logical-monitor: Make scale a float

To support fractional scaling, the logical monitor scale must be stored
as a float. No other functional changes is part of this commit.

https://bugzilla.gnome.org/show_bug.cgi?id=765011

src/backends/meta-logical-monitor.c

@@ -107,7 +107,7 @@ MetaLogicalMonitor *
 meta_logical_monitor_new_derived (MetaMonitorManager *monitor_manager,
                                   MetaMonitor        *monitor,
                                   MetaRectangle      *layout,
-                                  int                 scale,
+                                  float               scale,
                                   int                 monitor_number)
 {
   MetaLogicalMonitor *logical_monitor;
@@ -175,7 +175,7 @@ meta_logical_monitor_make_primary (MetaLogicalMonitor *logical_monitor)
   logical_monitor->is_primary = TRUE;
 }
 
-int
+float
 meta_logical_monitor_get_scale (MetaLogicalMonitor *logical_monitor)
 {
   return logical_monitor->scale;

src/backends/meta-logical-monitor.h

@@ -40,7 +40,7 @@ struct _MetaLogicalMonitor
   gboolean is_primary;
   gboolean is_presentation; /* XXX: not yet used */
   gboolean in_fullscreen;
-  int scale;
+  float scale;
   MetaMonitorTransform transform;
 
   /* The primary or first output for this monitor, 0 if we can't figure out.
@@ -68,7 +68,7 @@ MetaLogicalMonitor * meta_logical_monitor_new (MetaMonitorManager       *monitor
 MetaLogicalMonitor * meta_logical_monitor_new_derived (MetaMonitorManager *monitor_manager,
                                                        MetaMonitor        *monitor,
                                                        MetaRectangle      *layout,
-                                                       int                 scale,
+                                                       float               scale,
                                                        int                 monitor_number);
 
 void meta_logical_monitor_add_monitor (MetaLogicalMonitor *logical_monitor,
@@ -78,7 +78,7 @@ gboolean meta_logical_monitor_is_primary (MetaLogicalMonitor *logical_monitor);
 
 void meta_logical_monitor_make_primary (MetaLogicalMonitor *logical_monitor);
 
-int meta_logical_monitor_get_scale (MetaLogicalMonitor *logical_monitor);
+float meta_logical_monitor_get_scale (MetaLogicalMonitor *logical_monitor);
 
 GList * meta_logical_monitor_get_monitors (MetaLogicalMonitor *logical_monitor);
 

src/backends/meta-monitor-config-manager.c

@@ -488,7 +488,7 @@ create_preferred_logical_monitor_config (MetaMonitorManager          *monitor_ma
 {
   MetaMonitorMode *mode;
   int width, height;
-  int scale;
+  float scale;
   MetaMonitorConfig *monitor_config;
   MetaLogicalMonitorConfig *logical_monitor_config;
 
@@ -949,10 +949,10 @@ meta_verify_logical_monitor_config (MetaLogicalMonitorConfig    *logical_monitor
   int expected_mode_width = 0;
   int expected_mode_height = 0;
 
-  if (logical_monitor_config->scale < 1)
+  if (logical_monitor_config->scale < 1.0)
     {
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
-                   "Invalid logical monitor config scale %d",
+                   "Invalid logical monitor config scale %g",
                    logical_monitor_config->scale);
       return FALSE;
     }

src/backends/meta-monitor-config-manager.h

@@ -41,7 +41,7 @@ typedef struct _MetaLogicalMonitorConfig
   MetaRectangle layout;
   GList *monitor_configs;
   MetaMonitorTransform transform;
-  int scale;
+  float scale;
   gboolean is_primary;
   gboolean is_presentation;
 } MetaLogicalMonitorConfig;

src/backends/meta-monitor-config-store.c

@@ -828,14 +828,14 @@ handle_text (GMarkupParseContext *context,
 
     case STATE_LOGICAL_MONITOR_SCALE:
       {
-        if (!read_int (text, text_len,
-                       &parser->current_logical_monitor_config->scale, error))
+        if (!read_float (text, text_len,
+                         &parser->current_logical_monitor_config->scale, error))
           return;
 
