start on gap buffer drawing

src/gui/Window.cc

@@ -378,6 +378,30 @@ void Window::update_cursor_row()
 void Window::draw_buffer()
 {
     update_cursor_row();
+    int screen_row = m_cursor_row - m_cursor->column() / m_columns;
+    GapBuffer::Cursor draw_cursor = *m_cursor;
+    draw_cursor.go_start_of_line();
+    while ((screen_row > 0) && draw_cursor.go_up(0u))
+    {
+        GapBuffer::Cursor cursor2 = draw_cursor;
+        cursor2.go_end_of_line(false);
+        screen_row -= (1 + cursor2.column() / m_columns);
+    }
+    while (screen_row < m_rows)
+    {
+        draw_buffer_line(screen_row, draw_cursor);
+        draw_cursor.go_end_of_line(false);
+        screen_row += (1 + draw_cursor.column() / m_columns);
+        if (!draw_cursor.go_down(0u))
+        {
+            break;
+        }
+    }
+}
+
+void Window::draw_buffer_line(int screen_row, const GapBuffer::Cursor & cursor)
+{
+    /* TODO */
 }
 
 void Window::draw_buffer_character(int screen_column, int screen_row, uint32_t character)

src/gui/Window.h

@@ -45,6 +45,7 @@ protected:
     void handle_keyval(uint32_t keyval);
     void cursor_move(int which);
     void draw_buffer();
+    void draw_buffer_line(int screen_row, const GapBuffer::Cursor & cursor);
     void draw_buffer_character(int screen_column, int screen_row, uint32_t character);
     void draw_character(int x, int y, uint32_t character);
     void update_cursor_row();