Use scale factor from the window's list of entered outputs (sony#307)

Signed-off-by: Valentin Hăloiu <[email protected]>

Author: vially

src/flutter/shell/platform/linux_embedded/window/elinux_window_wayland.cc

@@ -148,6 +148,40 @@ const xdg_toplevel_listener ELinuxWindowWayland::kXdgToplevelListener = {
           self->running_ = false;
         }};
 
+const wl_surface_listener ELinuxWindowWayland::kWlSurfaceListener = {
+    .enter =
+        [](void* data, wl_surface* wl_surface, wl_output* output) {
+          // The compositor can send a null output: crbug.com/1332540
+          if (!output) {
+            ELINUX_LOG(ERROR) << "cannot enter a NULL output";
+            return;
+          }
+
+          const uint32_t output_id =
+              wl_proxy_get_id(reinterpret_cast<wl_proxy*>(output));
+          ELINUX_LOG(TRACE) << "window entered output " << output_id;
+          auto self = reinterpret_cast<ELinuxWindowWayland*>(data);
+
+          self->entered_outputs_.insert(output_id);
+          self->UpdateWindowScale();
+        },
+    .leave =
+        [](void* data, wl_surface* wl_surface, wl_output* output) {
+          // The compositor can send a null output: crbug.com/1332540
+          if (!output) {
+            ELINUX_LOG(ERROR) << "cannot leave a NULL output";
+            return;
+          }
+
+          const uint32_t output_id =
+              wl_proxy_get_id(reinterpret_cast<wl_proxy*>(output));
+          ELINUX_LOG(TRACE) << "window left output " << output_id;
+          auto self = reinterpret_cast<ELinuxWindowWayland*>(data);
+
+          self->entered_outputs_.erase(output_id);
+          self->UpdateWindowScale();
+        }};
+
 const wp_presentation_listener ELinuxWindowWayland::kWpPresentationListener = {
     .clock_id =
         [](void* data, wp_presentation* wp_presentation, uint32_t clk_id) {
@@ -570,9 +604,16 @@ const wl_output_listener ELinuxWindowWayland::kWlOutputListener = {
     .done = [](void* data, wl_output* wl_output) -> void {},
     .scale = [](void* data, wl_output* wl_output, int32_t scale) -> void {
       auto self = reinterpret_cast<ELinuxWindowWayland*>(data);
-      ELINUX_LOG(INFO) << "Display output scale: " << scale;
-      if (!self->view_properties_.force_scale_factor)
-        self->current_scale_ = scale;
+
+      const uint32_t output_id =
+          wl_proxy_get_id(reinterpret_cast<wl_proxy*>(wl_output));
+
+      ELINUX_LOG(INFO) << "Display scale for output(" << output_id
+                       << "): " << scale;
+
+      self->wl_output_scale_factors_[output_id] = scale;
+
+      self->UpdateWindowScale();
     },
 };
 
@@ -1125,6 +1166,8 @@ bool ELinuxWindowWayland::CreateRenderSurface(int32_t width, int32_t height) {
   native_window_ =
       std::make_unique<NativeWindowWayland>(wl_compositor_, width, height);
 
+  wl_surface_add_listener(native_window_->Surface(), &kWlSurfaceListener, this);
+
   xdg_surface_ =
       xdg_wm_base_get_xdg_surface(xdg_wm_base_, native_window_->Surface());
   if (!xdg_surface_) {
@@ -1527,4 +1570,31 @@ void ELinuxWindowWayland::DismissVirtualKeybaord() {
   }
 }
 
+void ELinuxWindowWayland::UpdateWindowScale() {
+  if (this->view_properties_.force_scale_factor)
+    return;
+
+  double scale_factor = 1.0;
+  for (auto output_id : entered_outputs_) {
+    if (wl_output_scale_factors_.find(output_id) ==
+        wl_output_scale_factors_.end())
+      continue;
+
+    auto output_scale_factor = wl_output_scale_factors_.at(output_id);
+    if (output_scale_factor > scale_factor)
+      scale_factor = output_scale_factor;
+  }
+
+  if (this->current_scale_ == scale_factor)
+    return;
+
+  ELINUX_LOG(TRACE) << "Window scale has changed: " << scale_factor;
+  this->current_scale_ = scale_factor;
+
+  if (this->binding_handler_delegate_) {
+    this->binding_handler_delegate_->OnWindowSizeChanged(
+        this->view_properties_.width, this->view_properties_.height);
+  }
+}
+
 }  // namespace flutter

src/flutter/shell/platform/linux_embedded/window/elinux_window_wayland.h

@@ -10,7 +10,7 @@
 
 #include <memory>
 #include <unordered_map>
-#include <vector>
+#include <unordered_set>
 
 #include "flutter/shell/platform/linux_embedded/surface/surface_gl.h"
 #include "flutter/shell/platform/linux_embedded/window/elinux_window.h"
@@ -102,10 +102,14 @@ class ELinuxWindowWayland : public ELinuxWindow, public WindowBindingHandler {
 
   void DismissVirtualKeybaord();
 
+  // Updates the surface scale of the window from the list of entered outputs.
+  void UpdateWindowScale();
+
   static const wl_registry_listener kWlRegistryListener;
   static const xdg_wm_base_listener kXdgWmBaseListener;
   static const xdg_surface_listener kXdgSurfaceListener;
   static const xdg_toplevel_listener kXdgToplevelListener;
+  static const wl_surface_listener kWlSurfaceListener;
   static const wl_seat_listener kWlSeatListener;
   static const wl_pointer_listener kWlPointerListener;
   static const wl_touch_listener kWlTouchListener;
@@ -181,6 +185,12 @@ class ELinuxWindowWayland : public ELinuxWindow, public WindowBindingHandler {
   // List of loaded Wayland cursor themes keyed by their (scaled) size.
   std::unordered_map<uint32_t, wl_cursor_theme*> wl_cursor_themes_;
 
+  // List of outputs that the window is currently rendered on.
+  std::unordered_set<uint32_t> entered_outputs_;
+
+  // List of output scale factors keyed by their ids.
+  std::unordered_map<uint32_t, int32_t> wl_output_scale_factors_;
+
   wl_data_device_manager* wl_data_device_manager_;
   wl_data_device* wl_data_device_;
   wl_data_offer* wl_data_offer_;