color-device: Derive color space from monitor calibration

This ignores the white point calibration for now because our color state
isn't expressive enough, yet.

Co-authored-by: Joan Torres <joan.torres@suse.com>
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3904>

src/backends/meta-color-device.c

@@ -623,19 +623,64 @@ on_manager_ready (MetaColorManager *color_manager,
   create_cd_device (color_device);
 }
 
+static ClutterColorspace
+get_color_space_from_monitor (MetaMonitor *monitor)
+{
+  switch (meta_monitor_get_color_space (monitor))
+    {
+    case META_OUTPUT_COLORSPACE_DEFAULT:
+    case META_OUTPUT_COLORSPACE_UNKNOWN:
+      return CLUTTER_COLORSPACE_DEFAULT;
+    case META_OUTPUT_COLORSPACE_BT2020:
+      return CLUTTER_COLORSPACE_BT2020;
+    }
+  g_assert_not_reached ();
+}
+
+static ClutterTransferFunction
+get_transfer_function_from_monitor (MetaMonitor *monitor)
+{
+  const MetaOutputHdrMetadata *hdr_metadata =
+    meta_monitor_get_hdr_metadata (monitor);
+
+  if (!hdr_metadata->active)
+    return CLUTTER_TRANSFER_FUNCTION_DEFAULT;
+
+  switch (hdr_metadata->eotf)
+    {
+    case META_OUTPUT_HDR_METADATA_EOTF_PQ:
+      return CLUTTER_TRANSFER_FUNCTION_PQ;
+    case META_OUTPUT_HDR_METADATA_EOTF_TRADITIONAL_GAMMA_SDR:
+      return CLUTTER_TRANSFER_FUNCTION_DEFAULT;
+    case META_OUTPUT_HDR_METADATA_EOTF_TRADITIONAL_GAMMA_HDR:
+      g_warning ("Unhandled HDR EOTF (traditional gamma hdr)");
+      return CLUTTER_TRANSFER_FUNCTION_DEFAULT;
+    case META_OUTPUT_HDR_METADATA_EOTF_HLG:
+      g_warning ("Unhandled HDR EOTF (HLG)");
+      return CLUTTER_TRANSFER_FUNCTION_DEFAULT;
+    }
+
+  g_assert_not_reached ();
+}
+
 static UpdateResult
 update_color_state (MetaColorDevice *color_device)
 {
+  MetaMonitor *monitor = color_device->monitor;
   MetaBackend *backend =
     meta_color_manager_get_backend (color_device->color_manager);
   ClutterContext *clutter_context = meta_backend_get_clutter_context (backend);
-  ClutterColorManager *clutter_color_manager =
+  g_autoptr (ClutterColorState) color_state = NULL;
-    clutter_context_get_color_manager (clutter_context);
+  ClutterColorspace colorspace;
-  ClutterColorState *color_state;
+  ClutterTransferFunction transfer_function;
   UpdateResult result = 0;
 
-  color_state =
+  colorspace = get_color_space_from_monitor (monitor);
-    clutter_color_manager_get_default_color_state (clutter_color_manager);
+  transfer_function = get_transfer_function_from_monitor (monitor);
+
+  color_state = clutter_color_state_new (clutter_context,
+                                         colorspace,
+                                         transfer_function);
 
   if (!color_device->color_state ||
       !clutter_color_state_equals (color_device->color_state, color_state))

src/backends/meta-monitor.c

@@ -2276,6 +2276,14 @@ meta_monitor_get_min_refresh_rate (MetaMonitor *monitor,
                                                 min_refresh_rate);
 }
 
+MetaOutputColorspace
+meta_monitor_get_color_space (MetaMonitor *monitor)
+{
+  MetaOutput *output = meta_monitor_get_main_output (monitor);
+
+  return meta_output_peek_color_space (output);
+}
+
 gboolean
 meta_monitor_set_color_space (MetaMonitor           *monitor,
                               MetaOutputColorspace   color_space,
@@ -2307,6 +2315,14 @@ meta_monitor_set_color_space (MetaMonitor           *monitor,
   return TRUE;
 }
 
+MetaOutputHdrMetadata *
+meta_monitor_get_hdr_metadata (MetaMonitor *monitor)
+{
+  MetaOutput *output = meta_monitor_get_main_output (monitor);
+
+  return meta_output_peek_hdr_metadata (output);
+}
+
 gboolean
 meta_monitor_set_hdr_metadata (MetaMonitor            *monitor,
                                MetaOutputHdrMetadata  *metadata,

src/backends/meta-monitor.h

@@ -312,10 +312,14 @@ size_t meta_monitor_get_gamma_lut_size (MetaMonitor *monitor);
 void meta_monitor_set_gamma_lut (MetaMonitor        *monitor,
                                  const MetaGammaLut *lut);
 
+MetaOutputColorspace meta_monitor_get_color_space (MetaMonitor *monitor);
+
 gboolean meta_monitor_set_color_space (MetaMonitor           *monitor,
                                        MetaOutputColorspace   color_space,
                                        GError               **error);
 
+MetaOutputHdrMetadata * meta_monitor_get_hdr_metadata (MetaMonitor *monitor);
+
 gboolean meta_monitor_set_hdr_metadata (MetaMonitor            *monitor,
                                         MetaOutputHdrMetadata  *metadata,
                                         GError                **error);