[kronolith] Colorization by tags

[Michael J Rubinsky]

Quoting Ulrich Eckhardt <uli-ho at uli-eckhardt.de>:

> Am 09.06.2011 19:46, schrieb Michael Rubinsky:
>> The slightly longer answer: In the "old" kronolith (from Horde 3),
>> there *were* no tags. Tags were introduced in Horde 4. Kronolith
>> previously allowed setting a single category to an event, and the
>> event's bubble would be colored per the user's category preferences.
>> With tags, there are a number of reasons why this won't work. See the
>> discussion on Ticket: 9657 and Ticket: 7480 for a more detailed
>> explanation.
>
> If I understand the tickets correct the main problem with keeping a  
> per-tag-color implementation is how to handle the coloring when an  
> event is tagged multiple times.

That's part of it - along with the fact that both events AND calendars  
can be tagged. How would the calendar's tag be taken into account?

Though the bigger issue is performance. Having to query the tag system  
each and every event on a calendar view would be a huge performance  
hit. Not to mention having to query the pref system for tag colors as  
well.  The tag system in Horde is fundamentally different then the way  
categories were handled. In fact, we have explicitly added code that  
explicitly does NOT lookup event tags when building the various  
calendar views.

>
> How about a simple approach? The first tag in the list will be used  
> for coloring and the color of all following tags will be ignored.

That doesn't sound very intuitive. Plus, there *is* no "first" tag.  
All tags are created equal...

> Since only one tag per event needs to be checked for the color there  
> shouldn't be a too big performance hit.

The larger part of the performance hit is doing the tag lookup per  
event, though you are right, having to query the pref system for color  
as well would be very bad.

The only acceptable way of displaying the colors, IMO, would be  
something similar to custom flags in IMP. Each event bubble would show  
one dot of color for each tag. Though, as stated, the performance  
implications are too high to implement this.

I could be convinced to implement it, with a config switch to turn it  
off if the installation does not have many users, but to be honest,  
that would be very low on my list and not likely to happen without  
being sponsored (or someone else providing a patch).

  So the old functionality of
> Kronolith from Horde 3 would be restored without the danger of a too  
>   colored calender.
>
> I really miss the possibility to select a color by tag or category  
> for an event since this gives a fast and clear summary at first  
> glance.

The only way of doing this in Kronolith 3.x would be to have a  
separate calendar for each desired color. FWIW, this is how many other  
calendaring applications handle this as well.


-- 
mike

The Horde Project (www.horde.org)
mrubinsk at horde.org