Menus...implementing them (ipod web app) Monday, 19 October 2009  
Still busy working on my Motif replacement for CRiSP. Much of the grunt work was done a long while ago, but menus were the thing I put off until a couple of months back.

Implementing menus is frustrating. (The input field widget took about 2 days to implement from start to finish, and the result is more functional than what it replaces). By contrast, menus have taken a couple of months. Much of the original code worked u front.

What makes menus tricky are a number of things but mainly related to input focus and 'appearing to do the right thing'. Menus can popup with a mouse, and then be navigated into sub menus with the mouse or keyboard. I delayed getting the input focus problems solved until late in the implementation, which, in turn, broke much of the existing logic. (Events firing to the menu button popping up the menu or the menu or menu items, etc). Just as bad was restoring the status quo when selecting a menu item or dismissing the menu.

To make life palatable, I have a nice suicide-timer - after 25s, a child does a "kill -9" on the parent, which avoids the tedium of trying to unwedge the X server.

Its all very close, and am just busy ensuring all combinations work properly. (Mainly nested menus as they popup/get dismised).

Many of the problems are my own misunderstandings: I spent a good few days trying to get XGrabPointer() to work for me, only to eventually realise what I needed was XtAddGrab(). [Someone on a forum mentioned that if you weren't confused by XGrabPointer/XGrabPointer, then you didnt know what you were doing!]

XGrabPointer is to do with freezing the X server, typically used for drawing type apps. For menus, you sort of need a mixture of the two. (You want to intercept a menu dismissal when you click outside of your own application).

(I was debating using the iPod Touch to fix my X server hanging problems, e.g. have a web server running, which responded to trivial HTTP requests, and on receipt of a request, could douse the rogue hung application).

Ok, here it is - an ipod touch web server to help debug X11 apps...

#! /usr/bin/env perl                                                          
use strict;                                                                   
use warnings;                                                                 
use IO::Socket;                                                               
sub main                                                                      
   my $sock = IO::Socket::INET->new (                                    
      LocalPort => 8080,                                                 
      Type      => SOCK_STREAM,                                          
      ReuseAddr => 1,                                                    
      Listen    => 10);
   while (my $client = $sock->accept()) {                                
           print "Killing hung app...\n";                                
           my $str = `ps ax | grep /home/fox/crisp_v9.5/bin.linux-x86_32/crisp`;
           next if !$str;
           $str =~ m/^ *(\d+) /;
           next if !defined($1);
           kill(-9, $1);

Posted at 22:33:04 by Paul Fox | Permalink
  dtrace update Saturday, 10 October 2009  
Not much to report; i have hopefully fixed compile issues on 2.6.31 kernels (havent proved on 2.6.32). It does get tiresome the tweaks from one kernel to another to prove it compiles properly.

Some people are reporting issues on GCC 4.4 and later glibc's. If you get these issues, let me know. glibc seems determined to break existing apps (GCC isnt quite so bad).

User space stack tracing is probably hosed because getting the user space stack, depending on the trap context is fiddly and something I hadnt finished.

Need to catch up on my crisp Motif work (it all works, but its not quite perfect enough to release the crisp code yet).

Posted at 15:53:04 by Paul Fox | Permalink
  Boo hoo... Tuesday, 06 October 2009  
Hard drive on my ftp server has gone - so that means some links and crisp downloads are out of action til I have a chance to put the backup into place and populate it with something useful, like, err, maybe an operating system.

As a BTW, I decided to implement 'inertial scrolling' on fcterm and crisp. So, you may find (eventually) a new release with the feature where the faster you scroll the wheel on the mouse, the faster it scrolls. (Works nicely on fcterm, but may need to do more surgery on crisp since it only works for X windows, and needs to work for Mac+Windows too).

Posted at 23:16:00 by Paul Fox | Permalink
  More Apple Insanity Sunday, 04 October 2009  
I wrote a short while back about the iPod Touch - nice hardware, shame about the software. I will continue my rant...

Sometimes, my movie playlists will play back to back, but mostly not. Its totally erratic, and simply feels like a 1st grader programming error. Its almost like an uninitialised variable is causing it to work or not. Sometimes switching it on/off helps, or a resync, but who knows.

Then, the other area of total insanity is the app store. The app store integration is brilliant - ability to browse, and waste a few minutes seeing whats available is great. Then you can download free software or pay for software.

But...why on earth does the ipod go into a mode where *no* applications will run? The startup screens almost show but then the app aborts or exits. Who knows what - because Apple decided not to show you a reason why the app quit. Then, some time later, they will all work again. This is clearly a bug in Apples firmware. I have downloaded maybe 15-20 apps, and I can believe some have bugs, but not on the initialisation of the app. Why it should go into "not going to run anything" mode and then recover, I dont know.

I downloaded an RSS reader - great software, but I am fearful it creates a lot of little files for the unread news - maybe thats tickling a bug; maybe the filesystem is fragmented - you cannot see the filesystem so you are SOL to know whats going on.

What is annoying is that lots of people on the web report the same thing and as far as I can tell, noone has clued up on the real causes, and Apple doesnt admit to this issue. Their 'walled garden' is full of street-corner muggers.

At least it plays movies and music - my main desire, but the app crashing is unforgivable. At least, some form of diagnostic tool to figure out what would be nice. Maybe thats a tool that needs to be written, or maybe I will find out on google somewhere what is going on.

Posted at 10:08:14 by Paul Fox | Permalink