Archive for Allgemein
November 28, 2009 at 12:26 pm · Filed under Allgemein, Javascript
Coverflow has become a de facto visualization standard for the presentation of collections of images, be it covers or portraits.
There are a number of implementations for usage on web pages (e.g. this one) but the usable ones require Adobes Flash and thus won’t run on the iPhone.
When looking for HTML5 canvas based implementations I found this promising implementation based on the YUI library.
Though workig, it has three major drawbacks: It is rather overengineered and difficult to tweak, it uses YUI (whereas I prefer the more lightweight jQuery) and it performs poorly with image sizes bigger than thumbnails.
After trying to change the code for a while I decided to do a reimplementation in jQuery. The result can be seen on the MomoFlow demo page. Here are two screenshots:
CoverFlow using canvas and jQuery
Quicklook mode
The used 3D transformation is superbly described on the YUI blog .
My implementation caches the rendered canvases per rendering angle. Further speed increments are made possible by adjusting the mesh width used for the slicing transformation depending on the achieved framerate.
The result performs beautifully in recent Safari, Chrome and Opera, decently on Firefox. It also works flawlessly on the iPhone. Keyboard control is coming soon.
I do still need help on IE, maybe the image composition is too demanding for ExplorerCanvas?
The code is available on github: http://github.com/momolog/momoflow.
Comments and improvements are very much welcome!
Oktober 21, 2009 at 11:03 am · Filed under Allgemein
Since MySQL does neither have real check constraints nor a way to raise an exception in a stored procedure, we found it not instantly obvious, how we could *reject* a certain row on insert, based on a certain condition.
A nice way we found was to set the value in question to NULL, based on the condition and let the NOT NULL constraint do its work.
ALTER TABLE sessions MODIFY session_id varchar(255) NOT NULL;
DROP TRIGGER IF EXISTS check_sessionid;
DELIMITER $$
CREATE TRIGGER check_sessionid BEFORE INSERT ON sessions
FOR EACH ROW BEGIN
IF NOT NEW.session_id REGEXP '^[[:xdigit:]]{32}$' THEN
SET NEW.session_id = NULL;
END IF;
END;
$$
DELIMITER ;
The trigger will let any 32 character string with only HEX characters for the column session_id pass and rejects the rest.
> INSERT INTO sessions (session_id) VALUES ('ffffffffffffffffffffffffffffffff');
Query OK, 1 row affected (0.01 sec)
> INSERT INTO sessions (session_id) VALUES ('fffffffffffffffffffffffffffffffg');
ERROR 1048 (23000): Column 'session_id' cannot be null
Happy triggering.
Oktober 18, 2009 at 5:46 pm · Filed under Allgemein, MacOSX, Note to self, Ruby
Suche nach Wort unter dem Cursor in vim: #.
jssh ist eine JavaScript Shell, die den Firefox per Port 9997 fernsteuerbar macht.
Download z.B. hier.
y erzeugt einen YAML dump auf der Rails console, mehr dazu hier.
=3D ist ein escaptes “=” in quoted_printable.
sudo /usr/libexec/locate.updatedb aktualisiert unter MacOSX sofort die locate Datenbank.
rake db:migrate:redo führt unter rails die letzte Migration rückwärts und sofort wieder vorwärts aus, so dass sich die Vorwärts-Action korrigieren läßt
ack -Q bringt ack dazu, literal, also ohne RegExp zu suchen.
Mai 19, 2009 at 9:57 pm · Filed under Allgemein
Kampagne gegen Terroristen in Deutschland. Sehr schön.
