Color mentions to match the mentioned users color

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - Major: Added "Channel Filters". See https://wiki.chatterino.com/Filters/ for how they work or how to configure them. (#1748, #2083, #2090, #2200)
 - Major: Added Streamer Mode configuration (under `Settings -> General`), where you can select which features of Chatterino should behave differently when you are in Streamer Mode. (#2001)
+- Major: Color mentions to match the mentioned users. You can disable this by unchecking "Color usernames" under `Settings -> General -> Advanced (misc.)`. (#1963, #2284)
 - Minor: Made BetterTTV emote tooltips use authors' display name. (#2267)
 - Minor: Added Ctrl + 1/2/3/... and Ctrl+9 shortcuts to Emote Popup (activated with Ctrl+E). They work exactly the same as shortcuts in main window. (#2263)
 - Minor: Added reconnect link to the "You are banned" message. (#2266)

src/common/ChannelChatters.cpp

@@ -64,9 +64,30 @@ void ChannelChatters::addPartedUser(const QString &user)
         });
     }
 }
+
 void ChannelChatters::setChatters(UsernameSet &&set)
 {
     *this->chatters_.access() = set;
 }
 
+const QColor ChannelChatters::getUserColor(const QString &user)
+{
+    const auto chatterColors = this->chatterColors_.access();
+
+    const auto search = chatterColors->find(user.toLower());
+    if (search == chatterColors->end())
+    {
+        // Returns an invalid color so we can decide not to override `textColor`
+        return QColor();
+    }
+
+    return search->second;
+}
+
+void ChannelChatters::setUserColor(const QString &user, const QColor &color)
+{
+    const auto chatterColors = this->chatterColors_.access();
+    chatterColors->insert_or_assign(user.toLower(), color);
+}
+
 }  // namespace chatterino

src/common/ChannelChatters.hpp

@@ -18,12 +18,15 @@ class ChannelChatters
     void addJoinedUser(const QString &user);
     void addPartedUser(const QString &user);
     void setChatters(UsernameSet &&set);
+    const QColor getUserColor(const QString &user);
+    void setUserColor(const QString &user, const QColor &color);
 
 private:
     Channel &channel_;
 
     // maps 2 char prefix to set of names
     UniqueAccess<UsernameSet> chatters_;
+    UniqueAccess<std::map<QString, QColor>> chatterColors_;
 
     // combines multiple joins/parts into one message
     UniqueAccess<QStringList> joinedUsers_;

src/providers/twitch/TwitchMessageBuilder.cpp

@@ -480,6 +480,16 @@ void TwitchMessageBuilder::addTextOrEmoji(const QString &string_)
         {
             QString username = match.captured(1);
 
+            if (getSettings()->colorUsernames)
+            {
+                if (auto userColor =
+                        this->twitchChannel->getUserColor(username);
+                    userColor.isValid())
+                {
+                    textColor = userColor;
+                }
+            }
+
             this->emplace<TextElement>(string, MessageElementFlag::BoldUsername,
                                        textColor, FontStyle::ChatMediumBold)
                 ->setLink({Link::UserInfo, username});
@@ -499,6 +509,16 @@ void TwitchMessageBuilder::addTextOrEmoji(const QString &string_)
 
         if (match.hasMatch() && chatters->contains(username))
         {
+            if (getSettings()->colorUsernames)
+            {
+                if (auto userColor =
+                        this->twitchChannel->getUserColor(username);
+                    userColor.isValid())
+                {
+                    textColor = userColor;
+                }
+            }
+
             this->emplace<TextElement>(string, MessageElementFlag::BoldUsername,
                                        textColor, FontStyle::ChatMediumBold)
                 ->setLink({Link::UserInfo, username});
@@ -580,6 +600,7 @@ void TwitchMessageBuilder::parseUsername()
     //    }
 
     this->message().loginName = this->userName;
+    this->twitchChannel->setUserColor(this->userName, this->usernameColor_);
 
     // Update current user color if this is our message
     auto currentUser = getApp()->accounts->twitch.getCurrent();

src/singletons/Settings.hpp

@@ -104,6 +104,7 @@ class Settings : public ABSettings, public ConcurrentSettings
     BoolSetting enableSmoothScrollingNewMessages = {
         "/appearance/smoothScrollingNewMessages", false};
     BoolSetting boldUsernames = {"/appearance/messages/boldUsernames", true};
+    BoolSetting colorUsernames = {"/appearance/messages/colorUsernames", true};
     BoolSetting findAllUsernames = {"/appearance/messages/findAllUsernames",
                                     false};
     // BoolSetting customizable splitheader

src/widgets/settingspages/GeneralPage.cpp

@@ -572,6 +572,7 @@ void GeneralPage::initLayout(GeneralPageView &layout)
                        s.autoCloseUserPopup);
     layout.addCheckbox("Lowercase domains (anti-phishing)", s.lowercaseDomains);
     layout.addCheckbox("Bold @usernames", s.boldUsernames);
+    layout.addCheckbox("Color @usernames", s.colorUsernames);
     layout.addCheckbox("Try to find usernames without @ prefix",
                        s.findAllUsernames);
     layout.addDropdown<float>(