Add cursor animations

Looks pretty nice. No fancy effects like Neovide but the cursor's
movement is animated. Frametimes / framerate is controllable with
:NvuiCursorFrametime {ms}, duration controllable with
:NvuiCursorAnimationDuration {seconds}, and the scaler is controllable
with :NvuiCursorScaler {scaler}. Also added the documentation for these
commands.
This has also alerted me to deficiencies in the move and scroll
animations, particularly the scroll animation, that is caused by the
timer reset.

src/cursor.cpp

@@ -1,6 +1,12 @@
 #include "cursor.hpp"
+#include "editor.hpp"
+#include "grid.hpp"
 #include <fmt/core.h>
 #include <fmt/format.h>
+
+using scalers::time_scaler;
+time_scaler Cursor::animation_scaler = scalers::oneminusexpo2negative10;
+
 Cursor::Cursor()
   : blinkwait_timer(nullptr),
     blinkon_timer(nullptr),
@@ -24,6 +30,35 @@ Cursor::Cursor()
   });
 }
 
+Cursor::Cursor(EditorArea* ea)
+  : Cursor()
+{
+  assert(editor_area);
+  editor_area = ea;
+  cursor_animation_timer.callOnTimeout([this] {
+    auto interval = cursor_animation_timer.interval();
+    cursor_animation_time -= static_cast<float>(interval) / 1000.f;
+    if (cursor_animation_time <= 0.f)
+    {
+      cursor_animation_timer.stop();
+      cur_x = destination_x;
+      cur_y = destination_y;
+    }
+    else
+    {
+      auto x_diff = destination_x - old_x;
+      auto y_diff = destination_y - old_y;
+      auto duration = editor_area->cursor_animation_duration();
+      auto animation_left = cursor_animation_time / duration;
+      float animation_finished = 1.0f - animation_left;
+      float scaled = animation_scaler(animation_finished);
+      cur_x = old_x + (x_diff * scaled);
+      cur_y = old_y + (y_diff * scaled);
+    }
+    editor_area->update();
+  });
+}
+
 void Cursor::mode_change(const msgpack::object* obj, std::uint32_t size)
 {
   assert(obj->type == msgpack::type::ARRAY);
@@ -170,13 +205,41 @@ void Cursor::show() noexcept
 void Cursor::go_to(CursorPos pos)
 {
   prev_pos = cur_pos;
-  cur_pos = pos;
+  if (!use_animated_position())
+  {
+    cursor_animation_timer.stop();
+    cur_pos = pos;
+  }
+  else
+  {
+    cur_pos = pos;
+    old_x = cur_x;
+    old_y = cur_y;
+    destination_x = cur_pos->grid_x + cur_pos->col;
+    destination_y = cur_pos->grid_y + cur_pos->row;
+    cursor_animation_time = editor_area->cursor_animation_duration();
+    auto interval = editor_area->cursor_animation_frametime();
+    if (cursor_animation_timer.interval() != interval)
+    {
+      cursor_animation_timer.setInterval(interval);
+    }
+    if (!cursor_animation_timer.isActive()) cursor_animation_timer.start();
+  }
   reset_timers();
 }
 
 /// Returns a CursorRect containing the cursor rectangle
 /// in pixels, based on the row, column, font width, and font height.
-static CursorRect get_rect(const ModeInfo& mode, int row, int col, float font_width, float font_height, float caret_extend_top, float caret_extend_bottom, float scale = 1.0f)
+static CursorRect get_rect(
+  const ModeInfo& mode,
+  float row,
+  float col,
+  float font_width,
+  float font_height,
+  float caret_extend_top,
+  float caret_extend_bottom,
+  float scale = 1.0f
+)
 {
   // These do nothing for now
   bool should_draw_text = mode.cursor_shape == CursorShape::Block;
@@ -214,10 +277,17 @@ static CursorRect get_rect(const ModeInfo& mode, int row, int col, float font_wi
 std::optional<CursorRect> Cursor::rect(float font_width, float font_height, float scale) const noexcept
 {
   if (!cur_pos.has_value()) return std::nullopt;
+  float x = cur_pos->grid_x + cur_pos->col;
+  float y = cur_pos->grid_y + cur_pos->row;
+  if (use_animated_position())
+  {
+    x = cur_x;
+    y = cur_y;
+  }
   return get_rect(
     cur_mode,
-    cur_pos->grid_y + cur_pos->row,
-    cur_pos->grid_x + cur_pos->col,
+    y,
+    x,
     font_width, font_height,
     caret_extend_top,
     caret_extend_bottom,
@@ -252,3 +322,10 @@ void Cursor::busy_stop()
   status = CursorStatus::Visible;
   reset_timers();
 }
+
+bool Cursor::use_animated_position() const
+{
+  return editor_area
+      && editor_area->animations_enabled()
+      && editor_area->cursor_animation_frametime() > 0;
+}

src/cursor.hpp

@@ -5,6 +5,7 @@
 #include <cstdint>
 #include <msgpack.hpp>
 #include "hlstate.hpp"
+#include "grid.hpp"
 
 enum class CursorShape : std::uint8_t
 {
@@ -56,12 +57,15 @@ struct ModeInfo
   // (mouse_shape)
 };
 