-        if (parser->current_logical_monitor_config->scale <= 0)
+        if (parser->current_logical_monitor_config->scale < 1.0)
           {
             g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
-                         "Logical monitor scale '%d' invalid",
+                         "Logical monitor scale '%g' invalid",
                          parser->current_logical_monitor_config->scale);
             return;
           }
@@ -1074,7 +1074,7 @@ append_logical_monitor_xml (GString                  *buffer,
                           logical_monitor_config->layout.x);
   g_string_append_printf (buffer, "      <y>%d</y>\n",
                           logical_monitor_config->layout.y);
-  g_string_append_printf (buffer, "      <scale>%d</scale>\n",
+  g_string_append_printf (buffer, "      <scale>%g</scale>\n",
                           logical_monitor_config->scale);
   if (logical_monitor_config->is_primary)
     g_string_append (buffer, "      <primary>yes</primary>\n");

src/backends/meta-monitor-manager-dummy.c

@@ -59,7 +59,7 @@ struct _MetaMonitorManagerDummyClass
 
 typedef struct _MetaOutputDummy
 {
-  int scale;
+  float scale;
 } MetaOutputDummy;
 
 G_DEFINE_TYPE (MetaMonitorManagerDummy, meta_monitor_manager_dummy, META_TYPE_MONITOR_MANAGER);
@@ -74,7 +74,7 @@ static void
 append_monitor (GArray *modes,
                 GArray *crtcs,
                 GArray *outputs,
-                int     scale)
+                float   scale)
 {
   MetaCrtcMode modes_decl[] = {
     {
@@ -242,11 +242,25 @@ meta_output_dummy_notify_destroy (MetaOutput *output)
   g_clear_pointer (&output->driver_private, g_free);
 }
 
+static gboolean
+is_scale_supported (float scale)
+{
+  unsigned int i;
+
+  for (i = 0; i < G_N_ELEMENTS (supported_scales_dummy); i++)
+    {
+      if (scale == supported_scales_dummy[i])
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
 static void
 meta_monitor_manager_dummy_read_current (MetaMonitorManager *manager)
 {
   unsigned int num_monitors = 1;
-  int *monitor_scales = NULL;
+  float *monitor_scales = NULL;
   const char *num_monitors_str;
   const char *monitor_scales_str;
   const char *tiled_monitors_str;
@@ -298,9 +312,9 @@ meta_monitor_manager_dummy_read_current (MetaMonitorManager *manager)
         }
     }
 
-  monitor_scales = g_newa (int, num_monitors);
+  monitor_scales = g_newa (typeof (*monitor_scales), num_monitors);
   for (i = 0; i < num_monitors; i++)
-    monitor_scales[i] = 1;
+    monitor_scales[i] = 1.0;
 
   monitor_scales_str = getenv ("MUTTER_DEBUG_DUMMY_MONITOR_SCALES");
   if (monitor_scales_str)
@@ -313,11 +327,11 @@ meta_monitor_manager_dummy_read_current (MetaMonitorManager *manager)
                       "of monitors (defaults to 1).\n");
       for (i = 0; i < num_monitors && scales_str_list[i]; i++)
         {
-          int scale = g_ascii_strtoll (scales_str_list[i], NULL, 10);
-          if (scale == 1 || scale == 2)
+          float scale = g_ascii_strtod (scales_str_list[i], NULL);
+          if (is_scale_supported (scale))
             monitor_scales[i] = scale;
           else
-            meta_warning ("Invalid dummy monitor scale");
+            meta_warning ("Invalid dummy monitor scale\n");
         }
       g_strfreev (scales_str_list);
     }
@@ -592,7 +606,7 @@ meta_monitor_manager_dummy_is_transform_handled (MetaMonitorManager  *manager,
   return manager_dummy->is_transform_handled;
 }
 
