Add smooth caret plugin for lite-xl

.config/lite-xl/plugins/smoothcaret.lua

@@ -0,0 +1,116 @@
+-- mod-version:3
+local core = require "core"
+local config = require "core.config"
+local style = require "core.style"
+local common = require "core.common"
+local DocView = require "core.docview"
+
+config.plugins.smoothcaret = common.merge({
+  enabled = true,
+  rate = 0.65,
+  -- The config specification used by the settings gui
+  config_spec = {
+    name = "Smooth Caret",
+    {
+      label = "Enabled",
+      description = "Disable or enable the smooth caret animation.",
+      path = "enabled",
+      type = "toggle",
+      default = true
+    },
+    {
+      label = "Rate",
+      description = "Speed of the animation.",
+      path = "rate",
+      type = "number",
+      default = 0.65,
+      min = 0.2,
+      max = 1.0,
+      step = 0.05
+    },
+  }
+}, config.plugins.smoothcaret)
+
+local docview_update = DocView.update
+function DocView:update()
+  docview_update(self)
+
+  if not config.plugins.smoothcaret.enabled then return end
+
+  local minline, maxline = self:get_visible_line_range()
+
+  -- We need to keep track of all the carets
+  if not self.carets then
+    self.carets = { }
+  end
+  -- and we need the list of visible ones that `DocView:draw_caret` will use in succession
+  self.visible_carets = { }
+
+  local idx, v_idx = 1, 1
+  for _, line, col in self.doc:get_selections() do
+    local x, y = self:get_line_screen_position(line, col)
+    -- Keep the position relative to the whole View
+    -- This way scrolling won't animate the caret
+    x = x + self.scroll.x
+    y = y + self.scroll.y
+
+    if not self.carets[idx] then
+      self.carets[idx] = { current = { x = x, y = y }, target = { x = x, y = y } }
+    end
+
+    local c = self.carets[idx]
+    c.target.x = x
+    c.target.y = y
+
+    -- Chech if the number of carets changed
+    if self.last_n_selections ~= #self.doc.selections then
+      -- Don't animate when there are new carets
+      c.current.x = x
+      c.current.y = y
+    else
+      self:move_towards(c.current, "x", c.target.x, config.plugins.smoothcaret.rate)
+      self:move_towards(c.current, "y", c.target.y, config.plugins.smoothcaret.rate)
+    end
+
+    -- Keep track of visible carets
+    if line >= minline and line <= maxline then
+      self.visible_carets[v_idx] = self.carets[idx]
+      v_idx = v_idx + 1
+    end
+    idx = idx + 1
+  end
+  self.last_n_selections = #self.doc.selections
+
+  -- Remove unused carets to avoid animating new ones when they are added
+  for i = idx, #self.carets do
+    self.carets[i] = nil
+  end
+
+  if self.mouse_selecting ~= self.last_mouse_selecting then
+    self.last_mouse_selecting = self.mouse_selecting
+    -- Show the caret on click, so that it can be seen moving towards the new position
+    if self.mouse_selecting then
+      core.blink_timer = core.blink_timer + config.blink_period / 2
+      core.redraw = true
+    end
+  end
+
+  -- This is used by `DocView:draw_caret` to keep track of the current caret
+  self.caret_idx = 1
+end
+
+local docview_draw_caret = DocView.draw_caret
+function DocView:draw_caret(x, y)
+  if not config.plugins.smoothcaret.enabled then
+    docview_draw_caret(self, x, y)
+    return
+  end
+
+  local c = self.visible_carets[self.caret_idx] or { current = { x = x, y = y } }
+  local lh = self:get_line_height()
+
+  -- We use the scroll position to move back to the position relative to the window
+  renderer.draw_rect(c.current.x - self.scroll.x, c.current.y - self.scroll.y, style.caret_width, lh, style.caret)
+
+  self.caret_idx = self.caret_idx + 1
+end