Most Mouse Deltas Rounded to Zero In Textual 2.0

[ddkasa]

The Bug

Most mouse movement deltas are unusable due to being rounded to zero after the smooth scrolling update. Unless rapid mouse movements are applied, the deltas are almost certainly zero.

1.0.0

Textual-1.0.0.webm

2.0.4

Textual-2.0.4.webm

Expected behaviour would be the original, unless this was intended side effect when converting to integers to the new properties, as most of the float values are below/above ±0.5 depending on if its a negative value or not, so they get rounded to zero.

One idea would be to give the user access to the float values, but that seems a bit half baked, as the new properties would become mostly useless.

Another idea would be clamping the values to ±1 or the closest none-zero value.

MRE

from textual.app import App, ComposeResult
from textual.events import MouseMove
from textual.widgets import Placeholder


class BugReportApp(App):
    def on_mouse_move(self, event: MouseMove) -> None:
        print(f"{event.delta_x=} {event.delta_y=}")


if __name__ == "__main__":
    BugReportApp().run()

Textual Diagnostics

Versions

Name	Value
Textual	2.0.4
Rich	13.9.4

Python

Name	Value
Version	3.12.5
Implementation	CPython
Compiler	GCC 14.2.1 20240801 (Red Hat 14.2.1-1)
Executable	/home/dk/dev/tmp/textual-sandbox/.venv/bin/python3

Operating System

Name	Value
System	Linux
Release	6.12.13-100.fc40.x86_64
Version	#1 SMP PREEMPT_DYNAMIC Sat Feb 8 17:10:01 UTC 2025

Terminal

Name	Value
Terminal Application	Kitty
TERM	xterm-kitty
COLORTERM	truecolor
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=274, height=54
legacy_windows	False
min_width	1
max_width	274
is_terminal	True
encoding	utf-8
max_height	54
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

[github-actions]

We found the following entry in the FAQ which you may find helpful:

• How can I select and copy text in a Textual app?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

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[github-actions]

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