From 8550049db81453ab2437a562b3d793a8a00f8275 Mon Sep 17 00:00:00 2001
From: Francesco Abbate <francesco.bbt@gmail.com>
Date: Tue, 28 Dec 2021 16:39:40 +0100
Subject: [PATCH] Draw NagView in overlay mode

The NagView takes some actual space in the Y and when it appears
it cause the documents' content to be displaced.

The movement of the documents' content is annoying and should be
avoided so we draw the NagView entirely in overlay mode using defer
draw and we always keep its y size to zero to don't affect the
other application contents.
---
 data/core/nagview.lua | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/data/core/nagview.lua b/data/core/nagview.lua
index 3d448cd4..35ae9b43 100644
--- a/data/core/nagview.lua
+++ b/data/core/nagview.lua
@@ -16,6 +16,7 @@ local NagView = View:extend()
 function NagView:new()
   NagView.super.new(self)
   self.size.y = 0
+  self.show_height = 0
   self.force_focus = false
   self.queue = {}
 end
@@ -50,16 +51,16 @@ function NagView:update()
   NagView.super.update(self)
 
   if core.active_view == self and self.title then
-    self:move_towards(self.size, "y", self:get_target_height())
+    self:move_towards(self, "show_height", self:get_target_height())
     self:move_towards(self, "underline_progress", 1)
   else
-    self:move_towards(self.size, "y", 0)
+    self:move_towards(self, "show_height", 0)
   end
 end
 
-function NagView:draw_overlay()
+function NagView:dim_window_content()
   local ox, oy = self:get_content_offset()
-  oy = oy + self.size.y
+  oy = oy + self.show_height
   local w, h = core.root_view.size.x, core.root_view.size.y - oy
   core.root_view:defer_draw(function()
     renderer.draw_rect(ox, oy, w, h, style.nagbar_dim)
@@ -81,7 +82,7 @@ function NagView:each_option()
     bh = self:get_buttons_height()
     ox,oy = self:get_content_offset()
     ox = ox + self.size.x
-    oy = oy + self.size.y - bh - style.padding.y
+    oy = oy + self.show_height - bh - style.padding.y
 
     for i = #self.options, 1, -1 do
       opt = self.options[i]
@@ -123,19 +124,21 @@ function NagView:on_text_input(text)
 end
 
 
-function NagView:draw()
-  if self.size.y <= 0 or not self.title then return end
+local function draw_nagview_message(self)
+  if self.show_height <= 0 or not self.title then return end
 
-  self:draw_overlay()
-  self:draw_background(style.nagbar)
+  self:dim_window_content()
 
+  -- draw message's background
   local ox, oy = self:get_content_offset()
+  renderer.draw_rect(ox, oy, self.size.x, self.show_height, style.nagbar)
+
   ox = ox + style.padding.x
 
   -- if there are other items, show it
   if #self.queue > 0 then
     local str = string.format("[%d]", #self.queue)
-    ox = common.draw_text(style.font, style.nagbar_text, str, "left", ox, oy, self.size.x, self.size.y)
+    ox = common.draw_text(style.font, style.nagbar_text, str, "left", ox, oy, self.size.x, self.show_height)
     ox = ox + style.padding.x
   end
 
@@ -170,6 +173,10 @@ function NagView:draw()
   end
 end
 
+function NagView:draw()
+  core.root_view:defer_draw(draw_nagview_message, self)
+end
+
 function NagView:get_message_height()
   local h = 0
   for str in string.gmatch(self.message, "(.-)\n") do