问题
When programming for the iPad, font (and other) sizes are specified in "points." I have seen reference to a point as a pixel that is independent of screen resolution. But I am having trouble finding definite confirmation of how big a point is in real terms (that is, in terms of inches). Is a point equal to one pixel on the standard iPad screen, so 1pt = 1/132in? And then, to confirm, this means that an "iOS point" is a different unit than the printer's point = 1/72in?
Thanks.
回答1:
See here and here (scroll down to points vs. pixels) for the official word. Basically, a point is one pixel on a non-retina device (so the size varies between the iPad and the iPhone - it isn't related to a printer's point) and 2 pixels on a retina device (which has twice the number of pixels in each direction).
Drawing and positioning is done in points to allow the same code to run on both types of device - the frameworks will fill in the gaps to make drawing smoother on retina devices.
An iPad point is different to an iPhone point, which is different to a printers point, to answer your question.
来源：https://stackoverflow.com/questions/8687124/printers-points-vs-ios-points