first pass at expr drag/drop in watch windows

src/raddbg/raddbg_core.c

@@ -4181,6 +4181,112 @@ rd_view_ui(Rng2F32 rect)
                 }
               }
               
+              ////////////////////////
+              //- rjf: do drag/drops
+              //
+              if(rd_drag_is_active())
+              {
+                Vec2F32 rect_dim = dim_2f32(rect);
+                ui_set_next_rect(r2f32p(0, 0, rect_dim.x, rect_dim.y));
+                UI_Box *drop_target = ui_build_box_from_stringf(UI_BoxFlag_DropSite|UI_BoxFlag_Floating, "watch_%I64x_drop", rd_regs()->view);
+                UI_Signal sig = ui_signal_from_box(drop_target);
+                if(ui_key_match(ui_drop_hot_key(), drop_target->key))
+                {
+                  Vec2F32 drop_pos = sub_2f32(ui_mouse(), rect.p0);
+                  
+                  //- rjf: obtain best fit for "previous row" drag/drops
+                  EV_Block *watches_block = &ev_nil_block;
+                  U64 best_prev_row_num = 0;
+                  F32 best_prev_row_y = 0;
+                  F32 best_prev_row_distance = inf32();
+                  {
+                    U64 local_row_idx = 0;
+                    F32 row_y = 0;
+                    EV_Row *prev_row = 0;
+                    RD_WatchRowInfo *prev_row_info = 0;
+                    for(EV_WindowedRowNode *row_node = rows.first; row_node != 0; row_node = row_node->next, local_row_idx += 1)
+                    {
+                      EV_Row *row = &row_node->row;
+                      F32 row_height = row_height_px*row->visual_size;
+                      RD_WatchRowInfo *row_info = &row_infos[local_row_idx];
+                      E_Type *block_type = e_type_from_key__cached(row->block->eval.irtree.type_key);
+                      if(rd_state->drag_drop_regs_slot == RD_RegSlot_Expr &&
+                         block_type->expand.id_from_num == E_TYPE_EXPAND_ID_FROM_NUM_FUNCTION_NAME(watches))
+                      {
+                        if(watches_block == &ev_nil_block && row_y <= drop_pos.y && drop_pos.y <= row_y + row_height)
+                        {
+                          watches_block = row->block;
+                        }
+                        F32 row_distance = abs_f32(drop_pos.y - row_y);
+                        if(row_distance <= best_prev_row_distance)
+                        {
+                          U64 row_num = ev_block_num_from_id(row->block, row->key.child_id);
+                          best_prev_row_num = row_num-1;
+                          best_prev_row_distance = row_distance;
+                          best_prev_row_y = row_y;
+                          watches_block = row->block;
+                        }
+                      }
+                      row_y += row_height;
+                      prev_row = row;
+                      prev_row_info = row_info;
+                    }
+                  }
+                  
+                  //- rjf: drop
+                  if(rd_drag_drop())
+                  {
+                    RD_RegSlot drop_slot = rd_state->drag_drop_regs_slot;
+                    RD_Regs *drop_regs = rd_state->drag_drop_regs;
+                    switch(drop_slot)
+                    {
+                      default:{}break;
+                      case RD_RegSlot_Expr:
+                      if(watches_block != &ev_nil_block)
+                      {
+                        RD_Cfg *parent_cfg = rd_cfg_from_eval_space(watches_block->eval.space);
+                        EV_Key prev_row_key = ev_key_make(ev_hash_from_key(watches_block->key), ev_block_id_from_num(watches_block, best_prev_row_num));
+                        U64 prev_row_num = ev_num_from_key(&block_ranges, prev_row_key);
+                        EV_Row *prev_row = ev_row_from_num(scratch.arena, eval_view, filter, &block_ranges, prev_row_num);
+                        RD_WatchRowInfo prev_row_info = rd_watch_row_info_from_row(scratch.arena, prev_row);
+                        RD_Cfg *prev_cfg = prev_row_info.group_cfg_child;
+                        if(parent_cfg != &rd_nil_cfg)
+                        {
+                          RD_Cfg *cfg = rd_cfg_from_id(drop_regs->cfg);
+                          if(cfg->parent == parent_cfg)
+                          {
+                            rd_cfg_unhook(cfg->parent, cfg);
+                          }
+                          else
+                          {
+                            cfg = rd_cfg_alloc();
+                            rd_cfg_equip_stringf(cfg, "watch");
+                            rd_cfg_new(cfg, rd_state->drag_drop_regs->expr);
+                          }
+                          rd_cfg_insert_child(parent_cfg, prev_cfg, cfg);
+                        }
+                      }break;
+                    }
+                  }
+                  
+                  //- rjf: draw drop position
+                  {
+                    DR_Bucket *bucket = dr_bucket_make();
+                    DR_BucketScope(bucket) UI_TagF("pop")
+                    {
+                      Vec4F32 color = ui_color_from_name(str8_lit("background"));
+                      Rng2F32 drop_line_rect = r2f32p(rect.x0,
+                                                      rect.y0 + best_prev_row_y - ui_top_font_size()*0.5f,
+                                                      rect.x1, 
+                                                      rect.y0 + best_prev_row_y + ui_top_font_size()*0.5f);
+                      R_Rect2DInst *inst = dr_rect(drop_line_rect, color, 0, 0, 1.f);
+                      inst->colors[Corner_10] = inst->colors[Corner_11] = v4f32(color.x, color.y, color.z, 0);
+                    }
+                    ui_box_equip_draw_bucket(drop_target, bucket);
+                  }
+                }
+              }
+              
               ////////////////////////
               //- rjf: build table
               //
@@ -4771,7 +4877,13 @@ rd_view_ui(Rng2F32 rect)
                                   cell->eval.space.kind == E_SpaceKind_Null)
                           {
                             RD_RegsScope(.expr = e_full_expr_string_from_key(scratch.arena, cell->eval.key))
+                            {
+                              if(cell->flags & RD_WatchCellFlag_Expr)
+                              {
+                                rd_regs()->cfg = row_info->group_cfg_child->id;
+                              }
                               rd_drag_begin(RD_RegSlot_Expr);
+                            }
                           }
                         }
                         
