Add support for dragging to reorder in Fl_Tree, STR #2828 (I)

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10275 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/Fl_Tree.H

@@ -317,7 +317,8 @@ enum Fl_Tree_Reason {
   FL_TREE_REASON_RESELECTED,	///< an item was re-selected (e.g. double-clicked)
 #endif /*FLTK_ABI_VERSION*/
   FL_TREE_REASON_OPENED,	///< an item was opened
-  FL_TREE_REASON_CLOSED		///< an item was closed
+  FL_TREE_REASON_CLOSED,	///< an item was closed
+  FL_TREE_REASON_DRAGGED	///< an item was dragged into a new place
 };
 
 class FL_EXPORT Fl_Tree : public Fl_Group {

FL/Fl_Tree_Prefs.H

@@ -67,8 +67,10 @@ enum Fl_Tree_Connector {
 enum Fl_Tree_Select {
   FL_TREE_SELECT_NONE=0,	///< Nothing selected when items are clicked
   FL_TREE_SELECT_SINGLE=1,	///< Single item selected when item is clicked (default)
-  FL_TREE_SELECT_MULTI=2	///< Multiple items can be selected by clicking
+  FL_TREE_SELECT_MULTI=2,	///< Multiple items can be selected by clicking
   				///< with SHIFT, CTRL or mouse drags.
+  FL_TREE_SELECT_SINGLE_DRAGGABLE=3, ///< Single items may be selected, and they may be
+                                     ///< reordered by mouse drag.
 };
 
 #if FLTK_ABI_VERSION >= 10301

src/Fl_Tree.cxx

@@ -328,6 +328,7 @@ int Fl_Tree::handle(int e) {
 		case FL_TREE_SELECT_NONE:
 		  break;					// ignore, let group have shot at event
 		case FL_TREE_SELECT_SINGLE:
+		case FL_TREE_SELECT_SINGLE_DRAGGABLE:
 		  if ( is_ctrl ) {				// CTRL-SPACE: (single mode) toggle
 		    if ( ! _item_focus->is_selected() ) {
 		      select_only(_item_focus, when());
@@ -389,6 +390,7 @@ int Fl_Tree::handle(int e) {
 		switch ( _prefs.selectmode() ) {
 		  case FL_TREE_SELECT_NONE:
 		  case FL_TREE_SELECT_SINGLE:
+		  case FL_TREE_SELECT_SINGLE_DRAGGABLE:
 		    break;
 		  case FL_TREE_SELECT_MULTI:
 		    // Do a 'select all'
@@ -432,6 +434,7 @@ int Fl_Tree::handle(int e) {
 	  case FL_TREE_SELECT_NONE:
 	    break;
 	  case FL_TREE_SELECT_SINGLE:
+	  case FL_TREE_SELECT_SINGLE_DRAGGABLE:
 	  case FL_TREE_SELECT_MULTI:
 	    deselect_all();
 	    break;
@@ -449,6 +452,7 @@ int Fl_Tree::handle(int e) {
 	    case FL_TREE_SELECT_NONE:
 	      break;
 	    case FL_TREE_SELECT_SINGLE:
+	    case FL_TREE_SELECT_SINGLE_DRAGGABLE:
 	      select_only(item, when());		// select only this item (handles redraw)
 	      _lastselect = item;
 	      break;
@@ -511,7 +515,8 @@ int Fl_Tree::handle(int e) {
 #endif
       if ( !item ) break;			// not near item? ignore drag event
       ret |= 1;					// acknowledge event
-      set_item_focus(item);			// becomes new focus item
+      if (_prefs.selectmode() != FL_TREE_SELECT_SINGLE_DRAGGABLE)
+        set_item_focus(item);			// becomes new focus item
       if (item==_lastselect) break;		// same item as before? avoid reselect
 
