wp-fractional-scaling-v1 impl (#1373)

* Initial fractional scaling impl

* apply UV after geom calcs

* fix scaling -> scale

* meson: add fractional scale proto

Co-authored-by: Mihai Fufezan <fufexan@protonmail.com>

src/protocols/FractionalScale.hpp

@@ -0,0 +1,38 @@
+#pragma once
+
+#include "../defines.hpp"
+#include "fractional-scale-v1-protocol.h"
+
+#include <vector>
+#include <algorithm>
+
+struct SFractionalScaleAddon {
+    wlr_surface* pSurface       = nullptr;
+    double       preferredScale = 1.0;
+    wl_resource* pResource      = nullptr;
+};
+
+class CFractionalScaleProtocolManager {
+  public:
+    CFractionalScaleProtocolManager();
+
+    void bindManager(wl_client* client, void* data, uint32_t version, uint32_t id);
+
+    void displayDestroy();
+
+    void setPreferredScaleForSurface(wlr_surface*, double);
+
+    void removeAddon(wlr_surface*);
+
+    // handlers
+
+    void getFractionalScale(wl_client* client, wl_resource* resource, uint32_t id, wl_resource* surface);
+
+  private:
+    SFractionalScaleAddon*                              getAddonForSurface(wlr_surface*);
+
+    std::vector<std::unique_ptr<SFractionalScaleAddon>> m_vFractionalScaleAddons;
+
+    wl_global*                                          m_pGlobal = nullptr;
+    wl_listener                                         m_liDisplayDestroy;
+};