Add position offset to Window to limit moves with search menu style

Window can be resized with an "offset_pos" flag, which means that
the resize took place on the top left corner of the window, leading
to a change in current window position. This is treated as temporary
and the position change is stored in a m_position_offset field.

That allows the ncurses UI to offset the position when it displays
a Search menu, so that the window does not constantly scroll when
the search menu open/closes. The window will only scroll if it needs
to in order to keep the main selectin visible.

src/client.cc

@@ -48,9 +48,9 @@ Client::Client(std::unique_ptr<UserInterface>&& ui,
     m_ui->set_on_key([this](Key key) {
         if (key == ctrl('c'))
             killpg(getpgrp(), SIGINT);
-        else if (key.modifiers == Key::Modifiers::Resize)
+        else if (key.modifiers & Key::Modifiers::Resize)
         {
-            m_window->set_dimensions(m_ui->dimensions());
+            m_window->set_dimensions(key.coord(), key.modifiers & Key::Modifiers::OffsetPos);
             force_redraw();
         }
         else

src/keys.hh

@@ -30,7 +30,8 @@ struct Key
                      MouseWheelDown | MouseWheelUp,
 
         Resize = 1 << 8,
-        MenuSelect = 1 << 9,
+        OffsetPos = 1 << 9,
+        MenuSelect = 1 << 10,
     };
     enum NamedKey : Codepoint
     {
@@ -112,7 +113,7 @@ constexpr Key ctrl(Key key)
 
 constexpr Codepoint encode_coord(DisplayCoord coord) { return (Codepoint)(((int)coord.line << 16) | ((int)coord.column & 0x0000FFFF)); }
 
-constexpr Key resize(DisplayCoord dim) { return { Key::Modifiers::Resize, encode_coord(dim) }; }
+constexpr Key resize(DisplayCoord dim, Key::Modifiers additional = Key::Modifiers::None) { return { Key::Modifiers::Resize | additional, encode_coord(dim) }; }
 
 constexpr size_t hash_value(const Key& key) { return hash_values(key.modifiers, key.key); }
 

src/ncurses_ui.cc

@@ -228,12 +228,6 @@ static void signal_handler(int)
     EventManager::instance().force_signal(0);
 }
 
-static void do_ungetch(int ch)
-{
-    ungetch(ch);
-    EventManager::instance().force_signal(0);
-}
-
 static const std::initializer_list<HashMap<Kakoune::Color, int>::Item>
 default_colors = {
     { Color::Default,       -1 },
@@ -401,20 +395,21 @@ void NCursesUI::draw(const DisplayBuffer& display_buffer,
 
     check_resize();
 
+    const DisplayCoord dim = dimensions();
     const LineCount line_offset = content_line_offset();
     LineCount line_index = line_offset;
     for (const DisplayLine& line : display_buffer.lines())
     {
         wmove(m_window, (int)line_index, 0);
         wclrtoeol(m_window);
-        draw_line(m_window, line, 0, m_dimensions.column, default_face);
+        draw_line(m_window, line, 0, dim.column, default_face);
         ++line_index;
     }
 
     wbkgdset(m_window, COLOR_PAIR(get_color_pair(padding_face)));
     set_face(m_window, padding_face, default_face);
 
-    while (line_index < m_dimensions.line + line_offset)
+    while (line_index < dim.line + line_offset)
     {
         wmove(m_window, (int)line_index++, 0);
         wclrtoeol(m_window);
@@ -521,7 +516,7 @@ void NCursesUI::check_resize(bool force)
     if (info)
         info_show(m_info.title, m_info.content, m_info.anchor, m_info.face, m_info.style);
 
-    do_ungetch(KEY_RESIZE);
+    set_resize_pending(ResizePending::Yes);
     clearok(curscr, true);
     werase(curscr);
 }
@@ -538,6 +533,14 @@ Optional<Key> NCursesUI::get_next_key()
 
     check_resize();
 
+    if (m_resize_pending != ResizePending::No)
+    {
+        const auto modifiers = (m_resize_pending == ResizePending::OffsetPos) ?
+                               Key::Modifiers::OffsetPos : Key::Modifiers::None;
+        m_resize_pending = ResizePending::No;
+        return resize(dimensions(), modifiers);
+    }
+
     wtimeout(m_window, 0);
     const int c = wgetch(m_window);
     wtimeout(m_window, -1);
@@ -799,7 +802,8 @@ void NCursesUI::menu_show(ConstArrayView<DisplayLine> items,
     m_menu.first_item = 0;
 
     if (style == MenuStyle::Search and previous_height != height)
-        do_ungetch(KEY_RESIZE);
+        set_resize_pending(m_status_on_top ?
+                           ResizePending::OffsetPos : ResizePending::Yes);
 
     draw_menu();
 
@@ -838,7 +842,8 @@ void NCursesUI::menu_hide()
         return;
 
     if (m_menu.style == MenuStyle::Search)
-        do_ungetch(KEY_RESIZE);
+        set_resize_pending(m_status_on_top ?
+                           ResizePending::OffsetPos : ResizePending::Yes);
 
     m_menu.items.clear();
     mark_dirty(m_menu);
@@ -1071,6 +1076,12 @@ LineCount NCursesUI::content_line_offset() const
     return (m_status_on_top ? 1 + (m_menu.style == MenuStyle::Search ? m_menu.size.line : 0) : 0);
 }
 
