Outliner: Hierarchy line drawing

Adds a new hierarchy line that draws to the left of collections. If the
collection is color tagged, then the hierarchy line is drawn in that
color. This is useful to see the color tag of a collection that exceeds
the vertical height of the outliner when expanded.

This also modifies the object hierarchy line drawing to match the new
collection hierarchy line, with no horizontal lines, and moved a unit to
the left. Object lines are not drawn colored.

Manifest Task: https://developer.blender.org/T77777

Differential Revision: https://developer.blender.org/D8622

1 files changed, 45 insertions, 84 deletions

diff --git a/source/blender/editors/space_outliner/outliner_draw.c b/source/blender/editors/space_outliner/outliner_draw.c
index 32b29e712bc..3449b73ed24 100644
--- a/source/blender/editors/space_outliner/outliner_draw.c
+++ b/source/blender/editors/space_outliner/outliner_draw.c
@@ -3334,6 +3334,17 @@ static void outliner_draw_tree_element(bContext *C,
   }
 }
 
+static bool subtree_contains_object(ListBase *lb)
+{
+  LISTBASE_FOREACH (TreeElement *, te, lb) {
+    TreeStoreElem *tselem = TREESTORE(te);
+    if (tselem->type == 0 && te->idcode == ID_OB) {
+      return true;
+    }
+  }
+  return false;
+}
+
 static void outliner_draw_hierarchy_lines_recursive(uint pos,
                                                     SpaceOutliner *space_outliner,
                                                     ListBase *lb,
@@ -3342,100 +3353,50 @@ static void outliner_draw_hierarchy_lines_recursive(uint pos,
                                                     bool draw_grayed_out,
                                                     int *starty)
 {
-  TreeElement *te, *te_vertical_line_last = NULL, *te_vertical_line_last_dashed = NULL;
-  int y1, y2, y1_dashed, y2_dashed;
+  bTheme *btheme = UI_GetTheme();
+  int y = *starty;
+  short color_tag = COLLECTION_COLOR_NONE;
 
-  if (BLI_listbase_is_empty(lb)) {
-    return;
-  }
+  /* Small vertical padding */
+  const short line_padding = UI_UNIT_Y / 4.0f;
 
-  struct {
-    int steps_num;
-    int step_len;
-    int gap_len;
-  } dash = {
-      .steps_num = 4,
-  };
-
-  dash.step_len = UI_UNIT_X / dash.steps_num;
-  dash.gap_len = dash.step_len / 2;
-
-  const uchar grayed_alpha = col[3] / 2;
-
-  /* For vertical lines between objects. */
-  y1 = y2 = y1_dashed = y2_dashed = *starty;
-  for (te = lb->first; te; te = te->next) {
-    bool draw_children_grayed_out = draw_grayed_out || (te->flag & TE_DRAGGING);
+  /* Draw vertical lines between collections */
+  bool draw_hierarchy_line;
+  LISTBASE_FOREACH (TreeElement *, te, lb) {
     TreeStoreElem *tselem = TREESTORE(te);
+    draw_hierarchy_line = false;
+    *starty -= UI_UNIT_Y;
 
-    if (draw_children_grayed_out) {
-      immUniformColor3ubvAlpha(col, grayed_alpha);
-    }
-    else {
-      immUniformColor4ubv(col);
-    }
+    /* Only draw hierarchy lines for open collections. */
+    if (TSELEM_OPEN(tselem, space_outliner) && !BLI_listbase_is_empty(&te->subtree)) {
+      if (tselem->type == TSE_LAYER_COLLECTION) {
+        draw_hierarchy_line = true;
 
-    if ((te->flag & TE_CHILD_NOT_IN_COLLECTION) == 0) {
-      /* Horizontal Line? */
-      if (tselem->type == 0 && (te->idcode == ID_OB || te->idcode == ID_SCE)) {
-        immRecti(pos, startx, *starty, startx + UI_UNIT_X, *starty - U.pixelsize);
+        Collection *collection = outliner_collection_from_tree_element(te);
+        color_tag = collection->color_tag;
 
-        /* Vertical Line? */
-        if (te->idcode == ID_OB) {
-          te_vertical_line_last = te;
-          y2 = *starty;
-        }
-        y1_dashed = *starty - UI_UNIT_Y;
+        y = *starty;
       }
-    }
-    else {
-      BLI_assert(te->idcode == ID_OB);
-      /* Horizontal line - dashed. */
-      int start = startx;
-      for (int i = 0; i < dash.steps_num; i++) {
-        immRecti(pos, start, *starty, start + dash.step_len - dash.gap_len, *starty - U.pixelsize);
-        start += dash.step_len;
+      else if (tselem->type == 0 && te->idcode == ID_OB) {
+        if (subtree_contains_object(&te->subtree)) {
+          draw_hierarchy_line = true;
+          y = *starty;
+        }
       }
 
-      te_vertical_line_last_dashed = te;
-      y2_dashed = *starty;
-    }
-
-    *starty -= UI_UNIT_Y;
-
-    if (TSELEM_OPEN(tselem, space_outliner)) {
-      outliner_draw_hierarchy_lines_recursive(pos,
-                                              space_outliner,
-                                              &te->subtree,
-                                              startx + UI_UNIT_X,
-                                              col,
-                                              draw_children_grayed_out,
-                                              starty);
+      outliner_draw_hierarchy_lines_recursive(
+          pos, space_outliner, &te->subtree, startx + UI_UNIT_X, col, draw_grayed_out, starty);
     }
-  }
-
-  if (draw_grayed_out) {
-    immUniformColor3ubvAlpha(col, grayed_alpha);
-  }
-  else {
-    immUniformColor4ubv(col);
-  }
 
-  /* Vertical line. */
-  te = te_vertical_line_last;
-  if ((te != NULL) && (te->parent || lb->first != lb->last)) {
-    immRecti(pos, startx, y1 + UI_UNIT_Y, startx + U.pixelsize, y2);
-  }
+    if (draw_hierarchy_line) {
+      if (color_tag != COLLECTION_COLOR_NONE) {
+        immUniformColor4ubv(btheme->collection_color[color_tag].color);
+      }
+      else {
+        immUniformColor4ubv(col);
+      }
 
-  /* Children that are not in the collection are always in the end of the subtree.
-   * This way we can draw their own dashed vertical lines. */
-  te = te_vertical_line_last_dashed;
-  if ((te != NULL) && (te->parent || lb->first != lb->last)) {
-    const int steps_num = ((y1_dashed + UI_UNIT_Y) - y2_dashed) / dash.step_len;
-    int start = y1_dashed + UI_UNIT_Y;
-    for (int i = 0; i < steps_num; i++) {
-      immRecti(pos, startx, start, startx + U.pixelsize, start - dash.step_len + dash.gap_len);
-      start -= dash.step_len;
+      immRecti(pos, startx, y - line_padding, startx + (U.pixelsize * 1), *starty + line_padding);
     }
   }
 }
@@ -3663,8 +3624,8 @@ static void outliner_draw_tree(bContext *C,
     GPU_scissor(0, 0, mask_x, region->winy);
   }
 
-  /* Gray hierarchy lines. */
-  starty = (int)region->v2d.tot.ymax - UI_UNIT_Y / 2 - OL_Y_OFFSET;
+  /* Draw hierarhcy lines for collections and object children. */
+  starty = (int)region->v2d.tot.ymax - OL_Y_OFFSET;
   startx = mode_column_offset + UI_UNIT_X / 2 - (U.pixelsize + 1) / 2;
   outliner_draw_hierarchy_lines(space_outliner, &space_outliner->tree, startx, &starty);