From 03663fe778794c2e4229a4d03a0bd24060f3b6a0 Mon Sep 17 00:00:00 2001
From: kindlycat <grishkokot@gmail.com>
Date: Wed, 12 Aug 2015 22:31:06 +0000
Subject: [PATCH] Add "opacity" property for widgets

---
 lib/wibox/drawable.lua    | 3 +++
 lib/wibox/layout/base.lua | 3 +++
 lib/wibox/widget/base.lua | 9 +++++++++
 3 files changed, 15 insertions(+)

diff --git a/lib/wibox/drawable.lua b/lib/wibox/drawable.lua
index c9d0a483..3f05df9b 100644
--- a/lib/wibox/drawable.lua
+++ b/lib/wibox/drawable.lua
@@ -59,7 +59,10 @@ local function do_redraw(self)
     self._widget_geometries = {}
     if self.widget and self.widget.visible then
         cr:set_source(self.foreground_color)
+        cr:push_group()
         self.widget:draw(self.widget_arg, cr, width, height)
+        cr:pop_group_to_source()
+        cr:paint_with_alpha(self.widget.opacity)
         self:widget_at(self.widget, 0, 0, width, height)
     end
 
diff --git a/lib/wibox/layout/base.lua b/lib/wibox/layout/base.lua
index 97e93966..3b85c2e1 100644
--- a/lib/wibox/layout/base.lua
+++ b/lib/wibox/layout/base.lua
@@ -66,11 +66,14 @@ function base.draw_widget(wibox, cr, widget, x, y, width, height)
     cr:rectangle(0, 0, width, height)
     cr:clip()
 
+    cr:push_group()
     -- Let the widget draw itself
     local success, msg = pcall(widget.draw, widget, wibox, cr, width, height)
     if not success then
         print("Error while drawing widget: " .. msg)
     end
+    cr:pop_group_to_source()
+    cr:paint_with_alpha(widget.opacity)
 
     -- Register the widget for input handling
     wibox:widget_at(widget, base.rect_to_device_geometry(cr, 0, 0, width, height))
diff --git a/lib/wibox/widget/base.lua b/lib/wibox/widget/base.lua
index f57c01f5..dd37d5c0 100644
--- a/lib/wibox/widget/base.lua
+++ b/lib/wibox/widget/base.lua
@@ -116,6 +116,15 @@ function base.make_widget(proxy, widget_name)
         end
     end
 
+    -- Add opacity property and setter.
+    ret.opacity = 1
+    function ret:set_opacity(b)
+        if b ~= self.opacity then
+            self.opacity = b
+            self:emit_signal("widget::updated")
+        end
+    end
+
     -- Add __tostring method to metatable.
     ret.widget_name = widget_name or object.modulename(3)
     local mt = {}