Focus navigation doesn't take transform into account when computing bounds #55338
Labels
a: desktop
Running on desktop
f: focus
Focus traversal, gaining or losing focus
framework
flutter/packages/flutter repository. See also f: labels.
has reproducible steps
The issue has been confirmed reproducible and is ready to work on
Comments
iapicca
added
in triage
|
I ran OutputThe code compiles fine for me. I don't know why DefaultFocusTraversal is missing(?) for you (what is the error?). It's a standard Flutter widget. For me it's imported via this path: But I realized it has no effect anyway, so please try this. import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key key}) : super(key: key);
Widget button(String t) => Padding(
padding: EdgeInsets.symmetric(horizontal: 2.0),
child: RaisedButton(color: Colors.green, child: Text(t), onPressed: () {}),
);
Widget triangle() => Column(children: [
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [button('a'), button('b'), button('c')]),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [button('d'), button('e'), button('f')]),
]);
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: Column(mainAxisAlignment: MainAxisAlignment.center, children: [
triangle(),
Transform.scale(scale: 0.5, alignment: Alignment.topCenter, child: triangle()),
]),
),
);
}
} |
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TahaTesser
changed the title
|
Hi @lynn Using Tab to switch
Using Up and down arrow keys to switch (here we can see focus direction scaled down widgets)
Can you please confirm the issue is same as this? |
TahaTesser
added
the
waiting for customer response
|
@TahaTesser yes, I think I can see the issue in your second GIF. To see it most clearly, try moving with the arrow keys like this around the small widgets: Sometimes, it will jump from EDIT: Actually, it looks like there is an issue with Tab too? In your GIF, the order is different in the small widgets ( |
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bot
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the
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Yes, I think this is because the focus traversal code isn't taking the context's transform into account when building the geometry to decide which widget to visit next. |
gspencergoog
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gspencergoog
added
a: desktop
TahaTesser
added
framework
1 task
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Steps to Reproduce
flutter create bug.lib/main.dartwith:Expected results
The focus moves the same way in both rectangles of buttons.
Actual results
Sometimes, focus moves diagonally in the scaled-down example, e.g from
e⬈cwhen I press the “right” D-pad button on my gamepad withefocused. It should go to frome⮕f.Investigation
Adding logging to
DirectionalFocusTraversalPolicyMixin.inDirectionshows that this is because the scaled-down buttonFocusNodes have arectwith width/height equal to the originals, i.e. measured in local coordinates rather than global coordinates.So,
cis detected as being “in-band” ofewhen moving right, becausec's rect extends too far down. Ifchappens to be first in the in-band list, it will get selected rather thanf.Suggested Fix
In
flutter/lib/src/widgets/focus_manager.dart, transform the whole rectangle, rather than only transforming itstopLeftpoint and leavingsizeuntouched:/// Returns the global rectangle of the attached widget's [RenderObject], in /// logical units. Rect get rect { assert( context != null, "Tried to get the bounds of a focus node that didn't have its context set yet.\n" 'The context needs to be set before trying to evaluate traversal policies. This ' 'is typically done with the attach method.'); final RenderObject object = context.findRenderObject(); - final Offset globalOffset = MatrixUtils.transformPoint(object.getTransformTo(null), object.semanticBounds.topLeft); - return globalOffset & object.semanticBounds.size; + return MatrixUtils.transformRect(object.getTransformTo(null), object.semanticBounds); }flutter doctor
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