third display_power option to use wlr-randr i.e. for RPi5 wayland desktop

Author: paddywwoof

src/picframe/config/configuration_example.yaml

@@ -22,7 +22,7 @@ viewer:
   display_y: 0                            # offset from top of screen (can be negative)
   display_w: null                         # width of display surface (null->None will use max returned by hardware)
   display_h: null                         # height of display surface
-  display_power: 0                        # default=0. choices={0, 1}, 0 will use legacy `vcgencmd` and 1 will use `xset` to blank the display
+  display_power: 0                        # default=0. choices={0, 1, 2}, 0 will use legacy `vcgencmd`, 1 will use `xset`, 2 will use 'wlr-randr' to blank the display
   use_glx: False                          # default=False. Set to True on linux with xserver running. NB use_sdl2 might need to be False for this to work.
   use_sdl2: False                         # default=True. pysdl2 can use display without xserver, it should be installed as a dependency of pi3d
                                           # but might need `sudo apt install libsdl2-dev` if picframe gives errors about missing sdl2

src/picframe/viewer_display.py

@@ -154,6 +154,14 @@ def display_is_on(self, on_off):
             except Exception as e:
                 self.__logger.debug("Display ON/OFF is xset via dpms, but an error occured")
                 self.__logger.debug("Cause: %s", e)
+        elif self.__display_power == 2:
+            try:  # try wlr-randr for RPi5 with wayland desktop
+                wlr_randr_cmd = ["wlr-randr", "--output", "HDMI-A-1"]
+                wlr_randr_cmd.append('--on' if on_off else '--off')
+                subprocess.call(wlr_randr_cmd)
+            except Exception as e:
+                self.__logger.debug("Display ON/OFF is wlr-randr, but an error occured")
+                self.__logger.debug("Cause: %s", e)
         else:
             self.__logger.warning("Unsupported setting for display_power=%d.", self.__display_power)