TextKit large numbers

largeNumbers.swift

// This file defines two numbers to use to mean "really big".
// The first is called LargeNumberForText, and it was not arbitrarily chosen.
// The actual value was chosen to be around the largest floating point value possible that can preserve at least pixel precision.
// Because of the nature of floating point numbers, the bigger they get, the less precise they get.
// It is not wise to use bigger dimensions for text system objects because, even if you ever fill all that space,
// by the time you get to the far reaches, the letters won't have the precision necessary to look and act correctly.
// This limitation of floating point coordinates goes all the way down into postscript, and holds for any type postscript graphics.
// Because the Cocoa text system respects this limit in various ways, a second constant, NotQuiteAsLargeNumberForText,
// is used for the field-like text views created by the FieldAspect class. This is simply half of LargeNumberForText;
// at sizes as large as LargeNumberForText, the text system stops aligning text, for various reasons.

// Apple mention that recommended text Container size limit should not be more that 1.0e7,
// otherwise text will become blurry.
let largeNumberForText = 1.0e7

// Too large and the Cocoa text system stops aligning text, for various reasons
let notQuiteAsLargeNumberForText = 0.5e7