-static int
+static float
 meta_monitor_manager_dummy_calculate_monitor_mode_scale (MetaMonitorManager *manager,
                                                          MetaMonitor        *monitor,
                                                          MetaMonitorMode    *monitor_mode)

src/backends/meta-monitor-manager-private.h

@@ -390,9 +390,9 @@ struct _MetaMonitorManagerClass
                                     MetaCrtc            *,
                                     MetaMonitorTransform);
 
-  int (*calculate_monitor_mode_scale) (MetaMonitorManager *,
-                                       MetaMonitor        *,
-                                       MetaMonitorMode    *);
+  float (*calculate_monitor_mode_scale) (MetaMonitorManager *,
+                                         MetaMonitor        *,
+                                         MetaMonitorMode    *);
 
   void (*get_supported_scales) (MetaMonitorManager *,
                                 float             **,
@@ -504,7 +504,7 @@ void               meta_monitor_manager_lid_is_closed_changed (MetaMonitorManage
 
 gboolean           meta_monitor_manager_is_headless (MetaMonitorManager *manager);
 
-int                meta_monitor_manager_calculate_monitor_mode_scale (MetaMonitorManager *manager,
+float              meta_monitor_manager_calculate_monitor_mode_scale (MetaMonitorManager *manager,
                                                                       MetaMonitor        *monitor,
                                                                       MetaMonitorMode    *monitor_mode);
 

src/backends/meta-monitor-manager.c

@@ -184,7 +184,7 @@ derive_monitor_layout (MetaMonitor   *monitor,
   meta_monitor_derive_dimensions (monitor, &layout->width, &layout->height);
 }
 
-static int
+static float
 derive_configured_global_scale (MetaMonitorManager *manager)
 {
   MetaMonitorsConfig *config;
@@ -192,14 +192,14 @@ derive_configured_global_scale (MetaMonitorManager *manager)
 
   config = meta_monitor_config_manager_get_current (manager->config_manager);
   if (!config)
-    return 1;
+    return 1.0;
 
   logical_monitor_config = config->logical_monitor_configs->data;
 
   return logical_monitor_config->scale;
 }
 
-static int
+static float
 calculate_monitor_scale (MetaMonitorManager *manager,
                          MetaMonitor        *monitor)
 {
@@ -211,19 +211,19 @@ calculate_monitor_scale (MetaMonitorManager *manager,
                                                             monitor_mode);
 }
 
-static int
+static float
 derive_calculated_global_scale (MetaMonitorManager *manager)
 {
   MetaMonitor *primary_monitor;
 
   primary_monitor = meta_monitor_manager_get_primary_monitor (manager);
   if (!primary_monitor)
-    return 1;
+    return 1.0;
 
   return calculate_monitor_scale (manager, primary_monitor);
 }
 
-static int
+static float
 derive_scale_from_config (MetaMonitorManager *manager,
                           MetaRectangle      *layout)
 {
@@ -240,7 +240,7 @@ derive_scale_from_config (MetaMonitorManager *manager,
     }
 
   g_warning ("Missing logical monitor, using scale 1");
-  return 1;
+  return 1.0;
 }
 
 static void
@@ -253,7 +253,7 @@ meta_monitor_manager_rebuild_logical_monitors_derived (MetaMonitorManager
   MetaLogicalMonitor *primary_logical_monitor = NULL;
   gboolean use_configured_scale;
   gboolean use_global_scale;
-  int global_scale = 0;
+  float global_scale = 0.0;
   MetaMonitorManagerCapability capabilities;
 
   monitor_number = 0;
@@ -291,7 +291,7 @@ meta_monitor_manager_rebuild_logical_monitors_derived (MetaMonitorManager
         }
       else
         {
-          int scale;
+          float scale;
 
           if (use_global_scale)
             scale = global_scale;
@@ -393,7 +393,7 @@ meta_monitor_manager_is_headless (MetaMonitorManager *manager)
   return !manager->monitors;
 }
 
