Add mouse grab (#1501)

* Add mouse grab

We now also send mouse movement events only to the interested view.

* Add deprecation messages handler

* Make various `View`s respect `on_mouse_left`

* `StatusView`
* `TitleView`
* `TreeView`
* `ToolbarView`

* Fix scrollbar in `TreeView` not updating

We were in some cases sending outdated mouse positions to the scrollbar, 
which made it think that the mouse was hovering it.

This also updates the hovered item more responsively during scroll.

data/core/commands/root.lua

@@ -104,7 +104,7 @@ end, t)
 
 command.add(nil, {
   ["root:scroll"] = function(delta)
-    local view = (core.root_view.overlapping_node and core.root_view.overlapping_node.active_view) or core.active_view
+    local view = core.root_view.overlapping_view or core.active_view
     if view and view.scrollable then
       view.scroll.to.y = view.scroll.to.y + delta * -config.mouse_wheel_scroll
       return true
@@ -112,7 +112,7 @@ command.add(nil, {
     return false
   end,
   ["root:horizontal-scroll"] = function(delta)
-    local view = (core.root_view.overlapping_node and core.root_view.overlapping_node.active_view) or core.active_view
+    local view = core.root_view.overlapping_view or core.active_view
     if view and view.scrollable then
       view.scroll.to.x = view.scroll.to.x + delta * -config.mouse_wheel_scroll
       return true
@@ -154,7 +154,7 @@ command.add(function(node)
 )
 
 command.add(function()
-    local node = core.root_view.overlapping_node
+    local node = core.root_view.root_node:get_child_overlapping_point(core.root_view.mouse.x, core.root_view.mouse.y)
     if not node then return false end
     return (node.hovered_tab or node.hovered_scroll_button > 0) and true, node
   end,

data/core/init.lua

@@ -1490,4 +1490,15 @@ function core.on_error(err)
 end
 
 
+local alerted_deprecations = {}
+---Show deprecation notice once per `kind`.
+---
+---@param kind string
+function core.deprecation_log(kind)
+  if alerted_deprecations[kind] then return end
+  alerted_deprecations[kind] = true
+  core.warn("Used deprecated functionality [%s]. Check if your plugins are up to date.", kind)
+end
+
+
 return core

data/core/node.lua

@@ -18,7 +18,6 @@ function Node:new(type)
   if self.type == "leaf" then
     self:add_view(EmptyView())
   end
-  self.hovered = {x = -1, y = -1 }
   self.hovered_close = 0
   self.tab_shift = 0
   self.tab_offset = 1
@@ -33,9 +32,10 @@ function Node:propagate(fn, ...)
 end
 
 
+---@deprecated
 function Node:on_mouse_moved(x, y, ...)
+  core.deprecation_log("Node:on_mouse_moved")
   if self.type == "leaf" then
-    self.hovered.x, self.hovered.y = x, y
     self.active_view:on_mouse_moved(x, y, ...)
   else
     self:propagate("on_mouse_moved", x, y, ...)
@@ -43,7 +43,9 @@ function Node:on_mouse_moved(x, y, ...)
 end
 
 
+---@deprecated
 function Node:on_mouse_released(...)
+  core.deprecation_log("Node:on_mouse_released")
   if self.type == "leaf" then
     self.active_view:on_mouse_released(...)
   else
@@ -52,7 +54,9 @@ function Node:on_mouse_released(...)
 end
 
 
+---@deprecated
 function Node:on_mouse_left()
+  core.deprecation_log("Node:on_mouse_left")
   if self.type == "leaf" then
     self.active_view:on_mouse_left()
   else
@@ -60,7 +64,10 @@ function Node:on_mouse_left()
   end
 end
 
+
+---@deprecated
 function Node:on_touch_moved(...)
+  core.deprecation_log("Node:on_touch_moved")
   if self.type == "leaf" then
     self.active_view:on_touch_moved(...)
   else
@@ -68,6 +75,7 @@ function Node:on_touch_moved(...)
   end
 end
 
