A 12pt Font Should Be the Same Size Everywhere (2012)
I have mixed feelings about this.  I get the point about touch: i.e. the button should have a fixed size in proportion to your finger.  However in other scenarios I am not sure size should be constant.  In most cases, you have to factor in the distance to the viewer.  This is, probably "projection angle in the retina" is a more useful invariant.<p>For example, in a big TV that is far from you, you want things to be bigger than in a monitor, that is closer.  And in a laptop, you probably want it even smaller.<p>"Design by pixel" takes this into account somewhat indirectly because most display are designed to have their pixel density in inverse proportion to the size of the display, which is also inversely correlated to the expected usage distance.  Sometimes technology changes our expectations of definitions and things become small, until designs catch up with the new expected pixel density.  We have worked around this problem with pixel density factors on retina/QHD.<p>I agree that all this in the is a evolutionary "hack".  But I am not sure that the proposed solution, even though more rational sounding, actually makes things better.