Block touch input while the magnifier is running by Boumtchack · Pull Request #20357 · nvaccess/nvda

Boumtchack · 2026-06-17T13:34:39Z

Link to issue number:

Closes #20038

Summary of the issue:

Touch screen input causes incorrect mappings when the NVDA magnifier is running. Touch input must be disabled while the magnifier is active to prevent this conflict.

Description of user facing changes:

On installed copies of NVDA, touch gestures are silently blocked while the magnifier is running. An earcon plays on each blocked gesture so the user knows the touch was received but suppressed. On portable copies, copies running from source, or without UI access, a warning dialog appears when the magnifier starts to inform the user that touch input cannot be intercepted and may not behave as expected.

Description of developer facing changes:

A blockTouchInput: bool flag is added to touchHandler. In TouchHandler.pump(), when the flag is True, gestures are skipped and an earcon is played instead of executing the gesture. Magnifier._startMagnifier sets touchHandler.blockTouchInput = True if the handler is active, or schedules a gui.messageBox warning via wx.CallAfter otherwise. Magnifier._stopMagnifier unconditionally resets the flag to False.

Description of development approach:

Keeps the touch handler running and blocks only at the gesture execution layer in pump(), which runs on the main thread and avoids any threading concerns with audio feedback.

Testing strategy:

unit

Known issues with pull request:

Code Review Checklist:

Documentation:
- Change log entry
- User Documentation
- Developer / Technical Documentation
- Context sensitive help for GUI changes
Testing:
- Unit tests
- System (end to end) tests
- Manual testing
UX of all users considered:
- Speech
- Braille
- Low Vision
- Different web browsers
- Localization in other languages / culture than English
API is compatible with existing add-ons.
Security precautions taken.

SaschaCowley · 2026-06-17T23:33:07Z

@Boumtchack this approach will not work. Disabling NVDA's touch support does *NOT disable touchscreen input, it simply disables NVDA's processing of touch events. Arguably this makes the situation worse, as touching the screen in this state will silently perform actions. While we have no way of preventing this in portable copies (we can't intercept touch inputs in portables), we already intercept all touch events when touch support is enabled in installed copies.

What we need to do is continue to block touch inputs but alert the user that touch support is unavailable. Of course, if NVDA's touch support is disabled, or NVDA is running from source, portable, or (I think) without UI access, we still need to pop up a dialog alerting the user that the touch screen will not behave as expected while the magnifier is running.

seanbudd · 2026-06-23T02:18:21Z

@SaschaCowley - can you check the approach now?

SaschaCowley

I think the logic is flawed, but this is the right direction.

hwf1324 · 2026-07-01T01:24:34Z

Please change the title of this PR to avoid confusion.

Boumtchack · 2026-07-01T07:48:37Z

how would you change the title? it seems ok to me

hwf1324 · 2026-07-01T07:51:16Z

For example: “Block touch input while the magnifier is running”?

Copilot

Pull request overview

This PR aims to prevent mis-mapped touchscreen behavior while NVDA’s magnifier is active by blocking NVDA touch gesture execution when touch interception is available, and warning the user when interception isn’t possible (portable/source/no UI access scenarios).

Changes:

Add a touchHandler.blockTouchInput flag and skip gesture execution in TouchHandler.pump() while the flag is set.
Update magnifier start/stop logic to enable/disable touch blocking, or show a warning dialog when touch input can’t be intercepted.
Add/adjust unit tests covering magnifier + touchscreen interactions.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

File	Description
tests/unit/test_magnifier/test_magnifierTouchscreen.py	New unit tests for touch blocking / warning behavior when magnifier starts/stops.
tests/unit/test_magnifier/test_magnifier.py	Test setup/teardown adjustments and focus coordinate mocking to support magnifier behavior in tests.
source/touchHandler.py	Add global `blockTouchInput` and block gesture execution (with feedback) during pump.
source/_magnifier/magnifier.py	Toggle touch blocking on magnifier start/stop; warn when touch interception isn’t available.

seanbudd · 2026-07-08T02:04:58Z

+				reason = pgettext(
+					"magnifier",
+					# Translators: Warning when the magnifier starts on a portable/source copy with a touchscreen.
+					"Touch screen input cannot be used because NVDA is not installed. ",
+				)


Suggested change

reason = pgettext(

"magnifier",

# Translators: Warning when the magnifier starts on a portable/source copy with a touchscreen.

"Touch screen input cannot be used because NVDA is not installed. ",

)

reason = pgettext(

"magnifier",

# Translators: Warning when the magnifier starts on a portable/source copy with a touchscreen.

"Touch screen input is not supported in this version of NVDA. ",

)

 		self._stopTimer()
 		self._isActive = False
+		if touchHandler.handler is not None:
+			touchHandler.blockTouchInput = False


seanbudd · 2026-07-08T02:11:33Z

 		for preheldTracker, tracker in self.trackerManager.emitTrackers():
+			if blockTouchInput:
+				winsound.MessageBeep(winsound.MB_ICONASTERISK)
+				continue


Yes I think this might be too noisy.