-int
+float
 meta_monitor_manager_calculate_monitor_mode_scale (MetaMonitorManager *manager,
                                                    MetaMonitor        *monitor,
                                                    MetaMonitorMode    *monitor_mode)
@@ -1894,6 +1894,14 @@ derive_logical_monitor_size (GList                       *monitor_configs,
   switch (layout_mode)
     {
     case META_LOGICAL_MONITOR_LAYOUT_MODE_LOGICAL:
+      if (fmodf (width, scale) != 0.0 || fmodf (height, scale) != 0.0)
+        {
+          g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                       "Scale %g not valid for resolution %dx%d",
+                       scale, width, height);
+          return FALSE;
+        }
+
       width /= scale;
       height /= scale;
       break;
@@ -1967,7 +1975,7 @@ create_logical_monitor_config_from_variant (MetaMonitorManager          *manager
       .height = height
     },
     .transform = transform,
-    .scale = (int) scale,
+    .scale = scale,
     .is_primary = is_primary,
     .monitor_configs = monitor_configs
   };

src/backends/meta-monitor.c

@@ -1261,7 +1261,7 @@ meta_monitor_calculate_crtc_pos (MetaMonitor         *monitor,
 /* From http://en.wikipedia.org/wiki/4K_resolution#Resolutions_of_common_formats */
 #define SMALLEST_4K_WIDTH 3656
 
-static int
+static float
 calculate_scale (MetaMonitor     *monitor,
                  MetaMonitorMode *monitor_mode)
 {
@@ -1269,7 +1269,7 @@ calculate_scale (MetaMonitor     *monitor,
   int width_mm, height_mm;
   int scale;
 
-  scale = 1;
+  scale = 1.0;
 
   meta_monitor_mode_get_resolution (monitor_mode,
                                     &resolution_width,
@@ -1314,14 +1314,14 @@ calculate_scale (MetaMonitor     *monitor,
        * pick higher ratio than 2 automatically.
        */
       if (dpi_x > HIDPI_LIMIT && dpi_y > HIDPI_LIMIT)
-        scale = 2;
+        scale = 2.0;
     }
 
 out:
   return scale;
 }
 
-int
+float
 meta_monitor_calculate_mode_scale (MetaMonitor     *monitor,
                                    MetaMonitorMode *monitor_mode)
 {

src/backends/meta-monitor.h

@@ -160,8 +160,8 @@ void meta_monitor_calculate_crtc_pos (MetaMonitor         *monitor,
                                       int                 *out_x,
                                       int                 *out_y);
 
-int meta_monitor_calculate_mode_scale (MetaMonitor     *monitor,
-                                       MetaMonitorMode *monitor_mode);
+float meta_monitor_calculate_mode_scale (MetaMonitor     *monitor,
+                                         MetaMonitorMode *monitor_mode);
 
 MetaMonitorModeSpec * meta_monitor_mode_get_spec (MetaMonitorMode *monitor_mode);
 

src/backends/meta-settings.c

@@ -69,7 +69,7 @@ calculate_ui_scaling_factor (MetaSettings *settings)
     meta_backend_get_monitor_manager (settings->backend);
   GList *logical_monitors;
   GList *l;
-  int max_scale = 1;
+  float max_scale = 1.0;
 
   logical_monitors =
     meta_monitor_manager_get_logical_monitors (monitor_manager);
@@ -81,7 +81,9 @@ calculate_ui_scaling_factor (MetaSettings *settings)
                        max_scale);
     }
 
-  return max_scale;
+  g_warn_if_fail (fmodf (max_scale, 1.0) == 0.0);
+
+  return (int) max_scale;
 }
 
 static int

src/backends/native/meta-cursor-renderer-native.c

@@ -239,13 +239,13 @@ update_monitor_crtc_cursor (MetaMonitor         *monitor,
   MetaCursorRendererNativePrivate *priv =
     meta_cursor_renderer_native_get_instance_private (cursor_renderer_native);
   MetaRectangle scaled_crtc_rect;
-  int scale;
+  float scale;
   int crtc_x, crtc_y;
 
   if (meta_is_stage_views_scaled ())
     scale = meta_logical_monitor_get_scale (data->in_logical_monitor);
   else
-    scale = 1;
+    scale = 1.0;
 
   meta_monitor_calculate_crtc_pos (monitor, monitor_mode,
                                    monitor_crtc_mode->output,

src/backends/native/meta-monitor-manager-kms.c

@@ -1838,7 +1838,7 @@ meta_monitor_manager_kms_is_transform_handled (MetaMonitorManager  *manager,
     return FALSE;
 }
 
