Add H, M, L commands to move cursor within screen

src/core/BufferView.cc

@@ -191,6 +191,15 @@ bool BufferView::cursor_move(CursorMovement which, uint32_t c, bool allow_eol)
     case CursorMovement::BACK_ON_TO_CHAR:
         moved = m_iterator->go_backward_in_line_on_to_char(c);
         break;
+    case CursorMovement::TOP_OF_SCREEN:
+        moved = cursor_move_to_screen_position(0, effective_scroll_offset(), allow_eol);
+        break;
+    case CursorMovement::MIDDLE_OF_SCREEN:
+        moved = cursor_move_to_screen_position(0, m_height / 2, allow_eol);
+        break;
+    case CursorMovement::BOTTOM_OF_SCREEN:
+        moved = cursor_move_to_screen_position(0, m_height - effective_scroll_offset() - 1, allow_eol);
+        break;
     }
     if (moved)
     {
@@ -223,6 +232,12 @@ bool BufferView::cursor_move(CursorMovement which, uint32_t c, bool allow_eol)
         case CursorMovement::LAST_LINE:
             m_cursor_screen_row = m_height - 1;
             break;
+        case CursorMovement::TOP_OF_SCREEN:
+        case CursorMovement::MIDDLE_OF_SCREEN:
+        case CursorMovement::BOTTOM_OF_SCREEN:
+            m_target_virtual_column = 0;
+            m_target_screen_column = 0;
+            break;
         }
     }
 
@@ -266,6 +281,41 @@ bool BufferView::cursor_move_to_line(size_t target_line)
     return false;
 }
 
+bool BufferView::cursor_move_to_screen_position(int x, int y, bool allow_eol)
+{
+    bool moved = false;
+    for (const LineDescriptor & screen_line : m_lines)
+    {
+        if ((y >= screen_line.row_offset) &&
+                (y < (screen_line.row_offset + screen_line.n_rows)))
+        {
+            Buffer::Iterator scan_iter = *m_iterator;
+            bool set = false;
+            int desired_row_offset = y - screen_line.row_offset;
+            for (auto it = horiz_iter(screen_line.line); it.is_valid(); it++)
+            {
+                if (it.row_offset() == desired_row_offset)
+                {
+                    if ((!set) ||
+                            ((it.screen_column() <= x) && (allow_eol || (!it.is_eol()))))
+                    {
+                        scan_iter = *it.iterator();
+                        set = true;
+                    }
+                }
+            }
+            if (scan_iter != *m_iterator)
+            {
+                *m_iterator = scan_iter;
+                moved = true;
+                determine_new_cursor_screen_row();
+            }
+            break;
+        }
+    }
+    return moved;
+}
+
 void BufferView::scroll_view_up(int n_lines, bool allow_eol)
 {
     int orig_cursor_screen_row = m_cursor_screen_row;

src/core/BufferView.h

@@ -32,6 +32,9 @@ public:
         FORWARD_ON_TO_CHAR,
         BACK_UP_TO_CHAR,
         BACK_ON_TO_CHAR,
+        TOP_OF_SCREEN,
+        MIDDLE_OF_SCREEN,
+        BOTTOM_OF_SCREEN,
     };
 
     class Iterator
@@ -84,6 +87,7 @@ public:
     }
     bool cursor_move(CursorMovement which, uint32_t c, bool allow_eol);
     bool cursor_move_to_line(size_t line);
+    bool cursor_move_to_screen_position(int x, int y, bool allow_eol);
     int cursor_screen_row() const { return m_cursor_screen_row; }
     int cursor_screen_column() const { return m_cursor_screen_column; }
     int cursor_virtual_column() const { return m_cursor_virtual_column; }
@@ -112,6 +116,7 @@ protected:
     int m_cursor_screen_row;
     int m_cursor_screen_column;
     int m_cursor_virtual_column;
+    /** Holds the screen row offset of the cursor in the current line */
     int m_cursor_row_offset;
     int m_rows_in_cursor_line;
     int m_target_screen_column;

src/core/Command.h

@@ -42,6 +42,9 @@ public:
         GO_RIGHT,
         GO_START_OF_LINE,
         GO_END_OF_LINE,
+        GO_TOP_OF_SCREEN,
+        GO_MIDDLE_OF_SCREEN,
+        GO_BOTTOM_OF_SCREEN,
         NEXT,
         PREV,
         SCROLL_WINDOW_UP_ONE_LINE,

src/core/DefaultCommandMap.cc

@@ -47,9 +47,11 @@ static void build_command_mode()
     dcm->add("gg", Command::GO_TO_LINE, nullptr, false);
     dcm->add("G", Command::GO_TO_LAST_LINE, nullptr, false);
     dcm->add("h", Command::GO_LEFT, nullptr, false);
+    dcm->add("H", Command::GO_TOP_OF_SCREEN, nullptr, false);
     dcm->add("j", Command::GO_DOWN, nullptr, false);
     dcm->add("k", Command::GO_UP, nullptr, false);
     dcm->add("l", Command::GO_RIGHT, nullptr, false);
+    dcm->add("L", Command::GO_BOTTOM_OF_SCREEN, nullptr, false);
     dcm->add(":", Command::ENTER_COMMAND_LINE_PROMPT, nullptr, false);
 
     dcm->add("x", Command::DELETE_CHAR, nullptr, false);
@@ -59,6 +61,7 @@ static void build_command_mode()
     dcm->add({JES_KEY_MODS_CTRL + 'b'}, Command::SCROLL_WINDOW_UP_WHOLE_SCREEN, nullptr, false);
     dcm->add("n", Command::NEXT, nullptr, false);
     dcm->add("N", Command::PREV, nullptr, false);
+    dcm->add("M", Command::GO_MIDDLE_OF_SCREEN, nullptr, false);
 
     dcm->add({JES_KEY_HOME}, Command::GO_START_OF_LINE, nullptr, false);
     dcm->add({JES_KEY_MODS_CTRL + JES_KEY_HOME}, Command::GO_START_OF_FILE, nullptr, false);

src/gui/Window.cc

@@ -418,6 +418,15 @@ void Window::execute_command(const Command & command)
     case Command::GO_END_OF_LINE:
         m_focused_buffer_pane->cursor_move(BufferPane::CursorMovement::EOL, 0u);
         break;
+    case Command::GO_TOP_OF_SCREEN:
+        m_focused_buffer_pane->cursor_move(BufferPane::CursorMovement::TOP_OF_SCREEN, 0u);
+        break;
+    case Command::GO_MIDDLE_OF_SCREEN:
+        m_focused_buffer_pane->cursor_move(BufferPane::CursorMovement::MIDDLE_OF_SCREEN, 0u);
+        break;
+    case Command::GO_BOTTOM_OF_SCREEN:
+        m_focused_buffer_pane->cursor_move(BufferPane::CursorMovement::BOTTOM_OF_SCREEN, 0u);
+        break;
     case Command::NEXT:
         break;
     case Command::PREV: