source/blender/blenloader/intern/versioning_300.cc

@@ -4184,6 +4184,26 @@ void blo_do_versions_300(FileData *fd, Library * /*lib*/, Main *bmain)
           if (sl->spacetype == SPACE_VIEW3D) {
             ListBase *regionbase = (sl == area->spacedata.first) ? &area->regionbase :
                                                                    &sl->regionbase;
+
+            /* TODO for old files saved with the branch only. */
+            {
+              SpaceType *space_type = BKE_spacetype_from_id(sl->spacetype);
+
+              if (ARegion *asset_shelf = BKE_region_find_in_listbase_by_type(
+                      regionbase, RGN_TYPE_ASSET_SHELF)) {
+                BLI_remlink(regionbase, asset_shelf);
+                BKE_area_region_free(space_type, asset_shelf);
+                MEM_freeN(asset_shelf);
+              }
+
+              if (ARegion *asset_shelf_footer = BKE_region_find_in_listbase_by_type(
+                      regionbase, RGN_TYPE_ASSET_SHELF_FOOTER)) {
+                BLI_remlink(regionbase, asset_shelf_footer);
+                BKE_area_region_free(space_type, asset_shelf_footer);
+                MEM_freeN(asset_shelf_footer);
+              }
+            }
+
             {
               ARegion *new_asset_shelf_footer = do_versions_add_region_if_not_found(
                   regionbase,
@@ -4196,14 +4216,20 @@ void blo_do_versions_300(FileData *fd, Library * /*lib*/, Main *bmain)
               }
             }
             {
-              ARegion *new_asset_shelf = do_versions_add_region_if_not_found(
-                  regionbase,
-                  RGN_TYPE_ASSET_SHELF,
-                  "asset shelf for view3d (versioning)",
-                  RGN_TYPE_ASSET_SHELF_FOOTER);
-              if (new_asset_shelf != nullptr) {
-                new_asset_shelf->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
-                new_asset_shelf->flag |= RGN_FLAG_DYNAMIC_SIZE;
+              ARegion *asset_shelf = BKE_region_find_in_listbase_by_type(regionbase,
+                                                                         RGN_TYPE_ASSET_SHELF);
+              /* TODO for old files saved with the branch only. */
+              if (asset_shelf) {
+                asset_shelf->flag &= ~RGN_FLAG_DYNAMIC_SIZE;
+              }
+              else {
+                ARegion *new_asset_shelf = do_versions_add_region_if_not_found(
+                    regionbase,
+                    RGN_TYPE_ASSET_SHELF,
+                    "asset shelf for view3d (versioning)",
+                    RGN_TYPE_ASSET_SHELF_FOOTER);
+                new_asset_shelf->alignment = RGN_ALIGN_BOTTOM;
+                new_asset_shelf->flag |= RGN_FLAG_HIDDEN;
               }
             }
           }

source/blender/editors/asset/ED_asset_shelf.h

@@ -24,10 +24,13 @@ struct wmWindowManager;
 
 /** Only needed for #RGN_TYPE_ASSET_SHELF (not #RGN_TYPE_ASSET_SHELF_FOOTER). */
 void ED_asset_shelf_region_init(ARegion *region);
+int ED_asset_shelf_region_snap(const ARegion *region, int size, int axis);
 void ED_asset_shelf_region_listen(const struct wmRegionListenerParams *params);
 void ED_asset_shelf_region_draw(const bContext *C,
                                 struct ARegion *region,
                                 struct AssetShelfSettings *shelf_settings);
+int ED_asset_shelf_region_default_tile_height(void);
+int ED_asset_shelf_region_prefsizey(void);
 
 void ED_asset_shelf_footer_region_init(struct wmWindowManager *wm, struct ARegion *region);
 void ED_asset_shelf_footer_region(const struct bContext *C, struct ARegion *region);

source/blender/editors/asset/intern/asset_shelf.cc

@@ -6,6 +6,8 @@
  * General asset shelf code, mostly region callbacks, drawing and context stuff.
  */
 
+#include <algorithm>
+
 #include "AS_asset_catalog_path.hh"
 
 #include "BKE_context.h"
@@ -88,6 +90,56 @@ void ED_asset_shelf_region_init(ARegion *region)
   v2d.keepofs = V2D_LOCKOFS_X;
 }
 
