From 80e25dbfd361b4adca715c6d1ae55499075c50b2 Mon Sep 17 00:00:00 2001
From: Francesco Abbate <francesco.bbt@gmail.com>
Date: Sun, 5 Sep 2021 18:44:55 +0200
Subject: [PATCH] Use drawing_cache without disable mechanism

---
 data/core/docview.lua  | 66 +++++++++++++++++++++++++-----------------
 data/core/rootview.lua |  1 +
 data/plugins/scale.lua |  2 ++
 3 files changed, 42 insertions(+), 27 deletions(-)

diff --git a/data/core/docview.lua b/data/core/docview.lua
index b3db2138..a969c842 100644
--- a/data/core/docview.lua
+++ b/data/core/docview.lua
@@ -56,7 +56,7 @@ function DocView:new(doc)
   self.doc = assert(doc)
   self.font = "code_font"
   self.last_x_offset = {}
-  self.step_cache = {}
+  self.drawing_cache = {}
 end
 
 
@@ -98,38 +98,51 @@ function DocView:get_filename()
 end
 
 
-function DocView:get_scrollable_size()
-  if self.step_cache.enabled and self.step_cache.scrollable_size ~= nil then
-    return self.step_cache.scrollable_size
-  end
-  self.step_cache.scrollable_size = self:get_line_height() * (#self.doc.lines - 1) + self.size.y
-  return self.step_cache.scrollable_size
+function DocView:compute_scrollable_size()
+  return self:get_line_height() * (#self.doc.lines - 1) + self.size.y
 end
 
-function DocView:get_h_scrollable_size()
-  if self.step_cache.enabled and self.step_cache.h_scrollable_size ~= nil then
-    return self.step_cache.h_scrollable_size
-  end
+
+function DocView:get_scrollable_size()
+  return self.drawing_cache.scrollable_size
+end
+
+
+function DocView:compute_h_scrollable_size()
   local xmargin = 3 * self:get_font():get_width(' ') -- from DocView:scroll_to_make_visible
   local long_line = next(self.doc.long_lines.line_numbers) or 1
-  self.step_cache.h_scrollable_size = self:get_col_x_offset(long_line, self.doc.long_lines.length)
-                                      + self:get_gutter_width() + xmargin
-  return self.step_cache.h_scrollable_size
+  return self:get_col_x_offset(long_line, self.doc.long_lines.length) + self:get_gutter_width() + xmargin
 end
 
+
+function DocView:get_h_scrollable_size()
+  return self.drawing_cache.h_scrollable_size
+end
+
+
 function DocView:get_font()
   return style[self.font]
 end
 
 
-function DocView:get_line_height()
+function DocView:compute_line_height()
   return math.floor(self:get_font():get_height() * config.line_height)
 end
 
 
+function DocView:get_line_height()
+  return self.drawing_cache.line_height
+end
+
+
+function DocView:compute_gutter_width()
+  return self:get_font():get_width(#self.doc.lines)
+end
+
+
 function DocView:get_gutter_width()
   local padding = style.padding.x * 2
-  return self:get_font():get_width(#self.doc.lines) + padding, padding
+  return self.drawing_cache.gutter_width + padding, padding
 end
 
 
@@ -285,7 +298,6 @@ end
 
 
 function DocView:on_mouse_moved(x, y, ...)
-  self.step_cache.enabled = true
   DocView.super.on_mouse_moved(self, x, y, ...)
 
   if self:scrollbar_overlaps_point(x, y) or self.dragging_scrollbar
@@ -309,7 +321,6 @@ function DocView:on_mouse_moved(x, y, ...)
       self.doc:set_selection(mouse_selection(self.doc, clicks, l1, c1, l2, c2))
     end
   end
-  self.step_cache.enabled = false
 end
 
 
@@ -323,14 +334,9 @@ function DocView:on_text_input(text)
   self.doc:text_input(text)
 end
 
-function DocView:invalidate_step_cache()
-  self.step_cache.scrollable_size = nil
-  self.step_cache.h_scrollable_size = nil
-end
 
 function DocView:update()
-  self:invalidate_step_cache()
-  self.step_cache.enabled = true
+  self:update_drawing_cache()
   -- scroll to make caret visible and reset blink timer if it moved
   local line, col = self.doc:get_selection()
   if (line ~= self.last_line or col ~= self.last_col) and self.size.x > 0 then
@@ -352,7 +358,6 @@ function DocView:update()
   end
 
   DocView.super.update(self)
-  self.step_cache.enabled = false
 end
 
 
@@ -443,7 +448,6 @@ function DocView:draw_overlay()
 end
 
 function DocView:draw()
-  self.step_cache.enabled = true
   self:draw_background(style.background)
 
   self:get_font():set_tab_size(config.indent_size)
@@ -470,7 +474,15 @@ function DocView:draw()
 
   self:draw_scrollbar()
   self:draw_h_scrollbar()
-  self.step_cache.enabled = false
+end
+
+
+function DocView:update_drawing_cache()
+  local cache = self.drawing_cache
+  cache.gutter_width      = self:compute_gutter_width()
+  cache.line_height       = self:compute_line_height()
+  cache.scrollable_size   = self:compute_scrollable_size()
+  cache.h_scrollable_size = self:compute_h_scrollable_size()
 end
 
 
diff --git a/data/core/rootview.lua b/data/core/rootview.lua
index 9d017268..12408428 100644
--- a/data/core/rootview.lua
+++ b/data/core/rootview.lua
@@ -754,6 +754,7 @@ function RootView:open_doc(doc)
   local view = DocView(doc)
   node:add_view(view)
   self.root_node:update_layout()
+  view:update_drawing_cache()
   view:scroll_to_line(view.doc:get_selection(), true, true)
   return view
 end
diff --git a/data/plugins/scale.lua b/data/plugins/scale.lua
index 8d16304b..04e67a95 100644
--- a/data/plugins/scale.lua
+++ b/data/plugins/scale.lua
@@ -56,6 +56,8 @@ local function set_scale(scale)
     renderer.font.set_size(style.code_font, s * style.code_font:get_size())
   end
 
+  view:update_drawing_cache()
+
   -- restore scroll positions
   for view, n in pairs(scrolls) do
     view.scroll.y = n * (view:get_scrollable_size() - view.size.y)