UI: Add initial "grid view"

Part of T98560.
See https://wiki.blender.org/wiki/Source/Interface/Views

Adds all the basic functionality needed for grid views. They display
items in a grid of rows and columns, typically with a preview image and
a label underneath. Think of the main region in the Asset Browser.

Current features:
- Active item
- Notifier listening (also added this to the tree view)
- Performance: Skip adding buttons that are not scrolled into view
  (solves performance problems for big asset libraries, for example).
- Custom item size
- Preview items (items that draw a preview with a label underneath)
- Margins between items scale so the entire region width is filled with
  column, rather than leaving a big empty block at the right if there's
  not enough space for another column (like the File and current Asset
Browser does it).
- "Data-View Item" theme colors. Not shown in the UI yet.

No user visible changes expected since the grid views aren't used for
anything yet.

This was developed as part of a rewrite of the Asset Browser UI
(`asset-browser-grid-view` branch), see T95653. There's no reason to
keep this part in a branch, continuing development in master makes
things easier.

Grid and tree views have a lot of very similar code, so I'm planning to
unify them to a degree. I kept things separate for the start to first
find out how much and what exactly makes sense to override.

1 files changed, 14 insertions, 1 deletions

diff --git a/source/blender/editors/interface/tree_view.cc b/source/blender/editors/interface/tree_view.cc
index bf756fb5838..f86d1c4d8bc 100644
--- a/source/blender/editors/interface/tree_view.cc
+++ b/source/blender/editors/interface/tree_view.cc
@@ -68,6 +68,12 @@ void AbstractTreeView::foreach_item(ItemIterFn iter_fn, IterOptions options) con
   foreach_item_recursive(iter_fn, options);
 }
 
+bool AbstractTreeView::listen(const wmNotifier &) const
+{
+  /* Nothing by default. */
+  return false;
+}
+
 bool AbstractTreeView::is_renaming() const
 {
   return rename_buffer_ != nullptr;
@@ -82,7 +88,7 @@ void AbstractTreeView::update_from_old(uiBlock &new_block)
     return;
   }
 
-  uiTreeViewHandle *old_view_handle = ui_block_view_find_matching_in_old_block(
+  uiTreeViewHandle *old_view_handle = ui_block_tree_view_find_matching_in_old_block(
       &new_block, reinterpret_cast<uiTreeViewHandle *>(this));
   if (old_view_handle == nullptr) {
     is_reconstructed_ = true;
@@ -805,6 +811,13 @@ class TreeViewItemAPIWrapper {
 
 using namespace blender::ui;
 
+bool UI_tree_view_listen_should_redraw(const uiTreeViewHandle *view_handle,
+                                       const wmNotifier *notifier)
+{
+  const AbstractTreeView &view = *reinterpret_cast<const AbstractTreeView *>(view_handle);
+  return view.listen(*notifier);
+}
+
 bool UI_tree_view_item_is_active(const uiTreeViewItemHandle *item_handle)
 {
   const AbstractTreeViewItem &item = reinterpret_cast<const AbstractTreeViewItem &>(*item_handle);