Previously, alignment did exist, but it only changed whole text block
position in relation to a fixed point. This was later renamed to "Anchor".
Now it correctly aligns each line of text. Alignment works with newline
character and word wrapping.
Currently newline characters can't be entered directly, but this should
be resolved soon.
To keep existing anchoring feature, new DNA fields are added and
values from old alignment are copied there.
This PR is part of bigger change [1], and originally I expected to
implement this feature at later stage. But the design called for drawing
text character by character, which would mean, that I would have to
rewrite text alignment anyway.
To render the text, a struct is built, where position and width of each
character is stored. In addition, width of each line is stored. This allows
to implement proper text alignment feature, instead of existing
anchoring. Text is then drawn character by character in a loop.
There are some small differences in text rendering, since this is only
approximation of how BLF library draws glyphs, but it is very close.
For text bounbox, `BLF_boundbox()` is used on per line basis,
because some fonts do not use their full height and this information
is not available on VSE side.
[1] https://projects.blender.org/blender/blender/issues/126547
Pull Request: https://projects.blender.org/blender/blender/pulls/126660
77a5478c0f