title: How does a Unicode character get mapped to a glyph in a font?
body: <p>I am wondering, that each char in Unicode has a code point; what's the analogous term for a character in a font?</p>
  
  <p>I never understood the part of the process when a decoded file needs to be mapped to font (or fonts, by some modern font substitution technology).</p>
  
  <p>For example, when a text editor has decoded a file from its character encoding, and suppose there's Greek alpha α (U+03B1). What's the exact process this app chooses a particular glyph in a font? Most app has a preferred font. Let's say it's Courier. (And what happens in the case of a rare Unicode char likethe heart ♥ (U+2665), that's not in the default font? How does the app know the font doesn't contain that char?)</p>
  
  <p>Does a font contain meta info about what symbols it has?</p>
  
  <p>If 2 fonts both have the symbol alpha, do they necessarily share the same “code point”? Or is it dependent on the type of font such as Type1, Type3, TrueType, OpenType? ...</p>
  
  <p>Thanks for any pointers or references.</p>