Text alignment should be with respect to descent and ascent lines rather than text bounding box

[fryguybob]

(Imported from http://code.google.com/p/diagrams/issues/detail?id=33. Original issue from byor...@gmail.com on June 8, 2011, 05:14:26 PM UTC)

Currently text is aligned with respect to its actual bounding box; instead, it ought to be aligned with respect to a box with left and right edges given by the bounding box and top and bottom edges given by the ascent and descent line of the font. (See
http://cairographics.org/tutorial/#L1understandingtext). The current approach means that different text elements placed next to each other are not vertically aligned. For example, this looks really bad:

{{{
letterBlock c = square # scale 1.5 <> text [c]

example = hcat $ map letterBlock ['a'..'z']
}}}

Also, the code for accomplishing this ought to be factored out of the cairo backend into diagrams-lib so other backends can make use of it.

[fryguybob]

(Imported. Original comment by byor...@gmail.com on January 19, 2012, 10:04:50 PM UTC)

mgsloan fixed this incidentally to making some other improvements to the text API. Yay!

[fryguybob]

(Imported. Original comment by felipe.l...@gmail.com on January 19, 2012, 10:15:40 PM UTC)

Where is this fix? I've looked at diagrams-core and diagrams-lib but didn't find anything.

[fryguybob]

(Imported. Original comment by byor...@gmail.com on January 20, 2012, 02:19:56 PM UTC)

This was a bug specific to the cairo backend, so it's in diagrams-cairo: http://patch-tag.com/r/byorgey/diagrams-cairo/snapshot/hash/20111224013227-57657-9b40845a3aaa990c46a1a4839201e7e29a0af121/patch