-static int
+static float
 meta_monitor_manager_kms_calculate_monitor_mode_scale (MetaMonitorManager *manager,
                                                        MetaMonitor        *monitor,
                                                        MetaMonitorMode    *monitor_mode)

src/backends/native/meta-renderer-native.c

@@ -1707,7 +1707,7 @@ meta_renderer_native_create_view (MetaRenderer       *renderer,
   MetaMonitorTransform view_transform;
   CoglOnscreen *onscreen = NULL;
   CoglOffscreen *offscreen = NULL;
-  int scale;
+  float scale;
   int width, height;
   MetaRendererView *view;
   GError *error = NULL;
@@ -1715,9 +1715,9 @@ meta_renderer_native_create_view (MetaRenderer       *renderer,
   view_transform = calculate_view_transform (monitor_manager, logical_monitor);
 
   if (meta_is_stage_views_scaled ())
-    scale = logical_monitor->scale;
+    scale = meta_logical_monitor_get_scale (logical_monitor);
   else
-    scale = 1;
+    scale = 1.0;
 
   width = logical_monitor->rect.width * scale;
   height = logical_monitor->rect.height * scale;
@@ -1743,7 +1743,7 @@ meta_renderer_native_create_view (MetaRenderer       *renderer,
 
   view = g_object_new (META_TYPE_RENDERER_VIEW,
                        "layout", &logical_monitor->rect,
-                       "scale", (float) scale,
+                       "scale", scale,
                        "framebuffer", onscreen,
                        "offscreen", offscreen,
                        "logical-monitor", logical_monitor,

src/backends/x11/meta-monitor-manager-xrandr.c

@@ -1791,7 +1791,7 @@ meta_monitor_manager_xrandr_is_transform_handled (MetaMonitorManager  *manager,
   return TRUE;
 }
 
-static int
+static float
 meta_monitor_manager_xrandr_calculate_monitor_mode_scale (MetaMonitorManager *manager,
                                                           MetaMonitor        *monitor,
                                                           MetaMonitorMode    *monitor_mode)

src/backends/x11/nested/meta-renderer-x11-nested.c

@@ -173,7 +173,7 @@ meta_renderer_x11_nested_create_view (MetaRenderer       *renderer,
   ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
   CoglContext *cogl_context = clutter_backend_get_cogl_context (clutter_backend);
   MetaMonitorTransform view_transform;
-  int view_scale;
+  float view_scale;
   int width, height;
   CoglOffscreen *fake_onscreen;
   CoglOffscreen *offscreen;
@@ -183,7 +183,7 @@ meta_renderer_x11_nested_create_view (MetaRenderer       *renderer,
   if (meta_is_stage_views_scaled ())
     view_scale = logical_monitor->scale;
   else
-    view_scale = 1;
+    view_scale = 1.0;
 
   if (meta_monitor_transform_is_rotated (view_transform))
     {
@@ -210,7 +210,7 @@ meta_renderer_x11_nested_create_view (MetaRenderer       *renderer,
                        "framebuffer", COGL_FRAMEBUFFER (fake_onscreen),
                        "offscreen", COGL_FRAMEBUFFER (offscreen),
                        "transform", view_transform,
-                       "scale", (float) view_scale,
+                       "scale", view_scale,
                        "logical-monitor", logical_monitor,
                        NULL);
 }

src/tests/meta-monitor-manager-test.c

@@ -400,7 +400,7 @@ meta_monitor_manager_test_is_transform_handled (MetaMonitorManager  *manager,
   return manager_test->handles_transforms;
 }
 
