These are new capabilities, recently added to ncurses. Applications
are supposed to use these, instead of XM (to enable focus events). So,
remove "CSI ? 1004h" from XM.
wmemset() is heavily optimized, and in some cases, *much* faster than
manually initializing the new image pixels.
Furthermore, assume calloc() is better at initializing memory to zero,
and use that when initializing new pixels in a transparent image.
When trimming trailing empty rows from the final image, handle the RA
region correctly:
* If image is transparent, trim down to the last non-empty pixel row,
regardless of whether it is inside or outside the RA region.
* If image is opaque, trim down to either the last non-empty pixel
row, or the RA region, whatever is the largest height.
The raster attributes is, really, just a way to erase an area. And, if
the sixel is transparent, it's a nop.
The final text cursor position depends, not on our image size (which
is based on RA), but on the final graphical cursor position.
However, we do want to continue using it as a hint of the final image
size, to be able to pre-allocate the backing buffer.
So, here's what we do:
* When trimming trailing transparent rows, only trim the *image*, if
the graphical cursor is positioned on the last sixel row, *and* the
sixel is transparent.
* Opaque sixels aren't trimmed at all, since RA in this acts as an
erase that fills the RA region with the background color.
* The graphical cursor position is always adjusted (i.e. trimmed),
since it affects the text cursor position.
* The text cursor position is now calculated from the graphical cursor
position, instead of the image height.
After emitting a sixel, place the cursor on the character row touched
by the last sixel. The last sixel _may_ not be a multiple of 6
pixels, *if* the sixel had an explicit width/height set via raster
attributes.
This is an intended deviation from the DEC cursor placement algorithm,
where the cursor is placed on the character row touched by the last
sixel's *upper* pixel.
The adjusted algorithm implemented here makes it much easier for
applications to handle text-after-sixels, since they can now simply
assume a single text newline is required to move the cursor to a
character row not touched by the sixel.
Virtual machine monitor programs (e.g. QEMU, Cloud Hypervisor) expose
guest consoles as PTYs. With this patch, foot can access these guest
consoles.
Usually, the program used for accessing these PTYs is screen, but
screen is barely developed, doesn't support resizing, and has a bunch
of other unrelated stuff going on. It would be nice to have a
terminal emulator that properly supported opening an existing PTY.
The VMM controls the master end of the PTY, so to the other end (in
this case foot), it just behaves like any application running in a
directly-opened PTY, and all that's needed is to change foot's code to
support opening an existing PTY rather than creating one.
Co-authored-by: tanto <tanto@ccc.ac>
Before this patch, we reported scaled pixel values. This was rather
useless, since applications have no way of getting the scaling factor,
to "scale up" e.g. images.
Furthermore, the most common use of these queries are probably to
calculate the dimensions to use when emitting sixels.
Closes#1643
This functions reads the four top/left/bottom/right parameters,
validates them, and converts relative row numbers to absolute.
Returns true if the params are valid, otherwise false.
* DECCARA - change attributes in rectangular area
* DECRARA - reverse attributes in rectangular area
* DECCRA - copy rectangular area
* DECFRA - fill rectangular area
* DECERA - erase rectangular area
Not implemented:
* DECSERA - selective erase rectangular area