+void NCursesUI::set_resize_pending(ResizePending resize_pending)
+{
+    m_resize_pending = resize_pending;
+    EventManager::instance().force_signal(0);
+}
+
 void NCursesUI::abort()
 {
     endwin();

src/ncurses_ui.hh

@@ -148,6 +148,11 @@ private:
     bool m_change_colors = true;
 
     bool m_dirty = false;
+
+    enum class ResizePending { No, Yes, OffsetPos };
+    ResizePending m_resize_pending = ResizePending::No;
+
+    void set_resize_pending(ResizePending resize_pending);
 };
 
 }

src/window.cc

@@ -90,7 +90,7 @@ Window::Setup Window::build_setup(const Context& context) const
     for (auto& sel : context.selections())
         selections.push_back({sel.cursor(), sel.anchor()});
 
-    return { m_position, m_dimensions,
+    return { m_position + m_position_offset, m_dimensions,
              context.buffer().timestamp(),
              compute_faces_hash(context.faces()),
              context.selections().main_index(),
@@ -101,7 +101,7 @@ bool Window::needs_redraw(const Context& context) const
 {
     auto& selections = context.selections();
 
-    if (m_position != m_last_setup.position or
+    if (m_position + m_position_offset != m_last_setup.position or
         m_dimensions != m_last_setup.dimensions or
         context.buffer().timestamp() != m_last_setup.timestamp or
         selections.main_index() != m_last_setup.main_selection or
@@ -136,19 +136,16 @@ const DisplayBuffer& Window::update_display_buffer(const Context& context)
     kak_assert(&buffer() == &context.buffer());
     const DisplaySetup setup = compute_display_setup(context);
 
-    m_position = setup.window_pos;
-    m_range = setup.window_range;
-
     const int tabstop = context.options()["tabstop"].get<int>();
-    for (LineCount line = 0; line < m_range.line; ++line)
+    for (LineCount line = 0; line < setup.window_range.line; ++line)
     {
-        LineCount buffer_line = m_position.line + line;
+        LineCount buffer_line = setup.window_pos.line + line;
         if (buffer_line >= buffer().line_count())
             break;
-        auto beg_byte = get_byte_to_column(buffer(), tabstop, {buffer_line, m_position.column});
+        auto beg_byte = get_byte_to_column(buffer(), tabstop, {buffer_line, setup.window_pos.column});
         auto end_byte = setup.full_lines ?
             buffer()[buffer_line].length()
-          : get_byte_to_column(buffer(), tabstop, {buffer_line, m_position.column + m_range.column});
+          : get_byte_to_column(buffer(), tabstop, {buffer_line, setup.window_pos.column + setup.window_range.column});
 
         // The display buffer always has at least one buffer atom, which might be empty if
         // beg_byte == end_byte
@@ -164,6 +161,10 @@ const DisplayBuffer& Window::update_display_buffer(const Context& context)
 
     m_last_setup = build_setup(context);
 
+    m_position.line = clamp(setup.window_pos.line - m_position_offset.line, 0_line, buffer().line_count()-1);
+    m_position.column = std::max(0_col, setup.window_pos.column - m_position_offset.column);
+    m_range = setup.window_range;
+
     if (profile and not (buffer().flags() & Buffer::Flags::Debug))
     {
         using namespace std::chrono;
@@ -181,10 +182,13 @@ void Window::set_position(DisplayCoord position)
     m_position.column = std::max(0_col, position.column);
 }
 
-void Window::set_dimensions(DisplayCoord dimensions)
+void Window::set_dimensions(DisplayCoord dimensions, bool offset_pos)
 {
     if (m_dimensions != dimensions)
     {
+        if (offset_pos)
+            m_position_offset += m_dimensions - dimensions;
+
         m_dimensions = dimensions;
         run_hook_in_own_context("WinResize", format("{}.{}", dimensions.line,
                                                     dimensions.column));
@@ -201,7 +205,7 @@ static void check_display_setup(const DisplaySetup& setup, const Window& window)
 
 DisplaySetup Window::compute_display_setup(const Context& context) const
 {
-    auto win_pos = m_position;
+    auto win_pos = m_position + m_position_offset;
 
     DisplayCoord offset = options()["scrolloff"].get<DisplayCoord>();
     offset.line = std::min(offset.line, (m_dimensions.line + 1) / 2);

src/window.hh

@@ -25,7 +25,7 @@ public:
     const DisplayCoord& range() const { return m_range; }
 
     const DisplayCoord& dimensions() const { return m_dimensions; }
-    void set_dimensions(DisplayCoord dimensions);
+    void set_dimensions(DisplayCoord dimensions, bool offset_pos = false);
 
     void scroll(LineCount offset);
     void center_line(LineCount buffer_line);
@@ -61,6 +61,7 @@ private:
     SafePtr<Client> m_client;
 
     DisplayCoord m_position;
+    DisplayCoord m_position_offset;
     DisplayCoord m_range;
     DisplayCoord m_dimensions;
     DisplayBuffer m_display_buffer;