UV Editor: Grid and snapping improvements

Implements T89789, T89792, custom grid (described as dynamic grid in
T78389) and UV grid snapping (T78391)
Replaces the default UV editor grid with 2 new types of grid :

* Custom grid: Allows the user to create an NxN grid, where the value
  of N is specified by the user.
* Subdividing grid: Subdivides the UV editor grid when the user
  zooms in the viewport and vice versa when zooming out.

UV snapping improvements :
* Increment snapping: Increment values for snapping are calculated based
  on which grid type is being used in the UV editor
  (subdividing or custom). In general the increment value is equal to
  the distance between 2 visible grid lines.
* Absolute grid snap: New toggle added to increment snapping option in
  the UV editor, allows UV grid snapping during translation.

Reviewed By: campbellbarton

Ref D12684

2 files changed, 29 insertions, 19 deletions

diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 292ca726b6f..d8f4d01a2e9 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -3394,7 +3394,7 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
               SpaceImage *sima = (SpaceImage *)sl;
               sima->flag &= ~(SI_FLAG_UNUSED_0 | SI_FLAG_UNUSED_1 | SI_FLAG_UNUSED_3 |
                               SI_FLAG_UNUSED_6 | SI_FLAG_UNUSED_7 | SI_FLAG_UNUSED_8 |
-                              SI_FLAG_UNUSED_17 | SI_FLAG_UNUSED_18 | SI_FLAG_UNUSED_23 |
+                              SI_FLAG_UNUSED_17 | SI_CUSTOM_GRID | SI_FLAG_UNUSED_23 |
                               SI_FLAG_UNUSED_24);
               break;
             }
diff --git a/source/blender/blenloader/intern/versioning_300.c b/source/blender/blenloader/intern/versioning_300.c
index 3b51e40c218..ea368c0b3b1 100644
--- a/source/blender/blenloader/intern/versioning_300.c
+++ b/source/blender/blenloader/intern/versioning_300.c
@@ -1579,28 +1579,25 @@ void blo_do_versions_300(FileData *fd, Library *UNUSED(lib), Main *bmain)
     }
   }
 
-  /**
-   * Versioning code until next subversion bump goes here.
-   *
-   * \note Be sure to check when bumping the version:
-   * - "versioning_userdef.c", #blo_do_versions_userdef
-   * - "versioning_userdef.c", #do_versions_theme
-   *
-   * \note Keep this message at the bottom of the function.
-   */
-  {
-    /* Keep this block, even when empty. */
-
+  if (!MAIN_VERSION_ATLEAST(bmain, 300, 29)) {
     LISTBASE_FOREACH (bScreen *, screen, &bmain->screens) {
       LISTBASE_FOREACH (ScrArea *, area, &screen->areabase) {
         LISTBASE_FOREACH (SpaceLink *, sl, &area->spacedata) {
-          if (sl->spacetype == SPACE_SEQ) {
-            ListBase *regionbase = (sl == area->spacedata.first) ? &area->regionbase :
-                                                                   &sl->regionbase;
-            LISTBASE_FOREACH (ARegion *, region, regionbase) {
-              if (region->regiontype == RGN_TYPE_WINDOW) {
-                region->v2d.max[1] = MAXSEQ;
+          switch (sl->spacetype) {
+            case SPACE_SEQ: {
+              ListBase *regionbase = (sl == area->spacedata.first) ? &area->regionbase :
+                                                                     &sl->regionbase;
+              LISTBASE_FOREACH (ARegion *, region, regionbase) {
+                if (region->regiontype == RGN_TYPE_WINDOW) {
+                  region->v2d.max[1] = MAXSEQ;
+                }
               }
+              break;
+            }
+            case SPACE_IMAGE: {
+              SpaceImage *sima = (SpaceImage *)sl;
+              sima->custom_grid_subdiv = 10;
+              break;
             }
           }
         }
@@ -1613,4 +1610,17 @@ void blo_do_versions_300(FileData *fd, Library *UNUSED(lib), Main *bmain)
       }
     }
   }
+
+  /**
+   * Versioning code until next subversion bump goes here.
+   *
+   * \note Be sure to check when bumping the version:
+   * - "versioning_userdef.c", #blo_do_versions_userdef
+   * - "versioning_userdef.c", #do_versions_theme
+   *
+   * \note Keep this message at the bottom of the function.
+   */
+  {
+    /* Keep this block, even when empty. */
+  }
 }