Add markInsets property to Checkbox by Munawer-Ali · Pull Request #188258 · flutter/flutter

Munawer-Ali · 2026-06-19T13:36:11Z

This PR adds an optional padding property to the Checkbox widget.
Currently the check mark always fills the entire checkbox box, with no way to add space between the mark and the box edges (see #188031). This adds a padding field (EdgeInsetsGeometry?) that insets the check mark — and the indeterminate dash — inside the box.

Fixes flutter/flutter#188031

Tests

Added to test/material/checkbox_test.dart:

Checkbox.padding defaults to null
Checkbox with no padding paints at full stroke width (backward-compat)
Checkbox.padding shrinks the check mark and its stroke
Checkbox.padding shrinks the indeterminate dash
Checkbox.padding larger than the box collapses the mark without crashing
Checkbox asserts when padding is negative

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google-cla · 2026-06-19T13:36:16Z

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Code Review

This pull request adds a padding property to the Checkbox widget, which insets and proportionally scales the check mark and indeterminate dash. The review feedback suggests documenting that this padding is ignored on iOS and macOS when using Checkbox.adaptive, adding padding to CheckboxThemeData for global styling, correcting the documentation regarding its default value, and exposing the property in debugFillProperties for debugging.

gemini-code-assist · 2026-06-19T13:37:55Z

    this.side,
    this.isError = false,
    this.semanticLabel,
+    this.padding,


Since Checkbox.adaptive delegates to CupertinoCheckbox on iOS and macOS, and CupertinoCheckbox does not currently support a padding property, this padding will be ignored on those platforms. Please document this platform-specific behavior in the padding property's API documentation or the Checkbox.adaptive constructor documentation so developers are aware of this limitation.

The documentation update regarding the platform-specific behavior of Checkbox.adaptive is appreciated. I noticed a small issue in packages/flutter/lib/src/material/checkbox_theme.dart: there is a duplicate line in debugFillProperties where side is added twice. Please remove the redundant line.

Suggested change

this.padding,

properties.add(DiagnosticsProperty<BorderSide>('side', side, defaultValue: null));

properties.add(DiagnosticsProperty<EdgeInsetsGeometry>('padding', padding, defaultValue: null));

/gemini review

The code changes in this pull request correctly implement the padding property for the Checkbox widget. The implementation properly handles the resolvedPadding against the ambient Directionality, updates the _CheckboxPainter to use the padding for the check mark and indeterminate dash, and includes comprehensive tests covering edge cases and theme interactions. The documentation also correctly addresses the platform-specific limitation for Checkbox.adaptive on iOS and macOS. The redundant line in debugFillProperties has been removed as requested.

gemini-code-assist · 2026-06-19T13:37:55Z

  /// {@endtemplate}
  final String? semanticLabel;

+  /// The padding around the check mark when the checkbox is checked or


To support global styling and consistent theming across the application, the padding property should also be added to CheckboxThemeData in checkbox_theme.dart and resolved here (e.g., widget.padding ?? checkboxTheme.padding ?? EdgeInsets.zero).

gemini-code-assist · 2026-06-19T13:37:55Z

+  /// Defaults to [EdgeInsets.zero], which renders the check mark at its full
+  /// size (the same as before this property existed).
+  final EdgeInsetsGeometry? padding;


The documentation states Defaults to [EdgeInsets.zero], but the actual property value defaults to null (which is then resolved to EdgeInsets.zero internally). To be precise and follow Flutter's documentation standards, please clarify this.

For example:
Defaults to null, which resolves to [EdgeInsets.zero].

/// Defaults to null, which resolves to [EdgeInsets.zero], rendering the /// check mark at its full size (the same as before this property existed). final EdgeInsetsGeometry? padding;

Piinks · 2026-06-24T18:58:45Z

I've marked this PR as not ready to port to flutter/packages yet.
We'll provide instructions to move this change over to material_ui once it is ready to receive PRs. Thank you!