+
 function Node:consume(node)
   for k, _ in pairs(self) do self[k] = nil end
   for k, v in pairs(node) do self[k] = v   end
@@ -489,7 +497,7 @@ function Node:update()
     for _, view in ipairs(self.views) do
       view:update()
     end
-    self:tab_hovered_update(self.hovered.x, self.hovered.y)
+    self:tab_hovered_update(core.root_view.mouse.x, core.root_view.mouse.y)
     local tab_width = self:target_tab_width()
     self:move_towards("tab_shift", tab_width * (self.tab_offset - 1), nil, "tabs")
     self:move_towards("tab_width", tab_width, nil, "tabs")

data/core/rootview.lua

@@ -24,6 +24,9 @@ function RootView:new()
                             base_color = style.drag_overlay_tab,
                             color = { table.unpack(style.drag_overlay_tab) } }
   self.drag_overlay_tab.to = { x = 0, y = 0, w = 0, h = 0 }
+  self.grab = nil -- = {view = nil, button = nil}
+  self.overlapping_view = nil
+  self.touched_view = nil
 end
 
 
@@ -116,6 +119,31 @@ function RootView:close_all_docviews(keep_active)
 end
 
 
+---Obtain mouse grab.
+---
+---This means that mouse movements will be sent to the specified view, even when
+---those occur outside of it.
+---There can't be multiple mouse grabs, even for different buttons.
+---@see RootView:ungrab_mouse
+---@param button core.view.mousebutton
+---@param view core.view
+function RootView:grab_mouse(button, view)
+  assert(self.grab == nil)
+  self.grab = {view = view, button = button}
+end
+
+
+---Release mouse grab.
+---
+---The specified button *must* be the last button that grabbed the mouse.
+---@see RootView:grab_mouse
+---@param button core.view.mousebutton
+function RootView:ungrab_mouse(button)
+  assert(self.grab and self.grab.button == button)
+  self.grab = nil
+end
+
+
 ---Function to intercept mouse pressed events on the active view.
 ---Do nothing by default.
 ---@param button core.view.mousebutton
@@ -132,6 +160,10 @@ end
 ---@param clicks integer
 ---@return boolean
 function RootView:on_mouse_pressed(button, x, y, clicks)
+  -- If there is a grab, release it first
+  if self.grab then
+    self:on_mouse_released(self.grab.button, x, y)
+  end
   local div = self.root_node:get_divider_overlapping_point(x, y)
   local node = self.root_node:get_child_overlapping_point(x, y)
   if div and (node and not node.active_view:scrollbar_overlaps_point(x, y)) then
@@ -156,6 +188,7 @@ function RootView:on_mouse_pressed(button, x, y, clicks)
     end
   elseif not self.dragged_node then -- avoid sending on_mouse_pressed events when dragging tabs
     core.set_active_view(node.active_view)
+    self:grab_mouse(button, node.active_view)
     return self.on_view_mouse_pressed(button, x, y, clicks) or node.active_view:on_mouse_pressed(button, x, y, clicks)
   end
 end
@@ -188,6 +221,21 @@ end
 ---@param x number
 ---@param y number
 function RootView:on_mouse_released(button, x, y, ...)
+  if self.grab then
+    if self.grab.button == button then
+      local grabbed_view = self.grab.view
+      grabbed_view:on_mouse_released(button, x, y, ...)
+      self:ungrab_mouse(button)
+
+      -- If the mouse was released over a different view, send it the mouse position
+      local hovered_view = self.root_node:get_child_overlapping_point(x, y)
+      if grabbed_view ~= hovered_view then
+        self:on_mouse_moved(x, y, 0, 0)
+      end
+    end
+    return
+  end
+
   if self.dragged_divider then
     self.dragged_divider = nil
   end
@@ -228,8 +276,6 @@ function RootView:on_mouse_released(button, x, y, ...)
       end
       self.dragged_node = nil
     end
-  else -- avoid sending on_mouse_released events when dragging tabs
-    self.root_node:on_mouse_released(button, x, y, ...)
   end
 end
 
