Hello there. I’m Taroven, the author of the continued versions of EventHorizon (hereafter known as EH).

In this blog, I’ll be going over everything EH – How to use it for maximum effect, customize it beyond your wildest dreams, and even use it for things that you had no idea it could ever do.

But first…

What the heck is EventHorizon?

EH is, in short, a combat monitor. It shows casts, cooldowns, buffs, and debuffs. Rather than needing to look at 3 things at once (cast bar, cooldown monitor, and buff/debuff indicators), EH allows you to see every bit of relevant information about a spell in a single, simple bar.

Most addons use percentages to show what’s going on. This means that the following happens:

Spell #1 has a 30 second duration. When it’s first cast, its bar reads full. When it has 15 seconds remaining, the bar reads half. Easy enough.
Spell #2 has a 6 second duration. When it’s first cast, its bar reads full. When it has 3 seconds remaining, the bar reads half. Wait a second… This means that the only way to tell which will expire first if we freeze with both spells at 50% is by looking at the number of seconds remaining (if they’re even displayed) or by resuming and watching which one moves faster.

Enter EventHorizon, stage left. EH tracks time itself. All the information it shows is overlaid on a common time scale, meaning you see everything in relation to everything else. The difference is incredible:

Spell #1 has a 30 second duration. When it’s first cast, its bar ends at 30 seconds. When it has 15 seconds remaining, the bar ends at 15 seconds.
Spell #2 has a 6 second duration. When it’s first cast, its bar ends at 6 seconds. When it has 3 seconds remaining, the bar ends at, you guessed it, 3 seconds.

This needs a picture or two to really show what I mean. Here’s an example showing the essentials on a Resto Druid.

As I mentioned previously, every bit of information about a spell is relayed on a single bar. Notice that everything is neatly aligned – I have one second remaining on Lifebloom. A little under 12 seconds remain on my Swiftmend’s cooldown. Rejuvenation still has about 6 seconds (two ticks) remaining. I just finished casting Nourish.

Wow. That was easy.

Let’s take it by the numbers.

1. Past: EH shows casts, expired spells and cooldowns, and ticks that have already happened here. The default is 3 seconds, plenty of time for most anyone. I use one second, personally.

2. Present: Otherwise known as the “Now Line”, the current point in time. An EH newbie will stare here – Anyone who is used to EH, though, looks at…

3. Future: What will happen. Contained here is the core of EventHorizon – Everything in relation to everything. Predicted spell ticks, cooldowns, buff and debuff durations, you name it. If you’ve ever had trouble deciding what to cast and when, read on. The default is 12 seconds from now.

4. Skill Icons: A simple show of what the bar is tracking.

5. Stack Count: Overlaid on the icon is a traditional stack counter. It shows – surprise – how many stacks of the spell are currently active.

6. Duration: The time left on a buff or debuff. EH directly watches your spells, so this will always be accurate to the millisecond. If a spell is dispelled or the target dies, the bar goes poof. If a spell is extended or refreshed (even via another spell) the bar will do likewise.

7. Tick Markers: Any DoT or HoT spell may have its ticks predicted in an easily readable fashion. EH tries its best to keep these predicted ticks accurate, catching when a tick happens and doing a little math to make sure the others line up. When Patch 3.3 hits, it will even track the effects of haste to make sure you have the most accurate possible information.

8. Cast Timers: EH keeps track of everything related to a spell, including its cast time. Again, this uses actual game information – Casting times use the game’s API to make sure they’re accurate.

9. The Recast Line: Another unique feature of EH is that it lets you know the best time to refresh an aura that has a casting time. The last known cast time of the spell is remembered and subtracted from the bulk of the bar, letting you keep a spell’s uptime near 100%.

10. Cooldowns: A good combat monitor isn’t complete without good cooldown tracking. Again, the game’s API is used to provide the most accurate information. In addition, if an effect’s cooldown isn’t provided by the game (How’s that Grim Toll looking?) EH will do a pretty good job of tracking it anyway.

Not shown in the shot:
Supports every class and spec out of the .zip: EH has been custom-tailored over the past year to let you use it on both your Survival Hunter and Disc Priest without skipping a beat. It does this by watching your class, spec, and glyphs – No setup required.
Global Cooldown: A line, not unlike the Now Line, that moves with your GCD. Unobtrusive and natural are the names of the game.
Channeled Spells: EH tracks channeled spells quite accurately – Including tick markers. Warlocks, Drain Soul was never this easy to use.
Internal Cooldowns: Yep, EH tracks those too. The hidden cooldowns on trinkets and certain talents/spells can be tracked accurately.
Glyph Refreshes: A very unique example of how EH helps in every possible way. If you’re using certain glyphs (Backstab [Rogue/Rupture], Shred [Druid/Rake], Starfire [Druid/Moonfire], etc) EH will show the remaining number of glyph-based extensions a spell has remaining via the stack counter. This information is always accurate, even when you’re switching targets constantly.
Unique Buffs and Debuffs: If a spell is unique per target and you happen to use it as part of your rotation (Feral Druids, I’m looking at you and your designated Mangle/Trauma bots), EH will show a faded bar letting you know when someone else has supplied it already.
Related Spells and Secondary Effects: Not every spell has its own buff or debuff. For example, Nourish in the example above also tracks Nature’s Grace. A Holy Priest’s Lesser Heal tracks Inspiration (and Ancestral Fortitude), while Disc gets Grace tracked via Penance.
EventHorizon_Vitals: Vitals is a little plugin for EventHorizon that tracks some other useful information next to EH’s frame. It shows your current power (mana, rage, energy, vehicle power, what have ye), weapon enchant durations, combo points, runes, and a few other niceties. Vitals isn’t bundled with EH itself because it is not universally useful, but is definitely worth checking out.
Endless Customization: EH has no in-game configuration, and for very good reason – If it were offered, it wouldn’t be anywhere near as flexible as it is now. It would also be nearly impossible to set up… and if you’ve never lost your settings because of a nasty crash or game-breaking bug, you’ll thank me later. Settings can be handled via a simple configuration file contained in the EventHorizon directory, and trust me when I say there are quite a few to tweak at your leisure. The defaults are quite satisfactory for most anyone if you dislike dealing with text.

Update 11/06/09: Here’s another shot, from Wimpface.

Wimpface's EH setup. Shows off all the major elements, and a lovely color scheme and layout to go along with it.

That’s all for now. Stay tuned for the next episode of Taroven’s EventHorizon insights.

Next – EventHorizon Course 2: What EH Is Not

You can download EventHorizon here.
If you enjoy the addon, remember that donations are what keeps it alive and evolving. I no longer play the game any more than necessary for testing purposes, and cannot spare the money to keep my WoW account running for that purpose alone.