UI: Improve node editor breadcrumbs display

This patch upgrades node editor breadcrumbs to have slightly more
visual weight, to including the base path of object/modifier/world,
etc, have more visually pleasing spacing, and contain icons.

In the code, a generic "context path" is added to interface code.
The idea is that this could be used to draw other breadcrumbs in areas
like the property editor or the spreadsheet, and features could be added
to all of those areas at the same time.

Ideally we would be able to control the color of the breadcrumbs with a
specific theme color, but since they are drawn with the regular layout
system, that is not easily possible.

Thanks to @fabian_schempp for the original patch.

Differential Revision: https://developer.blender.org/D10413

1 files changed, 85 insertions, 0 deletions

diff --git a/source/blender/editors/interface/interface_context_path.cc b/source/blender/editors/interface/interface_context_path.cc
new file mode 100644
index 00000000000..b0f8d186afa
--- /dev/null
+++ b/source/blender/editors/interface/interface_context_path.cc
@@ -0,0 +1,85 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2021 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup edinterface
+ */
+
+#include "BLI_vector.hh"
+
+#include "BKE_screen.h"
+
+#include "RNA_access.h"
+
+#include "ED_screen.h"
+
+#include "UI_interface.h"
+#include "UI_interface.hh"
+#include "UI_resources.h"
+
+#include "WM_api.h"
+
+namespace blender::ui {
+
+void context_path_add_generic(Vector<ContextPathItem> &path,
+                              StructRNA &rna_type,
+                              void *ptr,
+                              const BIFIconID icon_override)
+{
+  /* Add the null check here to make calling functions less verbose. */
+  if (!ptr) {
+    return;
+  }
+
+  PointerRNA rna_ptr;
+  RNA_pointer_create(nullptr, &rna_type, ptr, &rna_ptr);
+  char name[128];
+  RNA_struct_name_get_alloc(&rna_ptr, name, sizeof(name), nullptr);
+
+  /* Use a blank icon by default to check whether to retrieve it automatically from the type. */
+  const BIFIconID icon = icon_override == ICON_NONE ?
+                             static_cast<BIFIconID>(RNA_struct_ui_icon(rna_ptr.type)) :
+                             icon_override;
+
+  path.append({name, static_cast<int>(icon)});
+}
+
+/* -------------------------------------------------------------------- */
+/** \name Breadcrumb Template
+ * \{ */
+
+void template_breadcrumbs(uiLayout &layout, Span<ContextPathItem> context_path)
+{
+  uiLayout *row = uiLayoutRow(&layout, true);
+  uiLayoutSetAlignment(&layout, UI_LAYOUT_ALIGN_LEFT);
+
+  for (const int i : context_path.index_range()) {
+    uiLayout *sub_row = uiLayoutRow(row, true);
+    uiLayoutSetAlignment(sub_row, UI_LAYOUT_ALIGN_LEFT);
+
+    if (i > 0) {
+      uiItemL(sub_row, "", ICON_RIGHTARROW_THIN);
+    }
+    uiItemL(sub_row, context_path[i].name.c_str(), context_path[i].icon);
+  }
+}
+
+}  // namespace blender::ui
+
+/** \} */
\ No newline at end of file