jQuery Draggable/Droppable: Revert on drop

Background:

At work we are currently in the process of creating a general data hub which is easily expendable and configurable. It’s already in use exchanging EDI messages (EDIFACT) for a supplier on the danish electricity market.

For the configuration we settled on a GUI where you could drag different kinds of data manipulations into the data flow and this is all implemented in HTML with jQuery.

The problem:

Upon drop I had to use Ajax to ask the server if it was ok to drop the draggable. Since Ajax is asynchronous the drop event would return before the Ajax actually had finished. I decided that I didn’t want to force the request to the server to be synchronous instead I wanted the ajax success callback to be able to do the reverting.

Upon searching the net, the closest thing I came to a solution was defining a callback function for revert on the draggable, and this functionality isn’t even documented by the time of this writing.

The solution:

After playing a bit around I found an acceptable solution. I’ve created a small example reverting a drop using a confirm where you can test it (and see the code).

Screen real estate

Gnome global menu and Gnome Do in action
Gnome global menu and Gnome Do in action

My last laptop was the IBM Thinkpad x40 with a 12” screen and a resolution of 1024x768. I used it both private and for work for over five years several hours a day and wore down three batteries in that time. With such a little screen you find yourself exploring ways to get the most out of your screen. Since I prefer the keyboard over the mouse any day I’m not forced to have big icons and menus all over the place.

Here are the steps I’ve taken (things I’ve removed) and how get things done (without them).

Firefox

Press “View / Toolbars / Customize…” and remove anything except from the back, forward, location bar and search bar. Also select “Use small icons”. To stop loading a page just hit escape, to reload use F5 and home use Alt+Home. To get to the location bar hit Ctrl+L and to get to the search bar hit Ctrl+K. I also hid the Bookmarks toolbar (because the suggestions in the address bar usually gives me what I want… alternative you can give bookmarks tags (keywords) which you can type in the address bar to open the bookmark.

Bottom panel

I’ve removed the bottom panel on my Ubuntu installation since it had nothing I’d ever use. Hide all open windows or “Show desktop” is easily accessible using Ctrl+Alt+D. I never used the Trash icon i really rarely delete anything and when I do I usually hold shift while doing so (which skips the trash can) which leaves me with the “Window list”. The window list show the open windows on all workspaces and although I use tabs whenever I can get away with it (Gedit, firefox, terminal and sometimes Nautilus) I still usually have about eight open windows spread over my six workspaces. I’ve come into the habit of using the same workspaces for the same tasks (often one application). Example:

  • Workspace 1: Email
  • Workspace 2: Browsing
  • Workspace 3: Terminal
  • Workspace 4: Virtual machines
  • Workspace 5: Documents using OpenOffice or PDF using Evince
  • Workspace 6: Editor (mostly emacs but somtimes gedit).

This way I alwas know where the application I want for the task at hand is. I use the keyboard shortcuts (Ctrl+Alt+arrow keys) to get to it. I always know where to look for an application. Having all applications on the same workspace and use Alt+Tab or the window list I would have to use my eyes to locate and identify the application I want. So I find this method much faster. Just to be on the safe side I put an other applet called “Window Selector” in my panel in case I ever found myself in need of being able to select a window with the mouse. I sometimes use to show me a list of all the applications I’ve opened.

Gnome do

I can’t remember excatly how why or when I started using Gnome-Do but it is one of those things you didn’t know you needed until you started using it. It is one of the most powerful and versatile tools I’ve ever used on my desktop. Although its not there yet it certainly could be for the desktop whan a terminal is for a server. At the moment I’ve mostly use it to start applications, play, pause and skip music and start, stop, suspend and snapshot virtual machines in Virtualbox. Though I’m pretty sure the use of Gnome-Do will keep growing on me.

Global panel

After I found my self not using the application menu to start stuff anymore I decided to remove it from my top panel to get the extra space and test gnome-global-menu. I belive the gnome-global-menu project was inspired by Mac but whether Apple came up with the idea themselves or they got inspired somewhere else I don’t know. I the top of this post you can see how my desktop looks at the moment (just installed Ubuntu Lucid).

php: Could not startup.

Informative error message… NOT.

I’ve installed php-gtk on a machine and got the above error when trying to start php from cli via ssh.

After a while it suddenly hit me that I hadn’t forwarded X when I logged in via ssh. After that I was able to use php again. php with php-gtk is unable to start without a X server.

Php-gtk deb packages for Ubuntu Karmic

At work I was assigned to package some software to make it easier to distribute and update. One of those software packages was php-gtk which with one patch to the build/configure files now cleanly builds on Ubuntu. You will be able to find the package on my Ubuntu PPA. You will be able to find builds for both 32bit and 64bit platforms.

I’m also in the process of uploading packages for FriFinans which is an Open Source economy / accounting application. This should be easier… lets see how it goes :)

Running Tales of Monkey Island with Wine

I’m a proud adventure game fan boy and have enjoyed countless hours in the company of Monkey Island, Day of the Tentacle, Legend of Kyrandia among others. ScummVm have helped to re enjoy many of these titles after replacing my preferred desktop system with Linux.

When the news reached my ears about “Tales of Monkey Island” I was very exited. But also nervous if would be able to play these episodes without Windows… but fear no more.

It is possible!

My system:

  • Nvidia graphic card
  • Ubuntu Karmic 64bit
  • Wine from special package archive (to get native pulse audio support)

The episodes install on all Wine versions I’ve tried on so far (several guides on the internet suggests not to check for DirectX, though I haven’t personally experienced any difference). When the game starts you are asked to provide the serial number. In this phase I’ve encountered trouble several times. Earlier providing the serial number only worked in old versions of Wine (like version 1.0) but this time I got it working with the newest version of Wine (which at the time was 1.1.32). Also I had to delete my .wine folder in order to reset wine because I apparently had some IE6 leftovers in there which otherwise would mess up the registration.

After activating the episodes you need to install D3DX9_41.dll into .wine/drive_c/windows/system32. Remember Linux is case sensitive so it is possible to have several different files with the same name except for the case. If it still doesn’t work make sure you only have one d3dx9_41.dll and that it’s not the one provided by wine (which won’t work).

Now the game starts… but for me the sound jittered. After looking around I found that it was ALSA interface in Pulseaudio which kept loosing the “connection” re initiating it. My saviour was Neil Wilson who have packaged Wine with a native pulseaudio audio plugin. This did the trick for me and Tales of Monkey Island is now very much playable at least for me :D