How bad would it be to drive the anode of an LED from a GPIO pin?

[oneoverf]

I’m working with an illuminated encoder that has its LEDs’ cathodes tied together. Can I safely drive their anodes with GPIO pins (with a resistor on each)?

 

[PaulStoffregen]

Yes. Just connect the cathode to ground. Of course, use reasonable resistors, like 150 ohms or higher.