An electronic device of an embodiment of the invention is for at least partially displaying a pixel of a displayable image. The electronic device includes a first reflector and a second reflector that define an optical cavity therebetween, and which is selective of a visible wavelength at an intensity by optical interference. The electronic device also includes a mechanism to allow optical properties of the optical cavity to be varied. The visible wavelength and/or the intensity are thus variably selectable in correspondence with the pixel of the displayable image.