Godot Get Window Size & Screen Size: Quick Solution

# Get current window/viewport size
var window_size = get_viewport().get_visible_rect().size
print("Window size: ", window_size)

# Get full screen dimensions
var screen_size = DisplayServer.screen_get_size()
print("Screen size: ", screen_size)

# Godot 4.x - Viewport size
var viewport_size = get_viewport_rect().size
 
# Window size (different approach)
var window = get_window()
var size = window.size