From 00f1513a1c11bab7e4ac194628fb33b522fe2176 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Thu, 25 Feb 2021 16:40:20 +0100
Subject: pager: granular page modification

Do not rebuild the entire page each time the client list changes,
add/remove clients individually.
---
 pager.lua | 87 ++++++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 50 insertions(+), 37 deletions(-)

(limited to 'pager.lua')

diff --git a/pager.lua b/pager.lua
index 985122d..f4d3054 100644
--- a/pager.lua
+++ b/pager.lua
@@ -20,41 +20,48 @@ function Page:set_visible(visible, this_screen)
     self.border:set_color(border_color)
 end
 
-function Page:update()
+function Page:client_remove(client)
+    wgt = self._widgets[client]
+    if wgt then
+        self.client_container:remove_widgets(wgt)
+    end
+
+    self._widgets[client] = nil
+end
+
+function Page:client_add(client)
     local font = beautiful.small_text_font or "sans 7"
 
-    self.client_container:reset()
-    for i, client in pairs(self.tag:clients()) do
-        local text     = client.name
-
-        local bg_normal = beautiful.bg_normal or "#000000"
-        local fg_normal = beautiful.fg_normal or "#ffffff"
-        local bg_focus  = beautiful.bg_focus  or "#ffffff"
-        local fg_focus  = beautiful.fg_focus  or "#000000"
-
-        local tb       = wibox.widget.textbox(text, true)
-        local bg       = wibox.container.background(tb, bg)
-
-        tb:set_font(font)
-
-        client:connect_signal("property::name", function() tb:set_text(client.name or "") end)
-        client:connect_signal("focus",
-            function(c)
-                if c.screen == self.screen then
-                    bg:set_bg(bg_focus)
-                    bg:set_fg(fg_focus)
-                end
-            end)
-        client:connect_signal("unfocus",
-            function(c)
-                if c.screen == self.screen then
-                    bg:set_bg(bg_normal)
-                    bg:set_fg(fg_normal)
-                end
-            end)
-
-        self.client_container:add(bg)
-    end
+    local text     = client.name
+
+    local bg_normal = beautiful.bg_normal or "#000000"
+    local fg_normal = beautiful.fg_normal or "#ffffff"
+    local bg_focus  = beautiful.bg_focus  or "#ffffff"
+    local fg_focus  = beautiful.fg_focus  or "#000000"
+
+    local tb       = wibox.widget.textbox(text, true)
+    local bg       = wibox.container.background(tb, bg)
+
+    tb:set_font(font)
+
+    client:connect_signal("property::name", function() tb:set_text(client.name or "") end)
+    client:connect_signal("focus",
+        function(c)
+            if c.screen == self.screen then
+                bg:set_bg(bg_focus)
+                bg:set_fg(fg_focus)
+            end
+        end)
+    client:connect_signal("unfocus",
+        function(c)
+            if c.screen == self.screen then
+                bg:set_bg(bg_normal)
+                bg:set_fg(fg_normal)
+            end
+        end)
+
+    self.client_container:add(bg)
+    self._widgets[client] = bg
 end
 
 function Page:new(tag, width, height, screen)
@@ -74,12 +81,18 @@ function Page:new(tag, width, height, screen)
     ret.border           = margin
     ret.tag              = tag
     ret.screen           = screen
+    -- a table of mapping clients to their widgets
+    ret._widgets         = {}
 
-    tag:connect_signal('tagged',   function (c) ret:update() end)
-    tag:connect_signal('untagged', function (c) ret:update() end)
+    ret:set_visible(tag.selected, tag.screen == screen)
+
+    -- add initial clients
+    for i, client in pairs(tag:clients()) do
+        ret:client_add(client)
+    end
 
-    ret:set_visible(false, false)
-    ret:update()
+    tag:connect_signal('tagged',   function (t, c) ret:client_add(c) end)
+    tag:connect_signal('untagged', function (t, c) ret:client_remove(c) end)
 
     return ret
 end
-- 
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