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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "chrome/browser/ui/panels/docked_panel_drag_handler.h"
      6 
      7 #include "chrome/browser/ui/panels/docked_panel_collection.h"
      8 #include "chrome/browser/ui/panels/panel.h"
      9 #include "chrome/browser/ui/panels/panel_manager.h"
     10 #include "ui/gfx/point.h"
     11 #include "ui/gfx/rect.h"
     12 
     13 // static
     14 void DockedPanelDragHandler::HandleDrag(Panel* panel,
     15                                         const gfx::Point& target_position) {
     16   DCHECK_EQ(PanelCollection::DOCKED, panel->collection()->type());
     17 
     18   DockedPanelCollection* collection =
     19       static_cast<DockedPanelCollection*>(panel->collection());
     20 
     21   // Moves this panel to the dragging position.
     22   // Note that we still allow the panel to be moved vertically until it gets
     23   // aligned to the bottom area.
     24   gfx::Rect new_bounds(panel->GetBounds());
     25   new_bounds.set_x(target_position.x());
     26   int delta_x = new_bounds.x() - panel->GetBounds().x();
     27   int bottom = collection->GetBottomPositionForExpansionState(
     28       panel->expansion_state());
     29   if (new_bounds.bottom() != bottom) {
     30     new_bounds.set_y(target_position.y());
     31     if (new_bounds.bottom() > bottom)
     32       new_bounds.set_y(bottom - new_bounds.height());
     33   }
     34   panel->SetPanelBoundsInstantly(new_bounds);
     35 
     36   if (delta_x) {
     37     // Checks and processes other affected panels.
     38     if (delta_x > 0)
     39       DragRight(panel);
     40     else
     41       DragLeft(panel);
     42 
     43     // Layout refresh will automatically recompute the bounds of all affected
     44     // panels due to their position changes.
     45     collection->RefreshLayout();
     46   }
     47 }
     48 
     49 // static
     50 void DockedPanelDragHandler::DragLeft(Panel* panel) {
     51   DockedPanelCollection* collection =
     52       static_cast<DockedPanelCollection*>(panel->collection());
     53 
     54   // This is the left corner of the dragging panel. We use it to check against
     55   // all the panels on its left.
     56   int dragging_panel_left_boundary = panel->GetBounds().x();
     57 
     58   // Checks the panels to the left of the dragging panel.
     59   DockedPanelCollection::Panels::iterator dragging_panel_iterator =
     60       find(collection->panels_.begin(), collection->panels_.end(), panel);
     61   DockedPanelCollection::Panels::iterator current_panel_iterator =
     62       dragging_panel_iterator;
     63   ++current_panel_iterator;
     64   for (; current_panel_iterator != collection->panels_.end();
     65        ++current_panel_iterator) {
     66     Panel* current_panel = *current_panel_iterator;
     67 
     68     // Can we swap dragging panel with its left panel? The criterion is that
     69     // the left corner of dragging panel should pass the middle position of
     70     // its left panel.
     71     if (dragging_panel_left_boundary > current_panel->GetBounds().x() +
     72             current_panel->GetBounds().width() / 2)
     73       break;
     74 
     75     // Swaps the contents and makes |dragging_panel_iterator| refers to the new
     76     // position.
     77     *dragging_panel_iterator = current_panel;
     78     *current_panel_iterator = panel;
     79     dragging_panel_iterator = current_panel_iterator;
     80   }
     81 }
     82 
     83 // static
     84 void DockedPanelDragHandler::DragRight(Panel* panel) {
     85   DockedPanelCollection* collection =
     86       static_cast<DockedPanelCollection*>(panel->collection());
     87 
     88   // This is the right corner of the dragging panel. We use it to check against
     89   // all the panels on its right.
     90   int dragging_panel_right_boundary = panel->GetBounds().x() +
     91       panel->GetBounds().width() - 1;
     92 
     93   // Checks the panels to the right of the dragging panel.
     94   DockedPanelCollection::Panels::iterator dragging_panel_iterator =
     95       find(collection->panels_.begin(), collection->panels_.end(), panel);
     96   DockedPanelCollection::Panels::iterator current_panel_iterator =
     97       dragging_panel_iterator;
     98   while (current_panel_iterator != collection->panels_.begin()) {
     99     current_panel_iterator--;
    100     Panel* current_panel = *current_panel_iterator;
    101 
    102     // Can we swap dragging panel with its right panel? The criterion is that
    103     // the left corner of dragging panel should pass the middle position of
    104     // its right panel.
    105     if (dragging_panel_right_boundary < current_panel->GetBounds().x() +
    106             current_panel->GetBounds().width() / 2)
    107       break;
    108 
    109     // Swaps the contents and makes |dragging_panel_iterator| refers to the new
    110     // position.
    111     *dragging_panel_iterator = current_panel;
    112     *current_panel_iterator = panel;
    113     dragging_panel_iterator = current_panel_iterator;
    114   }
    115 }
    116