Kanshi Scale Issue -- Numerical Precision vs swaymsg / IPC about kanshi

[emersion]

This is a Sway bug.

[jameswalmsley]

Hi @emersion I've been looking at the cause of this.
The scale is converted to a fixed type on the wayland protocol.

This is 24-bits of integer, and only 8-bits of decimal precision.

I guess that's where the precision is lost.

The protocol would have to send the scale as e.g. a string or pack the float into
and int32 to keep the precision.

I'll make a PR to test this and see what the you all over at sway think.

Can imagine you don't want to break the wayland type system.

[emersion]

Even if there are rounding errors with the scale (which isn't a big deal IMHO), the rects should have the same size.

[jameswalmsley]

Thanks for the quick responses.

I've created an issue demonstrating the rounding error with the wlr-output-management
protocol.

swaywm/sway#4896