QuncCccccc

I think calling the property padding might be a bit misleading. For example, the existing IconButton.padding and Switch.padding can affect the overall size of IconButton and Switch, however, this PR change seems only adjust the size of the checkmark and location inside the checkbox.

Maybe we can rename it to something like markInsets? Or let me know if there are a better name.

QuncCccccc · 2026-07-22T00:42:56Z

+    expect(_checkboxRenderer(tester), paints..path(strokeWidth: 1.0));
+  });
+
+  testWidgets('Checkbox.padding shrinks the indeterminate dash too', (WidgetTester tester) async {


nit:

Suggested change

testWidgets('Checkbox.padding shrinks the indeterminate dash too', (WidgetTester tester) async {

testWidgets('Checkbox.padding shrinks the indeterminate dash', (WidgetTester tester) async {

QuncCccccc · 2026-07-22T00:47:49Z

+  /// Must be non-negative. Padding larger than the box collapses the check
+  /// mark to nothing.


Suggested change

/// Must be non-negative. Padding larger than the box collapses the check

/// mark to nothing.

/// Must be non-negative. If the resolved horizontal or vertical padding is

/// greater than or equal to the checkbox size, the check mark or indeterminate

/// dash is not painted..

QuncCccccc · 2026-07-22T00:52:55Z

  State<Checkbox> createState() => _CheckboxState();
+
+  @override
+  void debugFillProperties(DiagnosticPropertiesBuilder properties) {


Checkbox did not previously expose its existing widget properties through debugFillProperties. Adding an override only for the new padding property makes diagnostics oddly incomplete. I think in this PR, it is okay to not override debugFillProperties.

QuncCccccc · 2026-07-22T01:04:02Z

+  /// If null, [CheckboxThemeData.padding] is used. If that is also null,
+  /// it defaults to [EdgeInsets.zero] and the check mark renders at full size.
+  /// {@endtemplate}
+  final EdgeInsetsGeometry? padding;


Maybe EdgeInsets? would be enough, so that we don't need .resolve(Directionality.maybeOf(context));? Because I think the most common case would be making the check mark or dash be centered. We don't really need to care about the directionality?

QuncCccccc · 2026-07-22T01:04:44Z

+    final EdgeInsets resolvedPadding = (widget.padding ?? checkboxTheme.padding ?? EdgeInsets.zero)
+        .resolve(Directionality.maybeOf(context));
+
+    assert(resolvedPadding.isNonNegative, 'Checkbox.padding cannot be negative.');


nit: I think no need to add this to keep consistency with other EdgeInsets use case.

fluttergithubbot · 2026-07-22T06:49:24Z

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Munawer-Ali · 2026-07-22T07:23:47Z

Thanks for the review, @QuncCccccc ! I've addressed all the comments:

Renamed padding → markInsets (on both Checkbox and CheckboxThemeData) to avoid implying it changes the overall widget size.
Changed the type to EdgeInsets? and removed the .resolve(Directionality...) since directionality isn't needed here.
Removed the assert for consistency with other EdgeInsets usages.
Removed the debugFillProperties override — agreed it's inconsistent to expose only this one property.
Updated the doc wording and the test name as suggested.

Let me know if markInsets works as the final name or if you'd prefer something else. Ready for another look when you have time.

QuncCccccc

Thanks a lot for your contribution! Overall it looks really good. Just left a few comments below.

QuncCccccc · 2026-07-22T21:29:43Z

+  /// effect, because the checkbox delegates to [CupertinoCheckbox], which does
+  /// not support insets.
+  ///
+  /// Must be non-negative. If the resolved horizontal or vertical insets are


Suggested change

/// Must be non-negative. If the resolved horizontal or vertical insets are

/// Must be non-negative. If the horizontal or vertical insets are

QuncCccccc · 2026-07-22T21:34:03Z

@@ -641,6 +666,7 @@ class _CheckboxState extends State<Checkbox> with TickerProviderStateMixin, Togg
          ..previousValue = _previousValue
          ..shape = widget.shape ?? checkboxTheme.shape ?? defaults.shape!
          ..activeSide = activeSide
+          ..padding = markInsets


Do we also consider to rename _CheckboxPainter.padding to markInsets for consistency?