@@ -8252,7 +8364,7 @@ rd_window_frame(void)
           //- rjf: build catch-all panel drop-site
           //
           UI_Key catchall_drop_site_key = ui_key_from_stringf(ui_key_zero(), "catchall_drop_site_%p", panel->cfg);
-          if(build_panel) UI_Rect(panel_rect)
+          if(build_panel && rd_drag_is_active() && rd_state->drag_drop_regs_slot == RD_RegSlot_View) UI_Rect(panel_rect)
           {
             UI_Box *catchall_drop_site = ui_build_box_from_key(UI_BoxFlag_DropSite, catchall_drop_site_key);
             ui_signal_from_box(catchall_drop_site);

src/raddbg/raddbg_widgets.c

@@ -2364,7 +2364,7 @@ rd_code_slice(RD_CodeSliceParams *params, TxtPt *cursor, TxtPt *mark, S64 *prefe
                                       top_container_box->rect.y0 + (mouse_pt.line - params->line_num_range.min) * params->line_height_px,
                                       top_container_box->rect.x1,
                                       top_container_box->rect.y0 + (mouse_pt.line - params->line_num_range.min + 1) * params->line_height_px);
-      R_Rect2DInst *inst = dr_rect(pad_2f32(drop_line_rect, 8.f), color, 0, 0, 4.f);
+      R_Rect2DInst *inst = dr_rect(drop_line_rect, color, 0, 0, 1.f);
       inst->colors[Corner_10] = inst->colors[Corner_11] = v4f32(color.x, color.y, color.z, 0);
     }
     ui_box_equip_draw_bucket(text_container_box, bucket);