Suggested change

for preheldTracker, tracker in self.trackerManager.emitTrackers():

if blockTouchInput:

winsound.MessageBeep(winsound.MB_ICONASTERISK)

continue

if blockTouchInput:

winsound.MessageBeep(winsound.MB_ICONASTERISK)

return

for preheldTracker, tracker in self.trackerManager.emitTrackers():

+	def testStopMagnifierUnblocksTouchInput(self):
+		"""blockTouchInput is reset to False when the magnifier stops with the touch handler active."""
+		self.magnifier._stopTimer = MagicMock()
+		self.magnifier._isActive = True
+		touchHandler.blockTouchInput = True
+		self.addCleanup(setattr, touchHandler, "blockTouchInput", False)
+
+		with patch("touchHandler.handler", new=MagicMock()):
+			self.magnifier._stopMagnifier()
+
+		self.assertFalse(touchHandler.blockTouchInput)


seanbudd

Thanks @Boumtchack

seanbudd · 2026-07-08T02:13:21Z

+					"magnifier",
+					# Translators: Warning when magnifier is started on a device with a touch screen but NVDA's touch support is disabled.
+					"Touch screen input cannot be used because NVDA touch support is disabled. ",
+				)


wouldn't this message also appear if touch support is enabled?

also maybe I missed it but do we have a warning message for when we block touch input

stale

Boumtchack added 2 commits June 17, 2026 15:23

touchscreen first draft

1b40ff7

unit tests

fa66cab

Boumtchack marked this pull request as ready for review June 17, 2026 15:08

Boumtchack requested a review from a team as a code owner June 17, 2026 15:08

Boumtchack requested a review from seanbudd June 17, 2026 15:08

Merge branch 'beta' into feature/disableTouchscreen

67e098a

SaschaCowley marked this pull request as draft June 17, 2026 23:33

Boumtchack added 2 commits June 22, 2026 14:36

changed approach

ce3a3b0

Merge branch 'beta' into feature/disableTouchscreen

3215ead

Boumtchack marked this pull request as ready for review June 22, 2026 13:32

seanbudd added the conceptApproved Similar 'triaged' for issues, PR accepted in theory, implementation needs review. label Jun 23, 2026

seanbudd requested a review from SaschaCowley June 23, 2026 02:17

SaschaCowley requested changes Jun 23, 2026

View reviewed changes

Comment thread source/_magnifier/magnifier.py Outdated

Comment thread source/_magnifier/magnifier.py Outdated

Comment thread source/touchHandler.py Outdated

Comment thread tests/unit/test_magnifier/test_magnifier.py

SaschaCowley marked this pull request as draft June 23, 2026 06:14

review modifications

9befad6

Boumtchack marked this pull request as ready for review June 24, 2026 06:28

seanbudd requested a review from SaschaCowley June 25, 2026 04:12

seanbudd reviewed Jun 25, 2026

View reviewed changes

Comment thread tests/unit/test_magnifier/test_magnifier.py Outdated

Comment thread source/_magnifier/magnifier.py Outdated

Comment thread source/_magnifier/magnifier.py Outdated

SaschaCowley approved these changes Jun 25, 2026

View reviewed changes

seanbudd added this to the 2026.2 milestone Jun 25, 2026

seanbudd marked this pull request as draft June 29, 2026 05:06

Boumtchack added 2 commits June 29, 2026 10:56

review

fb3ecd3

review ruff

c2093e4

Boumtchack marked this pull request as ready for review June 29, 2026 14:03

seanbudd reviewed Jun 30, 2026

View reviewed changes

Comment thread tests/unit/test_magnifier/test_magnifierTouchscreen.py Outdated

refactoring

2ca6058

seanbudd reviewed Jun 30, 2026

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Comment thread tests/unit/test_magnifier/test_magnifierTouchscreen.py Outdated

Boumtchack changed the title ~~touchscreen and magnifier support~~ Block touch input while the magnifier is running Jul 1, 2026

tests refacto

a958efa

Copilot AI review requested due to automatic review settings July 7, 2026 15:25

Copilot started reviewing on behalf of Boumtchack July 7, 2026 15:26 View session

Copilot AI reviewed Jul 7, 2026

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seanbudd previously approved these changes Jul 8, 2026

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seanbudd reviewed Jul 8, 2026

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seanbudd self-requested a review July 8, 2026 02:13

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Boumtchack commented Jun 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Link to issue number:

Summary of the issue:

Description of user facing changes:

Description of developer facing changes:

Description of development approach:

Testing strategy:

Known issues with pull request:

Code Review Checklist:

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SaschaCowley commented Jun 17, 2026

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Boumtchack commented Jun 17, 2026 •

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