mouse: encode pixel reports against the cell size we advertise

A pane is told how big a cell is twice -- in mode 2048's resize report and
in the XTWINOPS answers -- and the mouse encoder was told something else: a
1x1 cell, so that cell coordinates and "pixels" were the same number.

That held until a program turned on SGR-pixel mouse (mode 1016) by itself.
Textual does, the moment in-band resize works, and then divides every
coordinate it is sent by the pixels-per-cell we advertised: a click 30 cells
across and 9 down arrived as (3, 0), so every click in a Textual app landed
in the top-left corner.

Hand the encoder the cell size the pane already has, and put the pointer in
the middle of its cell. A size that contradicts what the same pane was told
about itself is the lie, not the precision.

0 files changed, 0 insertions, 0 deletions