UV/Image Editor: Overlay Popover

The overlay options in the image/uv editor is hidden in side panels and menus. Sometimes this panel is even hidden, while still useful.
The goal of this task is to introduce an overlay pop-over just like the overlay-popover of the 3d viewport.

Popover has
* UV Stretching (only available in the UV mode, when active object mode is a mesh and in OB_EDIT mode)
* Display As (only available in the UV mode, when active object mode is a mesh and in OB_EDIT mode)
* Show Modified (only available in the UV mode, when active object mode is a mesh and in OB_EDIT mode)
* Show UV Edges (including opacity slider; available UV, View, Paint, when active object mode is a mesh and in OB_EDIT mode)
* Udim tiles when no image is available.

Like the 3d viewport, there will be a editor toggle to enable/disable the overlays

For compatibility reasons the RNA properties are added to both the `SpaceImage.uv_editor` amd `SpaceImage.overlay`. On DNA level they are still stored in the SpaceImage. only new properties are added to the SpaceImageOverlay struct. During the next major release we could remove these options from `SpaceImage.uv_editor`. This should be noted in the Python section of release notes.

Reviewed By: Julian Eisel, Pablo Vazquez

Differential Revision: https://developer.blender.org/D8890

2 files changed, 37 insertions, 0 deletions

diff --git a/source/blender/makesrna/RNA_access.h b/source/blender/makesrna/RNA_access.h
index cfd87f14d48..1c2db53b12c 100644
--- a/source/blender/makesrna/RNA_access.h
+++ b/source/blender/makesrna/RNA_access.h
@@ -585,6 +585,7 @@ extern StructRNA RNA_SpaceDopeSheetEditor;
 extern StructRNA RNA_SpaceFileBrowser;
 extern StructRNA RNA_SpaceGraphEditor;
 extern StructRNA RNA_SpaceImageEditor;
+extern StructRNA RNA_SpaceImageOverlay;
 extern StructRNA RNA_SpaceInfo;
 extern StructRNA RNA_SpaceNLA;
 extern StructRNA RNA_SpaceNodeEditor;
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 0e5780012dd..2a4bc6bae06 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -1397,6 +1397,16 @@ static char *rna_View3DOverlay_path(PointerRNA *UNUSED(ptr))
 
 /* Space Image Editor */
 
+static PointerRNA rna_SpaceImage_overlay_get(PointerRNA *ptr)
+{
+  return rna_pointer_inherit_refine(ptr, &RNA_SpaceImageOverlay, ptr->data);
+}
+
+static char *rna_SpaceImageOverlay_path(PointerRNA *UNUSED(ptr))
+{
+  return BLI_strdup("overlay");
+}
+
 static char *rna_SpaceUVEditor_path(PointerRNA *UNUSED(ptr))
 {
   return BLI_strdup("uv_editor");
@@ -4512,6 +4522,23 @@ static void rna_def_space_properties(BlenderRNA *brna)
       prop, NC_SPACE | ND_SPACE_PROPERTIES, "rna_SpaceProperties_search_filter_update");
 }
 
+static void rna_def_space_image_overlay(BlenderRNA *brna)
+{
+  StructRNA *srna;
+  PropertyRNA *prop;
+
+  srna = RNA_def_struct(brna, "SpaceImageOverlay", NULL);
+  RNA_def_struct_sdna(srna, "SpaceImage");
+  RNA_def_struct_nested(brna, srna, "SpaceImageEditor");
+  RNA_def_struct_path_func(srna, "rna_SpaceImageOverlay_path");
+  RNA_def_struct_ui_text(
+      srna, "Overlay Settings", "Settings for display of overlays in the UV/Image editor");
+
+  prop = RNA_def_property(srna, "show_overlays", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "overlay.flag", SI_OVERLAY_SHOW_OVERLAYS);
+  RNA_def_property_ui_text(prop, "Show Overlays", "Display overlays like UV Maps and Metadata");
+}
+
 static void rna_def_space_image(BlenderRNA *brna)
 {
   StructRNA *srna;
@@ -4675,7 +4702,16 @@ static void rna_def_space_image(BlenderRNA *brna)
   RNA_def_property_clear_flag(prop, PROP_EDITABLE);
   RNA_def_property_ui_text(prop, "Show Mask Editor", "Show Mask editing related properties");
 
+  /* Overlays */
+  prop = RNA_def_property(srna, "overlay", PROP_POINTER, PROP_NONE);
+  RNA_def_property_flag(prop, PROP_NEVER_NULL);
+  RNA_def_property_struct_type(prop, "SpaceImageOverlay");
+  RNA_def_property_pointer_funcs(prop, "rna_SpaceImage_overlay_get", NULL, NULL, NULL);
+  RNA_def_property_ui_text(
+      prop, "Overlay Settings", "Settings for display of overlays in the UV/Image editor");
+
   rna_def_space_image_uv(brna);
+  rna_def_space_image_overlay(brna);
 
   /* mask */
   rna_def_space_mask_info(srna, NC_SPACE | ND_SPACE_IMAGE, "rna_SpaceImageEditor_mask_set");