+class EditorArea;
 /// The Cursor class stores the data for the Neovim cursor
 class Cursor : public QObject
 {
   Q_OBJECT
 public:
+  static scalers::time_scaler animation_scaler;
   Cursor();
+  Cursor(EditorArea* editor_area);
   /**
    * Handles a 'mode_info_set' Neovim redraw event.
    */
@@ -132,6 +136,7 @@ class Cursor : public QObject
     caret_extend_bottom = bottom;
   }
 private:
+  EditorArea* editor_area = nullptr;
   float caret_extend_top = 0.f;
   float caret_extend_bottom = 0.f;
   int cell_width;
@@ -150,6 +155,15 @@ class Cursor : public QObject
   std::size_t old_mode_idx;
   float old_mode_scale = 1.0f;
   std::string cur_mode_name;
+  float cursor_animation_time;
+  // These x and y are in terms of text, not pixels
+  float cur_x = 0.f;
+  float cur_y = 0.f;
+  float old_x = 0.f;
+  float old_y = 0.f;
+  float destination_x = 0.f;
+  float destination_y = 0.f;
+  QTimer cursor_animation_timer {};
 signals:
   void cursor_visible();
   void cursor_hidden();
@@ -187,6 +201,7 @@ class Cursor : public QObject
   {
     return status == CursorStatus::Busy;
   }
+  bool use_animated_position() const;
 };
 
 #endif // NVUI_CURSOR_HPP

src/editor.cpp

@@ -75,7 +75,7 @@ EditorArea::EditorArea(QWidget* parent, HLState* hl_state, Nvim* nv)
   state(hl_state),
   nvim(nv),
   pixmap(width(), height()),
-  neovim_cursor(),
+  neovim_cursor(this),
   popup_menu(hl_state, this),
   cmdline(hl_state, &neovim_cursor, this)
 {

src/editor.hpp

@@ -309,6 +309,13 @@ class EditorArea : public QWidget
       GridBase::scroll_scaler = scalers::scalers().at(scaler);
     }
   }
+  void set_cursor_scaler(std::string scaler)
+  {
+    if (scalers::scalers().contains(scaler))
+    {
+      Cursor::animation_scaler = scalers::scalers().at(scaler);
+    }
+  }
   void set_scroll_animation_duration(float dur)
   {
     if (dur > 0.f) scroll_animation_time = dur;
@@ -329,6 +336,22 @@ class EditorArea : public QWidget
   {
     popup_menu.info_display().set_cols(columns);
   }
+  float cursor_animation_duration() const
+  {
+    return cursor_animation_time;
+  }
+  int cursor_animation_frametime() const
+  {
+    return cursor_animation_frametime_ms;
+  }
+  void set_cursor_frametime(int ms)
+  {
+    cursor_animation_frametime_ms = ms;
+  }
+  void set_cursor_animation_duration(float secs)
+  {
+    cursor_animation_time = secs;
+  }
   /// For input methods
   virtual QVariant inputMethodQuery(Qt::InputMethodQuery) const override;
 protected:
@@ -364,6 +387,8 @@ class EditorArea : public QWidget
   int animation_frame_interval_ms = 10;
   int scroll_animation_frame_interval = 10;
   float scroll_animation_time = 0.3f;
+  float cursor_animation_time = 0.3f;
+  int cursor_animation_frametime_ms = 10;
   /**
    * Sets the current font to new_font.
    */

src/window.cpp

@@ -583,6 +583,18 @@ void Window::register_handlers()
     if (b) enable_frameless_window();
     else disable_frameless_window();
   }));
+  listen_for_notification("NVUI_CURSOR_SCALER",
+    paramify<std::string>([this](std::string scaler) {
+      editor_area.set_cursor_scaler(scaler);
+  }));
+  listen_for_notification("NVUI_CURSOR_ANIMATION_DURATION",
+    paramify<float>([this](float s) {
+      editor_area.set_cursor_animation_duration(s);
+  }));
+  listen_for_notification("NVUI_CURSOR_FRAMETIME",
+    paramify<int>([this](int ms) {
+      editor_area.set_cursor_frametime(ms);
+  }));
   /// Add request handlers
   using arr = msgpack::object_array;
   handle_request<std::vector<std::string>, std::string>(

vim/doc/nvui.txt

@@ -11,6 +11,7 @@ Titlebar			|nvui-titlebar|
 Popup					|nvui-popup|
 Cmdline				|nvui-cmdline|
 Multigrid			|nvui-multigrid|
+Cursor				|nvui-cursor|
 ==============================================================================
 COMMANDS			*nvui-commands*
 
@@ -374,4 +375,37 @@ through commands.
 	To get the corresponding framerate divide 1000 by {msperframe}.
 