+static constexpr int main_region_padding_y_not_scaled()
+{
+  return 2;
+}
+
+static int main_region_padding_y_scaled()
+{
+  return main_region_padding_y_not_scaled() * UI_SCALE_FAC;
+}
+
+static int main_region_padding_x_scaled()
+{
+  return 2 * UI_SCALE_FAC;
+}
+
+int ED_asset_shelf_region_snap(const ARegion *region, const int size, const int axis)
+{
+  /* Only on Y axis. */
+  if (axis != 1) {
+    return size;
+  }
+
+  const int size_scaled = size * UI_SCALE_FAC;
+
+  /* Using X axis avoids slight feedback loop when adjusting Y. */
+  const float aspect = BLI_rctf_size_x(&region->v2d.cur) /
+                       (BLI_rcti_size_x(&region->v2d.mask) + 1);
+  const float tile_size = ED_asset_shelf_region_default_tile_height() / aspect;
+  const int region_padding = main_region_padding_y_scaled();
+
+  /* How many rows fit into the region (accounting for padding). */
+  const int rows = std::max(1, int((size_scaled - 2 * region_padding) / tile_size));
+
+  const int new_size_scaled = (rows * tile_size + 2 * region_padding);
+  return new_size_scaled / UI_SCALE_FAC;
+}
+
+int ED_asset_shelf_region_default_tile_height()
+{
+  return UI_preview_tile_size_x() * 0.8f;
+}
+
+int ED_asset_shelf_region_prefsizey()
+{
+  /* Can't account for DPI here since this is expected to be called on region type initialization
+   * at startup, when #U isn't available yet. */
+
+  return ED_asset_shelf_region_default_tile_height() + 2 * main_region_padding_y_not_scaled();
+}
+
 /**
  * Check if there is any asset shelf type returning true in it's poll. If not, no asset shelf
  * region should be displayed.
@@ -123,13 +175,14 @@ void ED_asset_shelf_region_draw(const bContext *C,
   uiBlock *block = UI_block_begin(C, region, __func__, UI_EMBOSS);
 
   const uiStyle *style = UI_style_get();
-  const float padding = style->panelouter;
+  const float padding_y = main_region_padding_y_scaled();
+  const float padding_x = main_region_padding_x_scaled();
   uiLayout *layout = UI_block_layout(block,
                                      UI_LAYOUT_VERTICAL,
                                      UI_LAYOUT_PANEL,
-                                     padding,
-                                     -padding,
-                                     region->winx - 2 * padding,
+                                     padding_x,
+                                     -padding_y,
+                                     region->winx - 2 * padding_x,
                                      1,
                                      0,
                                      style);

source/blender/editors/asset/intern/asset_shelf_asset_view.cc

@@ -17,6 +17,7 @@
 #include "ED_asset_handle.h"
 #include "ED_asset_list.h"
 #include "ED_asset_list.hh"
+#include "ED_asset_shelf.h"
 
 #include "UI_grid_view.hh"
 #include "UI_interface.h"
@@ -184,9 +185,13 @@ void build_asset_view(uiLayout &layout,
     return;
   }
 
+  /* TODO deduplicate from #ED_asset_shelf_region_snap() */
+  const float aspect = BLI_rctf_size_x(&region.v2d.cur) / (BLI_rcti_size_x(&region.v2d.mask) + 1);
+  const float tile_size = ED_asset_shelf_region_default_tile_height() / aspect;
+
   std::unique_ptr asset_view = std::make_unique<AssetView>(library_ref, const_cast<bContext &>(C));
   asset_view->set_catalog_filter(catalog_filter_from_shelf_settings(shelf_settings, *library));
-  asset_view->set_tile_size(UI_preview_tile_size_x() * 0.8, UI_preview_tile_size_y() * 0.8);
+  asset_view->set_tile_size(tile_size, tile_size);
 
   uiBlock *block = uiLayoutGetBlock(&layout);
   ui::AbstractGridView *grid_view = UI_block_add_view(

source/blender/editors/screen/area.cc

@@ -1249,9 +1249,7 @@ bool ED_region_is_overlap(int spacetype, int regiontype)
                RGN_TYPE_UI,
                RGN_TYPE_TOOL_PROPS,
                RGN_TYPE_FOOTER,
-               RGN_TYPE_TOOL_HEADER,
-               RGN_TYPE_ASSET_SHELF,
-               RGN_TYPE_ASSET_SHELF_FOOTER)) {
+               RGN_TYPE_TOOL_HEADER)) {
         return true;
       }
     }
@@ -1308,6 +1306,11 @@ static void region_rect_recursive(
     }
   }
 