-static int
+static float
 meta_monitor_manager_test_calculate_monitor_mode_scale (MetaMonitorManager *manager,
                                                         MetaMonitor        *monitor,
                                                         MetaMonitorMode    *monitor_mode)

src/tests/meta-monitor-manager-test.h

@@ -34,7 +34,7 @@ typedef struct _MetaMonitorTestSetup
 
 typedef struct _MetaOutputTest
 {
-  int scale;
+  float scale;
 } MetaOutputTest;
 
 #define META_TYPE_MONITOR_MANAGER_TEST (meta_monitor_manager_test_get_type ())

src/wayland/meta-wayland-outputs.c

@@ -205,7 +205,7 @@ send_output_events (struct wl_resource *resource,
     {
       int scale;
 
-      scale = meta_logical_monitor_get_scale (logical_monitor);
+      scale = (int) meta_logical_monitor_get_scale (logical_monitor);
       if (need_all_events ||
           old_scale != scale)
         {
@@ -273,7 +273,7 @@ meta_wayland_output_set_logical_monitor (MetaWaylandOutput  *wayland_output,
 
   if (current_mode == preferred_mode)
     wayland_output->mode_flags |= WL_OUTPUT_MODE_PREFERRED;
-  wayland_output->scale = meta_logical_monitor_get_scale (logical_monitor);
+  wayland_output->scale = (int) meta_logical_monitor_get_scale (logical_monitor);
   wayland_output->refresh_rate = meta_monitor_mode_get_refresh_rate (current_mode);
 }
 

src/wayland/meta-wayland-surface-role-cursor.c

@@ -104,7 +104,7 @@ cursor_sprite_prepare_at (MetaCursorSprite             *cursor_sprite,
       MetaBackend *backend = meta_get_backend ();
       MetaMonitorManager *monitor_manager =
         meta_backend_get_monitor_manager (backend);
-      const MetaLogicalMonitor *logical_monitor;
+      MetaLogicalMonitor *logical_monitor;
 
       logical_monitor =
         meta_monitor_manager_get_logical_monitor_at (monitor_manager, x, y);
@@ -115,7 +115,8 @@ cursor_sprite_prepare_at (MetaCursorSprite             *cursor_sprite,
           if (meta_is_stage_views_scaled ())
             texture_scale = 1.0 / surface->scale;
           else
-            texture_scale = (float) logical_monitor->scale / surface->scale;
+            texture_scale = (meta_logical_monitor_get_scale (logical_monitor) /
+                             surface->scale);
 
           meta_cursor_sprite_set_texture_scale (cursor_sprite, texture_scale);
         }

src/wayland/meta-window-wayland.c

@@ -70,7 +70,7 @@ get_window_geometry_scale_for_logical_monitor (MetaLogicalMonitor *logical_monit
   if (meta_is_stage_views_scaled ())
     return 1;
   else
-    return logical_monitor->scale;
+    return meta_logical_monitor_get_scale (logical_monitor);
 }
 
 static void
@@ -359,6 +359,7 @@ meta_window_wayland_update_main_monitor (MetaWindow *window)
   MetaLogicalMonitor *from;
   MetaLogicalMonitor *to;
   MetaLogicalMonitor *scaled_new;
+  float from_scale, to_scale;
   float scale;
   MetaRectangle rect;
 
@@ -383,9 +384,12 @@ meta_window_wayland_update_main_monitor (MetaWindow *window)
   if (from == to)
     return;
 
+  from_scale = meta_logical_monitor_get_scale (from);
+  to_scale = meta_logical_monitor_get_scale (to);
+
   /* If we are setting the first output, unsetting the output, or the new has
    * the same scale as the old no need to do any further checking. */
-  if (from == NULL || to == NULL || from->scale == to->scale)
+  if (from == NULL || to == NULL || from_scale == to_scale)
     {
       window->monitor = to;
       return;
@@ -400,7 +404,7 @@ meta_window_wayland_update_main_monitor (MetaWindow *window)
   /* To avoid a window alternating between two main monitors because scaling
    * changes the main monitor, wait until both the current and the new scale
    * will result in the same main monitor. */
-  scale = (float)to->scale / from->scale;
+  scale = to_scale / from_scale;
   rect = window->rect;
   scale_rect_size (&rect, scale);
   scaled_new =