@@ -250,6 +296,14 @@ end
 ---@param dx number
 ---@param dy number
 function RootView:on_mouse_moved(x, y, dx, dy)
+  self.mouse.x, self.mouse.y = x, y
+
+  if self.grab then
+    self.grab.view:on_mouse_moved(x, y, dx, dy)
+    core.request_cursor(self.grab.view.cursor)
+    return
+  end
+
   if core.active_view == core.nag_view then
     core.request_cursor("arrow")
     core.active_view:on_mouse_moved(x, y, dx, dy)
@@ -269,8 +323,6 @@ function RootView:on_mouse_moved(x, y, dx, dy)
     return
   end
 
-  self.mouse.x, self.mouse.y = x, y
-
   local dn = self.dragged_node
   if dn and not dn.dragging then
     -- start dragging only after enough movement
@@ -283,30 +335,33 @@ function RootView:on_mouse_moved(x, y, dx, dy)
   -- avoid sending on_mouse_moved events when dragging tabs
   if dn then return end
 
-  self.root_node:on_mouse_moved(x, y, dx, dy)
+  local last_overlapping_view = self.overlapping_view
+  local overlapping_node = self.root_node:get_child_overlapping_point(x, y)
+  self.overlapping_view = overlapping_node and overlapping_node.active_view
 
-  local last_overlapping_node = self.overlapping_node
+  if last_overlapping_view and last_overlapping_view ~= self.overlapping_view then
-  self.overlapping_node = self.root_node:get_child_overlapping_point(x, y)
+    last_overlapping_view:on_mouse_left()
-
-  if last_overlapping_node and last_overlapping_node ~= self.overlapping_node then
-    last_overlapping_node:on_mouse_left()
   end
-  if not self.overlapping_node then return end
+
+  if not self.overlapping_view then return end
+
+  self.overlapping_view:on_mouse_moved(x, y, dx, dy)
+  core.request_cursor(self.overlapping_view.cursor)
+
+  if not overlapping_node then return end
 
   local div = self.root_node:get_divider_overlapping_point(x, y)
-  if self.overlapping_node:get_scroll_button_index(x, y) or self.overlapping_node:is_in_tab_area(x, y) then
+  if overlapping_node:get_scroll_button_index(x, y) or overlapping_node:is_in_tab_area(x, y) then
     core.request_cursor("arrow")
-  elseif div and not self.overlapping_node.active_view:scrollbar_overlaps_point(x, y) then
+  elseif div and not self.overlapping_view:scrollbar_overlaps_point(x, y) then
     core.request_cursor(div.type == "hsplit" and "sizeh" or "sizev")
-  else
-    core.request_cursor(self.overlapping_node.active_view.cursor)
   end
 end
 
 
 function RootView:on_mouse_left()
-  if self.overlapping_node then
+  if self.overlapping_view then
-    self.overlapping_node:on_mouse_left()
+    self.overlapping_view:on_mouse_left()
   end
 end
 
@@ -333,15 +388,16 @@ function RootView:on_text_input(...)
 end
 
 function RootView:on_touch_pressed(x, y, ...)
-  self.touched_node = self.root_node:get_child_overlapping_point(x, y)
+  local touched_node = self.root_node:get_child_overlapping_point(x, y)
+  self.touched_view = touched_node and touched_node.active_view
 end
 
 function RootView:on_touch_released(x, y, ...)
-  self.touched_node = nil
+  self.touched_view = nil
 end
 
 function RootView:on_touch_moved(x, y, dx, dy, ...)
-  if not self.touched_node then return end
+  if not self.touched_view then return end
   if core.active_view == core.nag_view then
     core.active_view:on_touch_moved(x, y, dx, dy, ...)
     return
@@ -372,7 +428,7 @@ function RootView:on_touch_moved(x, y, dx, dy, ...)
   -- avoid sending on_touch_moved events when dragging tabs
   if dn then return end
 
