TextArea still has a cursor, until it's had focus and then lost it

[davep]

Sort of related to #3722: a TextArea still has a cursor when not focused, if it hasn't received focus yet. For example, this code:

from textual.app import App, ComposeResult
from textual.widgets import Input, TextArea

class TextAreaCursorApp(App[None]):

    def compose(self) -> ComposeResult:
        yield Input()
        yield TextArea()

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

starts up looking like this:

[darrenburns]

Cheers - I reckon this will be changing a True to a False somewhere 😄

[TomJGooding]

I had a quick look at this and found that if you set cursor_blink = False (needed for snapshot testing), the TextArea still has a cursor even after focussing then blurring:

from textual.app import App, ComposeResult
from textual.widgets import Input, TextArea


class TextAreaCursorApp(App[None]):
    def compose(self) -> ComposeResult:
        input = Input()
        text_area = TextArea()
        input.cursor_blink = False
        text_area.cursor_blink = False
        yield input
        yield text_area


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

Then I spotted that the _on_blur method actually also seems to set the cursor to be visible which is confusing? Changing this to False has no effect, which suggests the cursor visibility must actually be updated elsewhere...?

textual/src/textual/widgets/_text_area.py

Lines 1291 to 1292 in 6459878

	def _on_blur(self, _: events.Blur) -> None:
	self._pause_blink(visible=True)

EDIT: Ah-ha, I missed that it also has this watch method!

textual/src/textual/widgets/_text_area.py

Lines 523 to 525 in 6459878

	def watch_has_focus(self, value: bool) -> None:
	self._cursor_visible = value
	super().watch_has_focus(value)

[darrenburns]

Oh yeah, the _on_blur can probably be removed. It was intended to ensure that the cursor remains visible when it's blurred for consistency. Otherwise the visibility of the cursor depended on when you blurred the widget.

I was thinking initialising self._cursor_visible to False in the constructor might be enough.

[TomJGooding]

Just to note for whoever picks this up (maybe me!), potentially any fix should also account for this issue:

• Widgets with a flashing cursor should turn them off when not on current screen #3405

[TomJGooding]

Oh yeah, the _on_blur can probably be removed. It was intended to ensure that the cursor remains visible when it's blurred for consistency. Otherwise the visibility of the cursor depended on when you blurred the widget.

Sorry I'm not sure I fully understand this - is that just the old implementation, or related to #2476?

[darrenburns]

Sorry, I meant the _on_blur could be removed because we could handle the logic of pausing the blink insidewatch_has_focus instead, rather than doing blur-related stuff in 2 places. We'll probably need to pause blink in watch_has_focus with visible=False.

[darrenburns]

I'm going to pick this up now.

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