       // Handle selection behavior
@@ -522,6 +527,11 @@ int Fl_Tree::handle(int e) {
 	  select_only(item, when());		// select only this item (handles redraw)
 	  break;
 	}
+	case FL_TREE_SELECT_SINGLE_DRAGGABLE: {
+	  item = _lastselect; // Keep the source intact
+	  redraw();
+	  break;
+	}
 	case FL_TREE_SELECT_MULTI: {
 	  Fl_Tree_Item *from = next_visible_item(_lastselect, dir); // avoid reselecting item
 	  Fl_Tree_Item *to = item;
@@ -535,6 +545,57 @@ int Fl_Tree::handle(int e) {
       break;
     }
     case FL_RELEASE:
+      if (_prefs.selectmode() == FL_TREE_SELECT_SINGLE_DRAGGABLE &&
+          Fl::event_button() == FL_LEFT_MOUSE) {
+#if FLTK_ABI_VERSION >= 10303
+        Fl_Tree_Item *item = _root->find_clicked(_prefs, 1); // item we're on, vertically
+#else
+        Fl_Tree_Item *item = _root->find_clicked(_prefs); // item we're on, vertically
+#endif
+
+        if (item && _lastselect && item != _lastselect &&
+            Fl::event_x() >= item->label_x()) {
+          //printf("Would drag '%s' to '%s'\n", _lastselect->label(), item->label());
+          // Are we dropping above or below the target item?
+          const int h = Fl::event_y() - item->y();
+          const int mid = item->h() / 2;
+          const bool before = h < mid;
+          //printf("Dropping %s it\n", before ? "before" : "after");
+
+          // Do nothing if it would be a no-op
+          if ((before && prev(item) != _lastselect) ||
+              (!before && next(item) != _lastselect)) {
+            Fl_Tree_Item *parent = item->parent();
+
+            if (parent) {
+              int pos = parent->find_child(item);
+              if (!before)
+                pos++;
+
+              // Special case: trying to drop right before a folder
+              if (item->children() && item->is_open() && !before) {
+                parent = item;
+                pos = 0;
+              }
+
+              // If we're moving inside the same parent, use the below/above methods
+              if (_lastselect->parent() == parent) {
+                if (before) {
+                  _lastselect->move_above(item);
+                } else {
+                  _lastselect->move_below(item);
+                }
+              } else {
+                _lastselect->move_into(parent, pos);
+              }
+
+              redraw();
+              do_callback_for_item(_lastselect, FL_TREE_REASON_DRAGGED);
+            }
+          }
+        }
+        redraw();
+      } // End single-drag check
       ret |= 1;
       break;
   }
@@ -750,6 +811,29 @@ void Fl_Tree::draw() {
 	     _vscroll->w(),
 	     _hscroll->h());
   }
+
+  // Draw dragging line
+  if (_prefs.selectmode() == FL_TREE_SELECT_SINGLE_DRAGGABLE &&
+      Fl::pushed() == this) {
+
+    Fl_Tree_Item *item = _root->find_clicked(_prefs, 1); // item we're on, vertically
+    if (item && item != _item_focus) {
+      // Are we dropping above or before the target item?
+      const int h = Fl::event_y() - item->y();
+      const int mid = item->h() / 2;
+      const bool before = h < mid;
+
+      fl_color(FL_BLACK);
+
+      int tgt;
+      if (before) {
+        tgt = item->y();
+      } else {
+        tgt = item->y() + item->h();
+      }
+      fl_line(item->x(), tgt, item->x() + item->w(), tgt);
+    }
+  }
 }
 #else
 /// Standard FLTK draw() method, handles drawing the tree widget.
@@ -775,6 +859,29 @@ void Fl_Tree::draw() {
     }
     Fl::add_timeout(.10, redraw_soon, (void*)this);	// use timer to trigger redraw; we can't
   }
+
+  // Draw dragging line
+  if (_prefs.selectmode() == FL_TREE_SELECT_SINGLE_DRAGGABLE &&
+      Fl::pushed() == this) {
+
+    Fl_Tree_Item *item = _root->find_clicked(_prefs); // item we're on, vertically
+    if (item && item != _item_focus) {
+      // Are we dropping above or before the target item?
+      const int h = Fl::event_y() - item->y();
+      const int mid = item->h() / 2;
+      const bool before = h < mid;
+
+      fl_color(FL_BLACK);
+
+      int tgt;
+      if (before) {
+        tgt = item->y();
+      } else {
+        tgt = item->y() + item->h();
+      }
+      fl_line(item->x(), tgt, item->x() + item->w(), tgt);
+    }
+  }
 }
 
