console.lua: hide the cursor when unfocused

This is commonly done to understand whether a window is focused. This
explicitly checks if focused is false instead of unavailable to not
break the cursor where focused is unimplemented like on --vo=drm.

The cursor is taller than the input text so it is made transparent
instead of completely removing it so that the log doesn't move up and
down while toggling focus. Alternatively, cheight = opts.font_size * 8
can be changed to 7.

player/lua/console.lua

@@ -384,7 +384,8 @@ function update()
     -- horizontal borders.
     local cheight = opts.font_size * 8
     local cglyph = '{\\r' ..
-                   '\\1a&H44&\\3a&H44&\\4a&H99&' ..
+                   (mp.get_property_native('focused') == false
+                    and '\\alpha&HFF&' or '\\1a&H44&\\3a&H44&\\4a&H99&') ..
                    '\\1c&Heeeeee&\\3c&Heeeeee&\\4c&H000000&' ..
                    '\\xbord0.5\\ybord0\\xshad0\\yshad1\\p4\\pbo24}' ..
                    'm 0 0 l 1 0 l 1 ' .. cheight .. ' l 0 ' .. cheight ..
@@ -1317,6 +1318,7 @@ end)
 mp.observe_property('osd-width', 'native', update)
 mp.observe_property('osd-height', 'native', update)
 mp.observe_property('display-hidpi-scale', 'native', update)
+mp.observe_property('focused', nil, update)
 
 -- Enable log messages. In silent mode, mpv will queue log messages in a buffer
 -- until enable_messages is called again without the silent: prefix.