frontend_wayland/WpViewporter: Better name for dirty()

We change this to `changed_since_last_resolve()`.

src/server/frontend_wayland/wl_surface.cpp

@@ -345,11 +345,11 @@ void mf::WlSurface::commit(WlSurfaceState const& state)
     }
 
     bool needs_buffer_submission =
-        state.scale ||                          // If the scale has changed, or...
-        state.viewport ||                       // ...we've added a viewport, or...
-        (viewport && viewport.value().dirty()); // ...the viewport has changed...
-                                                // ...then we'll need to submit a new frame, even if the client hasn't
-                                                // attached a new buffer.
+        state.scale ||                                               // If the scale has changed, or...
+        state.viewport ||                                            // ...we've added a viewport, or...
+        (viewport && viewport.value().changed_since_last_resolve()); // ...the viewport has changed...
+                                                                     // ...then we'll need to submit a new frame, even if the client hasn't
+                                                                     // attached a new buffer.
 
     auto const executor_send_frame_callbacks = [executor = wayland_executor, weak_self = mw::make_weak(this)]()
         {

src/server/frontend_wayland/wp_viewporter.cpp

@@ -77,9 +77,9 @@ mf::Viewport::~Viewport()
 {
 }
 
-auto mf::Viewport::dirty() -> bool
+auto mf::Viewport::changed_since_last_resolve() -> bool
 {
-    return std::exchange(dirty_, false);
+    return viewport_changed;
 }
 
 namespace
@@ -165,6 +165,7 @@ auto mf::Viewport::resolve_viewport(int32_t scale, geom::Size buffer_size) const
             }
         }();
 
+    viewport_changed = false;
     return std::make_pair(src_bounds, logical_size);
 }
 
@@ -200,7 +201,7 @@ void mf::Viewport::set_source(double x, double y, double width, double height)
     {
         source = geometry::RectangleD{{x, y}, {width, height}};
     }
-    dirty_ = true;
+    viewport_changed = true;
 }
 
 void mf::Viewport::set_destination(int32_t width, int32_t height)
@@ -233,5 +234,5 @@ void mf::Viewport::set_destination(int32_t width, int32_t height)
         destination = geometry::Size{width, height};
     }
 
-    dirty_ = true;
+    viewport_changed = true;
 }

src/server/frontend_wayland/wp_viewporter.h

@@ -51,9 +51,9 @@ class Viewport : public wayland::Viewport
     ~Viewport() override;
 
     /**
-     * Have the source or destination values changed since the last call to dirty()?
+     * Have the source or destination values changed since the last `resolve_viewport`?
      */
-    auto dirty() -> bool;
+    auto changed_since_last_resolve() -> bool;
 
     /**
      * Combine the viewport parameters with submitted buffer and scale to produce final parameters
@@ -68,7 +68,7 @@ class Viewport : public wayland::Viewport
     void set_source(double x, double y, double width, double height) override;
     void set_destination(int32_t width, int32_t height) override;
 
-    bool dirty_;
+    bool mutable viewport_changed;
     wayland::Weak<wayland::Surface> surface;
     std::optional<geometry::RectangleD> source;
     std::optional<geometry::Size> destination;