 // This method is undocumented, and has been removed in ABI 1.3.3

test/tree.fl

@@ -51,6 +51,7 @@ Function {reason_as_name(Fl_Tree_Reason reason)} {
       case FL_TREE_REASON_DESELECTED: return("deselected");
       case FL_TREE_REASON_OPENED:     return("opened");
       case FL_TREE_REASON_CLOSED:     return("closed");
+      case FL_TREE_REASON_DRAGGED:    return("dragged");
 \#if FLTK_ABI_VERSION >= 10301
 	  case FL_TREE_REASON_RESELECTED: return("reselected");
 \#endif
@@ -345,7 +346,7 @@ Function {} {open
 } {
   Fl_Window window {
     label tree open
-    xywh {0 234 1045 580} type Double visible
+    xywh {1 234 1045 580} type Double visible
   } {
     Fl_Group tree {
       label Tree
@@ -637,8 +638,9 @@ switch ( selectmode_chooser->value() ) {
     case 0:  tree->selectmode(FL_TREE_SELECT_NONE);   break;	// None
     case 1:  tree->selectmode(FL_TREE_SELECT_SINGLE); break;	// Single
     case 2:  tree->selectmode(FL_TREE_SELECT_MULTI);  break; 	// Multi
+    case 3:  tree->selectmode(FL_TREE_SELECT_SINGLE_DRAGGABLE);  break; // Single draggable
     default: tree->selectmode(FL_TREE_SELECT_SINGLE); break;	// Single
-}}
+}} open selected
         tooltip {Tests Fl_Tree::selectmode()
 Sets how Fl_Tree handles mouse selection of tree items.
     NONE	-- Not selectable by keyboard/mouse
@@ -659,6 +661,10 @@ Sets how Fl_Tree handles mouse selection of tree items.
           label Multi
           xywh {60 60 36 21} labelsize 12
         }
+        MenuItem {} {
+          label {Single + drag}
+          xywh {70 70 36 21} labelsize 12
+        }
       }
       Fl_Choice reselectmode_chooser {
         label {Item Reselect Mode}
@@ -1393,7 +1399,7 @@ if ( !item) {
 }
 int onoff = rootselect2_toggle->value();
 if ( onoff ) tree->select_all(item);	// select /ROOT and its children
-else         tree->deselect_all(item);	// deselect /ROOT and its children} selected
+else         tree->deselect_all(item);	// deselect /ROOT and its children}
         tooltip {Toggle selection of the ROOT item and all children} xywh {914 219 95 16} selection_color 1 labelsize 9
       }
       Fl_Box {} {
@@ -1728,8 +1734,7 @@ helpwin->show();}
         callback {tree->scrollbar_size((int)tree_scrollbar_size_slider->value());
 tree->redraw();}
         tooltip {Tests Fl_Tree::scrollbar_size() effects on tree clipping.
-The value is normally 0, which causes Fl_Tree to use the global Fl::scrollbar_size() instead.
-} xywh {835 499 180 16} type Horizontal color 46 selection_color 1 labelsize 11 align 4 textsize 9
+The value is normally 0, which causes Fl_Tree to use the global Fl::scrollbar_size() instead.} xywh {835 499 180 16} type Horizontal color 46 selection_color 1 labelsize 11 align 4 textsize 9
         code0 {o->value(tree->scrollbar_size());}
         code1 {o->range(0.0, 30.0);}
         code2 {o->step(1.0);}