Munawer-Ali · 2026-07-23T09:03:25Z

@QuncCccccc Thanks! Both addressed in the latest push:

Renamed _CheckboxPainter.padding → markInsets for consistency.
Updated the doc wording (removed "resolved").

Let me know if there's anything else.

dkwingsmt

LGTM. Thank you!

QuncCccccc

Overall LGTM with just one more doc comment. Thanks again for your contribution:)!

QuncCccccc · 2026-07-23T17:43:20Z

+  /// is not affected. The check mark and its stroke shrink to fit the
+  /// remaining space, so the mark stays proportional.
+  ///
+  /// On iOS and macOS, when using [Checkbox.adaptive], this property has no


Since this is ignored in Checkbox.adaptive, can we also add this property name in the doc here - it lists all properties that are ignored in Checkbox.adaptive.

Done — added markInsets to the list of parameters ignored by Checkbox.adaptive. Please take a look and let me know if anything else is needed. Thanks again!

QuncCccccc

LGTM! Thanks again for your contribution!

Munawer-Ali · 2026-07-24T10:40:10Z

@QuncCccccc @dkwingsmt Thanks for the review and approval! I see the PR is blocked by the Material code freeze (
#184093) since it touches packages/flutter/lib/src/material. Should I port this markInsets change to the material_ui package in flutter/packages? If so, is there anything from this PR I should carry over or link? Happy to open it there.

Piinks · 2026-07-24T17:26:41Z

Hey @Munawer-Ali thanks for the contribution! This will need to be moved over to flutter/packages and the new material_ui package, but we're not quite ready to accept PRs yet. Let's leave this here, and we will let you know when to move it over with instructions when it is ready. :)

Munawer-Ali · 2026-07-25T18:19:39Z

Thank you! The Flutter team has been really welcoming and supportive throughout — great and sweet people. 🙂 I'll leave the PR here and wait for your instructions to move it over to material_ui when it's ready. Appreciate all the help!

dkwingsmt · 2026-07-29T18:15:38Z

Thanks for your contribution! This PR has reached completion, however we're not able to merge this PR for the moment due to the Material/Cupertino code freeze (#184093). As soon as the decoupling is complete, we will post a way to port this PR to the new packages to land. In the meantime, I'll convert this PR to a draft and apply a label so that we can quickly find it when the freeze is lifted.

victorsanni · 2026-07-29T18:16:36Z

-    const start = Offset(_kEdgeSize * 0.15, _kEdgeSize * 0.45);
-    const mid = Offset(_kEdgeSize * 0.4, _kEdgeSize * 0.7);
-    const end = Offset(_kEdgeSize * 0.85, _kEdgeSize * 0.25);
+    final double innerW = (_kEdgeSize - _markInsets.horizontal).clamp(0.0, _kEdgeSize);


Use clampDouble instead (here and everywhere else in this PR) to pass CI (linux analyze)

Munawer-Ali · 2026-08-30T07:30:49Z

Hello @Piinks ma’am, can I port those changes to the Material UI package?

dkwingsmt · 2026-08-30T07:40:14Z

Yes, please! (We've been sending port notifications to pending PRs in batches to avoid having too many new PRs at once, but sending yours now is very welcome!) Guidance and instructions for easily porting over can be found in #188444. Thank you!

github-actions · 2026-08-30T08:58:01Z

This pull request contains changes to Material or Cupertino, which are currently frozen in this repository.

Changes should be made in material_ui and/or cupertino_ui in the flutter/packages repository.

Please refer to #188444 for instructions.

