internal: add a new monitor auto system

src/Compositor.cpp

@@ -2485,3 +2485,37 @@ void CCompositor::setIdleActivityInhibit(bool enabled) {
     wlr_idle_set_enabled(g_pCompositor->m_sWLRIdle, g_pCompositor->m_sSeat.seat, enabled);
     wlr_idle_notifier_v1_set_inhibited(g_pCompositor->m_sWLRIdleNotifier, !enabled);
 }
+
+void CCompositor::arrangeMonitors() {
+    std::vector<CMonitor*> toArrange;
+    std::vector<CMonitor*> arranged;
+
+    for (auto& m : m_vMonitors)
+        toArrange.push_back(m.get());
+
+    for (auto it = toArrange.begin(); it != toArrange.end(); ++it) {
+        auto m = *it;
+
+        if (m->activeMonitorRule.offset > Vector2D{-1, -1}) {
+            // explicit.
+            m->moveTo(m->activeMonitorRule.offset);
+            arranged.push_back(m);
+            it = toArrange.erase(it);
+
+            if (it == toArrange.end())
+                break;
+        }
+    }
+
+    // auto left
+    int maxOffset = 0;
+    for (auto& m : arranged) {
+        if (m->vecPosition.x + m->vecSize.x > maxOffset)
+            maxOffset = m->vecPosition.x + m->vecSize.x;
+    }
+
+    for (auto& m : toArrange) {
+        m->moveTo({maxOffset, 0});
+        maxOffset += m->vecPosition.x;
+    }
+}

src/Compositor.hpp

@@ -202,6 +202,7 @@ class CCompositor {
     CWindow*       getForceFocus();
     void           notifyIdleActivity();
     void           setIdleActivityInhibit(bool inhibit);
+    void           arrangeMonitors();
 
     std::string    explicitConfigPath;
 

src/helpers/Monitor.cpp

@@ -489,6 +489,8 @@ void CMonitor::setMirror(const std::string& mirrorOf) {
         // remove from mvmonitors
         std::erase_if(g_pCompositor->m_vMonitors, [&](const auto& other) { return other.get() == this; });
 
+        g_pCompositor->arrangeMonitors();
+
         g_pCompositor->setActiveMonitor(g_pCompositor->m_vMonitors.front().get());
 
         g_pCompositor->sanityCheckWorkspaces();
@@ -622,3 +624,10 @@ void CMonitor::setSpecialWorkspace(CWorkspace* const pWorkspace) {
 void CMonitor::setSpecialWorkspace(const int& id) {
     setSpecialWorkspace(g_pCompositor->getWorkspaceByID(id));
 }
+
+void CMonitor::moveTo(const Vector2D& pos) {
+    vecPosition = pos;
+
+    if (!isMirror())
+        wlr_output_layout_add(g_pCompositor->m_sWLROutputLayout, output, (int)vecPosition.x, (int)vecPosition.y);
+}

src/helpers/Monitor.hpp

@@ -109,6 +109,7 @@ class CMonitor {
     void                       changeWorkspace(const int& id, bool internal = false);
     void                       setSpecialWorkspace(CWorkspace* const pWorkspace);
     void                       setSpecialWorkspace(const int& id);
+    void                       moveTo(const Vector2D& pos);
 
     std::shared_ptr<CMonitor>* m_pThisWrap            = nullptr;
     bool                       m_bEnabled             = false;

src/helpers/Vector2D.hpp

@@ -43,6 +43,14 @@ class Vector2D {
         return Vector2D(this->x / a.x, this->y / a.y);
     }
 
+    bool operator>(const Vector2D& a) const {
+        return this->x > a.x && this->y > a.y;
+    }
+
+    bool operator<(const Vector2D& a) const {
+        return this->x < a.x && this->y < a.y;
+    }
+
     double   distance(const Vector2D& other) const;
 
     Vector2D clamp(const Vector2D& min, const Vector2D& max = Vector2D()) const;

src/render/Renderer.cpp

@@ -1903,8 +1903,7 @@ bool CHyprRenderer::applyMonitorRule(CMonitor* pMonitor, SMonitorRule* pMonitorR
     g_pHyprOpenGL->destroyMonitorResources(pMonitor);
 
     // updato wlroots
-    if (!pMonitor->isMirror())
-        wlr_output_layout_add(g_pCompositor->m_sWLROutputLayout, pMonitor->output, (int)pMonitor->vecPosition.x, (int)pMonitor->vecPosition.y);
+    g_pCompositor->arrangeMonitors();
 
     wlr_damage_ring_set_bounds(&pMonitor->damage, pMonitor->vecTransformedSize.x, pMonitor->vecTransformedSize.y);