempt would be to say “depending on the side you came from, you’re inside or outside.” So, if we have this (| is the cursor or caret): “Hello |world” and you type something, the question is: How did the caret end there? Did it come from “w|o” and moved one to the left? Or from “o| ” and move one position right?

That works somewhat but it fails at the beginning and the end of the text plus you’re in trouble during deleting text. What should happen after the last character of “Hello” has been deleted? Should that also delete the character range or should there be an empty, invisible bold range left and when you type something now, it should appear again? If you keep the empty invisible range, when do you drop it? Do you keep it as long as the user stays “in” it? Or until the document is saved? Loaded again from disk?

It’s a mess and there is a reason why neither Word nor OpenOffice get it right: You can’t. There is information in the head of the user (what she wants) but no way for her to tell the computer. Duh.

That is, unless you start to give the user a visual cue what is going on. The problems we have is that there is no simple, obvious way for the user to say “I want …” because there is no space on the screen reserved for this. We barely manage to squeeze a caret between the characters. There is just not enough room.

Well, there could be. A simple solution might be to add a little hint to the cursor to show which way it is leaning right now. Right. How about “A|B“? Here, you have three options. Add bold, italic and normal.

In HTML, this is simple. I’m editing this text in Firefox using the standard text area. What looks fancy to you looks like this to me: “<b>A</b>|<i>B</i>”

And this is the solution: I need to add a visual cue for the start and end of the format ranges. Maybe a simple U-shape which underlines the text for which the character format applies. Or an image (> and < in this example): “>A<|>B<“. And suddenly, it’s completely obvious on which side of the range start and end you are and what you want. You can delete the text in the range without losing it or you can delete both and you can move in and out of the range at will.

The drawback is that you need to keep that information somewhere. It adds a pretty huge cost to the limits of a format range. I’ll have to try and see how much that is and if I can get away with less by cleverly using the information I already have.

Also, it clearly violates WHYSIWYG. On the other hand, we get WYSIWYW which is probably better for the user.


DecentXML 1.2

31. August, 2008

DecentXML 1.2, my own XML 1.1-compliant parser, is now available.


Text Editor Component and JADS

27. August, 2008

While working on DecentXML (1.2 due this weekend), I’ve had those other two things that were bugging me. One is that there is no high-quality, open-source framework with algorithms and data structures. I’m not talking about java.lang.Collections, I’m talking about red-black trees, interval trees, gap buffers, things like that. Powerful data structures you need to build complex software.

Welcome the “Java Algorithm and Data Structure” project – jads. I haven’t started opened a project page on SourceForge or Google Code, yet, but I’ll probably do that this weekend.

Based on that, I’m working on a versatile text editor component for Java software. The final editor will work with user interfaces implemented in Swing, SWT and Qt. It’s an extensible framework where you can easily replace parts with your own code to get the special features you need. I currently have a demo running which can display text, which allows scrolling and where you can do some basic editing. Nothing fancy but it’s coming alone nicely.

If you want to hear more about these projects, post a comment or drop me a mail.


Death Star in EVE Online

19. August, 2008

Apparently, a group of 4000 players of EVE Online have built a kind of a “Death Star” (a “titan ship” in the language of the game) to rule the game galaxy. Assembly took 8 months in total secrecy and the result was destroyed completely within 3 months.


Another Lesson on Performance

19. August, 2008

Just another story you can tell someone who fears that “XYZ might be too slow”:

I’m toying with the idea to write a new text editor. I mean, I’ve written my own OS, my own XML parser and I once maintained XDME, an editor written originally by Matthew Dillon. XDME has a couple of bugs and major design flaws that I always wanted to fix but never really got to it. Anyway.

There are various data structures which are suitable for a text editor and some of those depend on copying data around (see gap buffers). The question is: How effective is that? The first instinct of a developer is to avoid copying large amounts data and to optimize the data structure instead.

After years of training, I’ve yet to overcome this instinct and start to measure:

    public static void main (String[] args)
    {
        long start = System.currentTimeMillis ();
        
        int N = 10000;
        for (int i=0; i<N; i++)
        {
            int[] buffer = new int[1024*1024];
            System.arraycopy (buffer, 0, buffer, 1,
                buffer.length-1);
        }
        
        long duration = System.currentTimeMillis () - start;
        System.out.println (duration);
        System.out.println (duration / N);
    }

On my computer at work (which is pretty fast but not cutting edge), prints: “135223” and “13”. That’s thirteen milliseconds to copy 4MB of RAM. Okay. It’s obviously not worth to spend a second to think about the cost of moving data around in a big block of bytes.

Lesson: If you’re talking about performance and you didn’t measure, you have no idea what you’re talking about.

Still not convinced? Read this.