Now that we explicitly set P2=1, we can safely emit a "Set Raster
Attributes" command, to tell the terminal the final size of the image
up front.
Also fix the ‘pad’ parameter (horizontal aspect ratio); XTerm rejects
sixels with pan or pad set to 0.
This indicates that empty pixels should "remain at their current
color". I.e. it makes them transparent.
This is in contrast to P2=0|2, where empty pixels are filled with the
"current background color" (which is either sixel color register #0,
or the current ANSI background color, depending on terminal and its
sixel implementation).
Note that due to what is most likely a bug, XTerm will behave as if
P2=1 if P2 is either left unset, or explicitly set to 0 or 2, as long
as we do *not* emit a "Set Raster Attributes" command.
- separate the methods into its own module.
- add constants NCVISUAL_OPTION_ADDALPHA, NCVISUAL_OPTION_HORALIGNED, NCVISUAL_OPTION_VERALIGNED
- add NcRgba type.
- update the docs.
the media code that makes up non-core libnotcurses called
into lookup_rgba(). instead, have them use the new
funtion ncvisual_blitter_geom() to access the actual blitter
being used. we can then hide lookup_blitset(), which ought
never have been exported. closes#1519.
Require a known-good TERM heuristic match to enable
quadrants (NCBLIT_2x2); they otherwise decay to halves
(NCBLIT_2x1). The only terminal that supports quadrants
but does not support sextants is the Linux console, where
we program quadrants directly into the font table,
like a beast. Closes#1517, and #1298 if we're lucky.
deprecate ncvisual_geom() in favor of new ncvisual_blitter_geom(), which allows caller to get the blitter used. replace the checks and calculations in ncvisual_render() with a call to ncvisual_blitter_geom(), unifying the two paths (and eliminating several bugs in the unloved ncvisual_geom()).
nick black
Daniel Eklöf
joseLuís