+  if (const int snap_flags = ED_region_snap_size_test(region)) {
+    /* Apply snapping, which updates #ARegion.sizex/sizey values. */
+    ED_region_snap_size_apply(region, snap_flags);
+  }
+
   /* `prefsizex/y`, taking into account DPI. */
   int prefsizex = UI_SCALE_FAC *
                   ((region->sizex > 1) ? region->sizex + 0.5f : region->type->prefsizex);

source/blender/editors/screen/screen_ops.c

@@ -2789,14 +2789,16 @@ static int region_scale_modal(bContext *C, wmOperator *op, const wmEvent *event)
 
         const int size_no_snap = rmd->origval + delta;
         rmd->region->sizex = size_no_snap;
+        CLAMP(rmd->region->sizex, 0, rmd->maxsize);
 
         if (rmd->region->type->snap_size) {
           short sizex_test = rmd->region->type->snap_size(rmd->region, rmd->region->sizex, 0);
-          if (abs(rmd->region->sizex - sizex_test) < snap_size_threshold) {
+          if ((abs(rmd->region->sizex - sizex_test) < snap_size_threshold) &&
+              (sizex_test <= rmd->maxsize)) {
             rmd->region->sizex = sizex_test;
           }
         }
-        CLAMP(rmd->region->sizex, 0, rmd->maxsize);
+        BLI_assert(rmd->region->sizex <= rmd->maxsize);
 
         if (size_no_snap < UI_UNIT_X / aspect) {
           rmd->region->sizex = rmd->origval;
@@ -2822,14 +2824,16 @@ static int region_scale_modal(bContext *C, wmOperator *op, const wmEvent *event)
 
         const int size_no_snap = rmd->origval + delta;
         rmd->region->sizey = size_no_snap;
+        CLAMP(rmd->region->sizey, 0, rmd->maxsize);
 
         if (rmd->region->type->snap_size) {
           short sizey_test = rmd->region->type->snap_size(rmd->region, rmd->region->sizey, 1);
-          if (abs(rmd->region->sizey - sizey_test) < snap_size_threshold) {
+          if ((abs(rmd->region->sizey - sizey_test) < snap_size_threshold) &&
+              (sizey_test <= rmd->maxsize)) {
             rmd->region->sizey = sizey_test;
           }
         }
-        CLAMP(rmd->region->sizey, 0, rmd->maxsize);
+        BLI_assert(rmd->region->sizey <= rmd->maxsize);
 
         /* NOTE: `UI_UNIT_Y / 4` means you need to drag the footer and execute region
          * almost all the way down for it to become hidden, this is done

source/blender/editors/space_view3d/space_view3d.cc

@@ -303,7 +303,8 @@ static SpaceLink *view3d_create(const ScrArea * /*area*/, const Scene *scene)
 
   BLI_addtail(&v3d->regionbase, region);
   region->regiontype = RGN_TYPE_ASSET_SHELF;
-  region->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
+  region->alignment = RGN_ALIGN_BOTTOM;
+  region->flag = RGN_FLAG_HIDDEN;
 
   /* main region */
   region = MEM_cnew<ARegion>("main region for view3d");
@@ -2254,10 +2255,11 @@ void ED_spacetype_view3d()
   /* regions: asset shelf */
   art = MEM_cnew<ARegionType>("spacetype view3d asset shelf region");
   art->regionid = RGN_TYPE_ASSET_SHELF;
-  art->prefsizey = HEADERY * 3.5f;
+  art->prefsizey = ED_asset_shelf_region_prefsizey();
   art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_ASSET_SHELF | ED_KEYMAP_VIEW2D | ED_KEYMAP_FRAMES |
                     ED_KEYMAP_HEADER;
   art->listener = ED_asset_shelf_region_listen;
+  art->snap_size = ED_asset_shelf_region_snap;
   art->context = view3d_asset_shelf_context;
   art->init = view3d_asset_shelf_region_init;
   art->draw = view3d_asset_shelf_region_draw;