Unify the API for working with fonts when Pango is enabled.

[joefreeman]

Relating to the discussion of issue #525, I've tried to make sure that the API works the same whether or not Pango is enabled. Previously, calling addFont with Pango enabled would cause the font rendering to break. Also, the font had to be referenced by family name. With this change, the addFont call is optional, but if it is called, the font can be referenced using the name provided to the Font constructor.

So, after setting up the font like this:

var font = new Font('myFontAlias', '/path/to/MyFont.ttf');
context.addFont(font);

This:

context.font = '50px myFontAlias';

Is equivalent to this (assuming the font's family name is 'My Font'):

context.font = '50px \'My Font\'';

But I'm not familiar with C++, Pango or Cairo, so my changes might be no good.

[LinusU]

Hi @joefreeman, I'm sorry that this has fallen thru the cracks. Would you mind rebasing on master? I will make sure to review this. Thanks 👍

[joefreeman]

No need - looks like this is working in master now. I'll close this and my issue...

[LinusU]

@joefreeman Are you sure? Did you test it with built pango support?