Base selection on Excel behaviour

-- sqref is a block of selected cells containing the active_cell (normally is just == active_cell)
-- active cell is the selected vell in this selection/view/pane
-- inactive selections use the top-left cell as the active_cell

include/xlnt/worksheet/selection.hpp

@@ -36,6 +36,27 @@ namespace xlnt {
 class XLNT_API selection
 {
 public:
+    /// <summary>
+    /// default ctor
+    /// </summary>
+    explicit selection() = default;
+
+    /// <summary>
+    /// ctor when no range selected
+    /// sqref == active_cell
+    /// </summary>
+    explicit selection(pane_corner quadrant, cell_reference active_cell)
+        : active_cell_(active_cell), sqref_(range_reference(active_cell, active_cell)), pane_(quadrant)
+    {}
+
+    /// <summary>
+    /// ctor with selected range
+    /// sqref must contain active_cell
+    /// </summary>
+    explicit selection(pane_corner quadrant, cell_reference active_cell, range_reference selected)
+        : active_cell_(active_cell), sqref_(selected), pane_(quadrant)
+    {}
+
     /// <summary>
     /// Returns true if this selection has a defined active cell.
     /// </summary>
@@ -121,17 +142,18 @@ public:
 
 private:
     /// <summary>
-    /// The active cell
+    /// The last selected cell in the selection
     /// </summary>
     optional<cell_reference> active_cell_;
 
     /// <summary>
-    /// The range
+    /// The last selected block in the selection
+    /// contains active_cell_, normally == to active_cell_
     /// </summary>
     optional<range_reference> sqref_;
 
     /// <summary>
-    /// The quadrant
+    /// The corner of the worksheet that this selection extends to
     /// </summary>
     pane_corner pane_;
 };

source/worksheet/worksheet.cpp

@@ -310,42 +310,23 @@ void worksheet::freeze_panes(const cell_reference &ref)
     primary_view.pane().state = pane_state::frozen;
 
     primary_view.clear_selections();
-    primary_view.add_selection(selection());
-    primary_view.add_selection(selection());
     if (ref.column() == "A") // no column is frozen
     {
-        primary_view.selection(0).pane(pane_corner::bottom_left);
+        primary_view.add_selection(selection(pane_corner::bottom_left, ref));
-        primary_view.selection(0).sqref("A1");
-        primary_view.selection(0).active_cell(ref.make_offset(0, -1)); // cell above
-        primary_view.selection(1).pane(pane_corner::bottom_right);
-        primary_view.selection(1).sqref("A1");
-        primary_view.selection(1).active_cell(ref);
         primary_view.pane().active_pane = pane_corner::bottom_left;
         primary_view.pane().y_split = ref.row() - 1;
     }
     else if (ref.row() == 1) // no row is frozen
     {
-        primary_view.selection(0).pane(pane_corner::top_right);
+        primary_view.add_selection(selection(pane_corner::top_right, ref));
-        primary_view.selection(0).sqref("A1");
-        primary_view.selection(0).active_cell(ref.make_offset(-1, 0)); // cell to the left
-        primary_view.selection(1).pane(pane_corner::bottom_right);
-        primary_view.selection(1).sqref("A1");
-        primary_view.selection(1).active_cell(ref);
         primary_view.pane().active_pane = pane_corner::top_right;
         primary_view.pane().x_split = ref.column_index() - 1;
     }
     else // column and row is frozen
     {
-        primary_view.add_selection(selection());
+        primary_view.add_selection(selection(pane_corner::top_right, cell_reference(ref.column(), 1)));
-        primary_view.selection(0).pane(pane_corner::top_right);
+        primary_view.add_selection(selection(pane_corner::bottom_left, cell_reference(1, ref.row())));
-        primary_view.selection(0).sqref("A1");
+        primary_view.add_selection(selection(pane_corner::bottom_right, ref));
-        primary_view.selection(0).active_cell(ref.make_offset(0, -1)); // cell above
-        primary_view.selection(1).pane(pane_corner::bottom_left);
-        primary_view.selection(1).sqref("A1");
-        primary_view.selection(1).active_cell(ref.make_offset(-1, 0)); // cell to the left
-        primary_view.selection(2).pane(pane_corner::bottom_right);
-        primary_view.selection(2).sqref("A1");
-        primary_view.selection(2).active_cell(ref);
         primary_view.pane().active_pane = pane_corner::bottom_right;
         primary_view.pane().x_split = ref.column_index() - 1;
         primary_view.pane().y_split = ref.row() - 1;
@@ -373,11 +354,12 @@ void worksheet::active_cell(const cell_reference &ref)
 
