An addon designed for RolePlayers. This addon makes messages in the chat frame sent to /s, /y and /e darker the further away the speaker is from you. This makes it easier to focus on players RPing closer to you when in busier areas.

It also provides options to highlight friends/guild-mates/party-members to make them stand out in the walls of text that occur when multiple people are chatting nearby, and to add prefixes depending on your familiarity with the speaker (Friend/Guild/Group/Stranger/NPC).

The addon disables itself during combat so that it doesn't interfere with gameplay and there are options to control whether or not it works in instances and raids (disabled by default). The addon disables itself when in pvp instances (not configurable).

Please Note: The addon works far better when you have nameplates enabled.
If you don't like having nameplates enabled outside of combat, tick the box in the addon's options (Esc->Interface->Addons->Darken Chat Messages) called "Toggle Momentary Nameplate Scan" - This will allow it to enable nameplates for a split-second at an interval to update distances for nearby players.

Current Features:

Darkening of chat messages by distance of speaker from player.
Prefixes for chat messages by Friend/Guild/Group/Stranger/NPC/Target/Focus.
Highlight-colors for Friends/Guild/Group.
Addon Communications to synchronize range/distance info between players.
High level of configurability. Check the options menu in Interface->Addons->'Darken Chat Messages'

Planned Features:

User-configurable colors for messages from friends/group/guild.
More customization of chat frame messages for clarity when RPing.

Limitations & Known Issues:

Range-finding of arbitrary units in WoW is extremely difficult by design (to prevent cheating).
This addon uses a variety of means to determine how far speakers are from you, but none of those methods are completely reliable or accurate - This is a hard limitation of WoW's Lua API.

The addon works best when you have nameplates enabled, so that it can use them to determine speaker distances. When nameplates are disabled, the accuracy of the system drops dramatically as it is forced to rely on checking units you are targeting, focusing, mousing over, or in a group with.

There is an option in the addon's config UI (under Interface/Addons menu) that lets the addon periodically enable nameplates for a split-second so that it can grab distance information for nearby players without cluttering your screen.

WoW Classic Support:

Might be compatible but hasn't been tested yet.

Languages supported:

English
Other locales to follow in later versions. The addon works fine with any language, but the options UI will be in English only for now.

Credits:

This addon uses the following libraries:
LibStub
LibRangeCheck
ChatThrottleLib

KVCD - RP Chat Clarity - Darken Chat Messages by Speaker Distance