-  self.touched_node:on_touch_moved(x, y, dx, dy, ...)
+  self.touched_view:on_touch_moved(x, y, dx, dy, ...)
 end
 
 function RootView:on_ime_text_editing(...)

data/core/statusview.lua

@@ -989,6 +989,12 @@ function StatusView:on_mouse_pressed(button, x, y, clicks)
 end
 
 
+function StatusView:on_mouse_left()
+  StatusView.super.on_mouse_left(self)
+  self.hovered_item = {}
+end
+
+
 function StatusView:on_mouse_moved(x, y, dx, dy)
   if not self.visible then return end
   StatusView.super.on_mouse_moved(self, x, y, dx, dy)

data/core/titleview.lua

@@ -112,6 +112,12 @@ function TitleView:on_mouse_pressed(button, x, y, clicks)
 end
 
 
+function TitleView:on_mouse_left()
+  TitleView.super.on_mouse_left(self)
+  self.hovered_item = nil
+end
+
+
 function TitleView:on_mouse_moved(px, py, ...)
   if self.size.y == 0 then return end
   TitleView.super.on_mouse_moved(self, px, py, ...)

data/plugins/toolbarview.lua

@@ -100,6 +100,16 @@ function ToolbarView:on_mouse_pressed(button, x, y, clicks)
 end
 
 
+function ToolbarView:on_mouse_left()
+  ToolbarView.super.on_mouse_left(self)
+  if self.tooltip then
+    core.status_view:remove_tooltip()
+    self.tooltip = false
+  end
+  self.hovered_item = nil
+end
+
+
 function ToolbarView:on_mouse_moved(px, py, ...)
   if not self.visible then return end
   ToolbarView.super.on_mouse_moved(self, px, py, ...)

data/plugins/treeview.lua

@@ -51,7 +51,7 @@ function TreeView:new()
   self.target_size = config.plugins.treeview.size
   self.cache = {}
   self.tooltip = { x = 0, y = 0, begin = 0, alpha = 0 }
-  self.cursor_pos = { x = 0, y = 0 }
+  self.last_scroll_y = 0
 
   self.item_icon_width = 0
   self.item_text_spacing = 0
@@ -251,10 +251,9 @@ function TreeView:get_text_bounding_box(item, x, y, w, h)
 end
 
 
+
 function TreeView:on_mouse_moved(px, py, ...)
   if not self.visible then return end
-  self.cursor_pos.x = px
-  self.cursor_pos.y = py
   if TreeView.super.on_mouse_moved(self, px, py, ...) then
     -- mouse movement handled by the View (scrollbar)
     self.hovered_item = nil
@@ -281,6 +280,12 @@ function TreeView:on_mouse_moved(px, py, ...)
 end
 
 
+function TreeView:on_mouse_left()
+  TreeView.super.on_mouse_left(self)
+  self.hovered_item = nil
+end
+
+
 function TreeView:update()
   -- update width
   local dest = self.visible and self.target_size or 0
@@ -304,10 +309,10 @@ function TreeView:update()
   self.item_text_spacing = style.icon_font:get_width("f") / 2
 
   -- this will make sure hovered_item is updated
-  -- we don't want events when the thing is scrolling fast
+  local dy = math.abs(self.last_scroll_y - self.scroll.y)
-  local dy = math.abs(self.scroll.to.y - self.scroll.y)
+  if dy > 0 then
-  if self.scroll.to.y ~= 0 and dy < self:get_item_height() then
+    self:on_mouse_moved(core.root_view.mouse.x, core.root_view.mouse.y, 0, 0)
-    self:on_mouse_moved(self.cursor_pos.x, self.cursor_pos.y, 0, 0)
+    self.last_scroll_y = self.scroll.y
   end
 
   local config = config.plugins.treeview
@@ -751,7 +756,7 @@ command.add(
 
   ["treeview-context:show"] = function()
     if view.hovered_item then
-      menu:show(view.cursor_pos.x, view.cursor_pos.y)
+      menu:show(core.root_view.mouse.x, core.root_view.mouse.y)
       return
     end