This is the beginning of supporting 2d rendering in 3d space. The idea
is that a canvas can be in 2d orthographic space (not attached to any
entity with a 3d transform), or in 3d perspective space (attached to an
entity with a 3d transform, either as a child of the camera, or of some
object in 3d space).
It will replace the current HUD code when it's working.
And add a function to process a passage into a set of views with glyphs.
The views can be flowed: they have flow gravity and their sizes set to
contain all the glyphs within each view (nominally, words). Nothing is
tested yet, and font rendering is currently broken completely.
Font and text handling is very much part of user interface and at least
partially independent of rendering, but does fit it better with GUI than
genera UI (ie, both graphics and text mode), thus libQFgui as well as
libQFui are built in the ui directory.
The existing font related builtins have been moved into the ruamoko
client library.
A passage object has a list of all the text objects in the given string,
where the objects represent either white space or "words", as well as a
view_t object representing the entire passage, with paragraphs split
into child views of the passage view, and each paragraph has a child
view for every text/space object in the paragraph.
Paragraphs are split by '\n' (not included in any object).
White space is grouped into clumps such that multiple adjacent spaces
form a single object. The standard ASCII space (0x20) and all of the
Unicode characters marked "WS;<compat> 0020" are counted as white space.
Unless a white space object is the first in the paragraph, its view is
marked for suppression by the view flow code.
Contiguous non-white space characters are grouped into single objects,
and their views are not suppressed.
All text object views (both white space and "word") have their data
pointer set to the psg_text_t object representing the text for that
view. This should be suitable for simple text-mode unattributed display.
More advanced rendering would probably want to create suitable objects
and set the view data pointers to those objects.
No assumption is made about text direction.
Passage and paragraph views need to have their primary axis sizes set
appropriately, as well as their resize flags. Their xlen and ylen are
both set to 10, and xpos,ypos is 0,0. Paragraph views need their
setgeometry pointer set to the appropriate view_flow_* function.
However, they are set up to have their secondary axis set automatically
when flowed.
Text object views are set up for automatic flowing: grav_flow, 0,0 for
xpos,ypos. However, xlen and ylen are also both 0, so need to be set by
the renderer before attempting to flow the text.