Munawer-Ali · 2026-08-30T11:20:20Z

I moved my changes to flutter/packages:
flutter/packages#12690
Closing this one. Thanks @QuncCccccc @Piinks @dkwingsmt @victorsanni

This PR ports my changes from flutter/flutter#188258 to flutter/packages, as part of flutter/flutter#188444 Adds `Checkbox.markInsets` and `CheckboxThemeData.markInsets`, which inset the check mark and the indeterminate dash within the checkbox without changing the size of the box itself. The mark and its stroke shrink proportionally, and the mark is not painted if the insets leave no room. Fixes flutter/flutter#188031 ## Tests Added to `packages/material_ui/test/checkbox_test.dart`: - `Checkbox.markInsets` defaults to null - Checkbox with no `markInsets` paints the check at full stroke width (backward-compat) - `Checkbox.markInsets` shrinks the check mark and its stroke - `Checkbox.markInsets` shrinks the indeterminate dash - `Checkbox.markInsets` larger than the box collapses the mark without crashing - `Checkbox.markInsets` falls back to `CheckboxThemeData.markInsets` - `Checkbox.markInsets` overrides `CheckboxThemeData.markInsets` ## Pre-Review Checklist submitting PRs. am not using AI tools. brackets, e.g. `[shared_preferences]` and the [repository CHANGELOG style], or I have commented below to indicate which documented exception this PR falls under[^1]. indicate which [test exemption] this PR falls under[^1]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. [^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

github-actions Bot added framework flutter/packages/flutter repository. See also f: labels. p: material_ui material_ui package in flutter/packages labels Jun 19, 2026

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Munawer-Ali force-pushed the checkbox-padding branch from 3ffc553 to 7684fd3 Compare June 19, 2026 14:33

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QuncCccccc self-requested a review July 22, 2026 16:52

QuncCccccc changed the title ~~Add padding property to Checkbox~~ Add markInsets property to Checkbox Jul 22, 2026

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coderabbitai Bot mentioned this pull request Aug 4, 2026

theme: three-tier design tokens with light and dark bindings momshaddinury/flutter_template#60

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Munawer-Ali added 6 commits August 30, 2026 13:37

Add padding property to Checkbox

5d97f4e

Add Checkbox.padding theme support, docs, and debugFillProperties

7660c2d

Remove duplicate side property in CheckboxThemeData.debugFillProperties

f77120b

Rename Checkbox.padding to markInsets and address review feedback

cca99f6

Address review: rename painter field to markInsets, fix doc wording

cace053

Doc: list markInsets among parameters ignored by Checkbox.adaptive

5618b50

Munawer-Ali dismissed stale reviews from dkwingsmt and QuncCccccc via c1be6d9 August 30, 2026 08:57

Munawer-Ali force-pushed the checkbox-padding branch from 06fe467 to c1be6d9 Compare August 30, 2026 08:57

flutter-dashboard Bot removed the CICD Run CI/CD label Aug 30, 2026

Use clampDouble instead of double.clamp to pass linux analyze

0f8d97d

Munawer-Ali force-pushed the checkbox-padding branch from c1be6d9 to 0f8d97d Compare August 30, 2026 09:11

Munawer-Ali mentioned this pull request Aug 30, 2026

[material_ui] Add Checkbox.markInsets flutter/packages#12690

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Munawer-Ali closed this Aug 30, 2026

	this.padding,
	properties.add(DiagnosticsProperty<BorderSide>('side', side, defaultValue: null));
	properties.add(DiagnosticsProperty<EdgeInsetsGeometry>('padding', padding, defaultValue: null));

	testWidgets('Checkbox.padding shrinks the indeterminate dash too', (WidgetTester tester) async {
	testWidgets('Checkbox.padding shrinks the indeterminate dash', (WidgetTester tester) async {

		/// Must be non-negative. Padding larger than the box collapses the check
		/// mark to nothing.

-  /// Must be non-negative. Padding larger than the box collapses the check
-  /// mark to nothing.
+  /// Must be non-negative. If the resolved horizontal or vertical padding is
+  /// greater than or equal to the checkbox size, the check mark or indeterminate
+  /// dash is not painted..

	/// Must be non-negative. If the resolved horizontal or vertical insets are
	/// Must be non-negative. If the horizontal or vertical insets are

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Munawer-Ali commented Jun 19, 2026 •

edited by QuncCccccc

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