     if (!primary_view.has_selections())
     {
-        primary_view.add_selection(selection());
+        primary_view.add_selection(selection(pane_corner::bottom_right, ref));
+    }
+    else
+    {
+        primary_view.selection(0).active_cell(ref);
     }
-
-    auto &primary_selection = primary_view.selection(0);
-    primary_selection.active_cell(ref);
 }
 
 bool worksheet::has_active_cell() const

tests/worksheet/worksheet_test_suite.hpp

@@ -492,10 +492,13 @@ public:
         ws.freeze_panes("A4");
 
         auto view = ws.view();
-        xlnt_assert_equals(view.selections().size(), 2);
+        xlnt_assert_equals(view.selections().size(), 1);
-        xlnt_assert_equals(view.selections()[0].active_cell(), "A3");
+        // pane is the corner of the worksheet that this selection extends to
+        // active cell is the last selected cell in the selection
+        // sqref is the last selected block in the selection
         xlnt_assert_equals(view.selections()[0].pane(), xlnt::pane_corner::bottom_left);
-        xlnt_assert_equals(view.selections()[0].sqref(), "A1"); // TODO: document sqref and clarify whether 'A1' is the intended value here
+        xlnt_assert_equals(view.selections()[0].active_cell(), "A4");
+        xlnt_assert_equals(view.selections()[0].sqref(), "A4");
         xlnt_assert_equals(view.pane().active_pane, xlnt::pane_corner::bottom_left);
         xlnt_assert_equals(view.pane().state, xlnt::pane_state::frozen);
         xlnt_assert_equals(view.pane().top_left_cell.get(), "A4");
@@ -509,10 +512,13 @@ public:
         ws.freeze_panes("D1");
 
         auto view = ws.view();
-        xlnt_assert_equals(view.selections().size(), 2);
+        xlnt_assert_equals(view.selections().size(), 1);
-        xlnt_assert_equals(view.selections()[0].active_cell(), "C1");
+        // pane is the corner of the worksheet that this selection extends to
+        // active cell is the last selected cell in the selection
+        // sqref is the last selected block in the selection
         xlnt_assert_equals(view.selections()[0].pane(), xlnt::pane_corner::top_right);
-        xlnt_assert_equals(view.selections()[0].sqref(), "A1"); // TODO: document sqref and clarify whether 'A1' is the intended value here
+        xlnt_assert_equals(view.selections()[0].active_cell(), "D1");
+        xlnt_assert_equals(view.selections()[0].sqref(), "D1");
         xlnt_assert_equals(view.pane().active_pane, xlnt::pane_corner::top_right);
         xlnt_assert_equals(view.pane().state, xlnt::pane_state::frozen);
         xlnt_assert_equals(view.pane().top_left_cell.get(), "D1");
@@ -527,11 +533,18 @@ public:
 
         auto view = ws.view();
         xlnt_assert_equals(view.selections().size(), 3);
+        // pane is the corner of the worksheet that this selection extends to
+        // active cell is the last selected cell in the selection
+        // sqref is the last selected block in the selection
         xlnt_assert_equals(view.selections()[0].pane(), xlnt::pane_corner::top_right);
+        xlnt_assert_equals(view.selections()[0].active_cell(), "D1");
+        xlnt_assert_equals(view.selections()[0].sqref(), "D1");
         xlnt_assert_equals(view.selections()[1].pane(), xlnt::pane_corner::bottom_left);
-        xlnt_assert_equals(view.selections()[2].active_cell(), "D4");
+        xlnt_assert_equals(view.selections()[1].active_cell(), "A4");
+        xlnt_assert_equals(view.selections()[1].sqref(), "A4");
         xlnt_assert_equals(view.selections()[2].pane(), xlnt::pane_corner::bottom_right);
-        xlnt_assert_equals(view.selections()[2].sqref(), "A1"); // TODO: document sqref and clarify whether 'A1' is the intended value here
+        xlnt_assert_equals(view.selections()[2].active_cell(), "D4");
+        xlnt_assert_equals(view.selections()[2].sqref(), "D4");
         xlnt_assert_equals(view.pane().active_pane, xlnt::pane_corner::bottom_right);
         xlnt_assert_equals(view.pane().state, xlnt::pane_state::frozen);
         xlnt_assert_equals(view.pane().top_left_cell.get(), "D4");