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

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/draw/engines/overlay/overlay_private.h b/source/blender/draw/engines/overlay/overlay_private.h
index ada2c2c8d1f..ef7a2db476c 100644
--- a/source/blender/draw/engines/overlay/overlay_private.h
+++ b/source/blender/draw/engines/overlay/overlay_private.h
@@ -356,6 +356,7 @@ typedef struct OVERLAY_PrivateData {
     bool do_uv_shadow_overlay;
     bool do_uv_stretching_overlay;
     bool do_tiled_image_overlay;
+    bool do_tiled_image_border_overlay;
 
     bool do_faces;
     bool do_face_dots;