 ==============================================================================
+CURSOR					*nvui-cursor*
+The cursor is pretty simple. There is an animation for the cursor when it
+moves, and some commands to customize the animation.
+
+:NvuiCursorScaler {scaler}				*:NvuiCursorScaler*
+
+	Changes the animation scaler to {scaler}.
+	For a description of how the animation scalers work, look at
+	|:NvuiMoveScaler| and |:NvuiScrollScaler|.
+	There is a completion list of the available scaler functions, any other
+	input will do nothing.
+	Ex. :NvuiCursorScaler identity
+	Uses the "identity" scaler (t => t) to process the animation. The cursor
+	travels at a constant speed.
+
+:NvuiCursorAnimationDuration {seconds}				*:NvuiCursorAnimationDuration*
+
+	Change the animation duration to {seconds}. This is how long the cursor
+	takes to move from one point to the other.
+	Ex. :NvuiCursorAnimationDuration 2.0
+	The cursor takes 2.0 seconds to move from one point to another.
+
+:NvuiCursorFrametime {ms}					*:NvuiCursorFrametime*
+
+	{ms} must be an integer. If the value of {ms} is less than or equal to 0,
+	the animation is disabled.
+	Changes the frametime of the cursor animation.
+	To get the framerate, divide 1000 by {ms}.
+	Ex. :NvuiCursorFrametime 10
+	Sets the animation to update every 10ms (100fps). Of course this is only if
+	the frames are able to render in the correct amount of time.
+	:NvuiCursorFrametime -1 will disable the animations.
+==============================================================================
 vim:ft=help:textwidth=78:ts=2:noet

vim/doc/tags

@@ -12,6 +12,9 @@
 :NvuiCmdPadding	nvui.txt	/*:NvuiCmdPadding*
 :NvuiCmdTopPos	nvui.txt	/*:NvuiCmdTopPos*
 :NvuiCmdWidth	nvui.txt	/*:NvuiCmdWidth*
+:NvuiCursorAnimationDuration	nvui.txt	/*:NvuiCursorAnimationDuration*
+:NvuiCursorFrametime	nvui.txt	/*:NvuiCursorFrametime*
+:NvuiCursorScaler	nvui.txt	/*:NvuiCursorScaler*
 :NvuiFrameless	nvui.txt	/*:NvuiFrameless*
 :NvuiFullscreen	nvui.txt	/*:NvuiFullscreen*
 :NvuiMoveAnimationDuration	nvui.txt	/*:NvuiMoveAnimationDuration*
@@ -46,6 +49,7 @@
 :NvuiToggleFullscreen	nvui.txt	/*:NvuiToggleFullscreen*
 nvui-cmdline	nvui.txt	/*nvui-cmdline*
 nvui-commands	nvui.txt	/*nvui-commands*
+nvui-cursor	nvui.txt	/*nvui-cursor*
 nvui-general	nvui.txt	/*nvui-general*
 nvui-multigrid	nvui.txt	/*nvui-multigrid*
 nvui-popup	nvui.txt	/*nvui-popup*

vim/plugin/nvui.vim

@@ -13,6 +13,7 @@ command! -nargs=1 NvuiSnapshotLimit call rpcnotify(1, 'NVUI_SNAPSHOT_LIMIT', <ar
 command! -nargs=1 NvuiScrollFrametime call rpcnotify(1, 'NVUI_SCROLL_FRAMETIME', <args>)
 command! -nargs=1 -complete=customlist,s:complete_scaler NvuiScrollScaler call NvuiNotify('NVUI_SCROLL_SCALER', <f-args>)
 command! -nargs=1 -complete=customlist,s:complete_scaler NvuiMoveScaler call NvuiNotify('NVUI_MOVE_SCALER', <f-args>)
+command! -nargs=1 -complete=customlist,s:complete_scaler NvuiCursorScaler call NvuiNotify('NVUI_CURSOR_SCALER', <f-args>)
 command! -nargs=1 NvuiMoveAnimationFrametime call rpcnotify(1, 'NVUI_ANIMATION_FRAMETIME', <args>)
 command! -nargs=1 NvuiAnimationsEnabled call rpcnotify(1, 'NVUI_ANIMATIONS_ENABLED', <args>)
 command! -nargs=1 NvuiMoveAnimationDuration call rpcnotify(1, 'NVUI_MOVE_ANIMATION_DURATION', <args>)
@@ -58,5 +59,7 @@ command! -nargs=1 NvuiCharspace call rpcnotify(1, 'NVUI_CHARSPACE', <args>)
 command! -nargs=1 NvuiFullscreen call rpcnotify(1, 'NVUI_FULLSCREEN', <args>)
 command! NvuiToggleFullscreen call rpcnotify(1, 'NVUI_TOGGLE_FULLSCREEN')
 command! -nargs=1 NvuiFrameless call rpcnotify(1, 'NVUI_FRAMELESS', <args>)
+command! -nargs=1 NvuiCursorAnimationDuration call rpcnotify(1, 'NVUI_CURSOR_ANIMATION_DURATION', <args>)
+command! -nargs=1 NvuiCursorFrametime call rpcnotify(1, 'NVUI_CURSOR_FRAMETIME', <args>)
 autocmd BufEnter * call rpcnotify(1, 'NVUI_BUFENTER', expand('%:t'))
 autocmd DirChanged * call rpcnotify(1, 'NVUI_DIRCHANGED', fnamemodify(getcwd(), ':t'), getcwd())