Adds sdf rrects (and fixes opacity + color source) by gaaclarke · Pull Request #184999 · flutter/flutter

gaaclarke · 2026-04-13T21:05:23Z

This also fixes a bug in the color source rendering where if the opacity was something other than 1.0 the opacity value would get doubled. This is avoided by overwriting the opacity value used by the uber sdf.

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gaaclarke · 2026-04-13T22:45:26Z

+  const RoundingRadii& radii = round_rect.GetRadii();
+
+  if (renderer_.GetContext()->GetFlags().use_sdfs &&
+      !paint.mask_blur_descriptor.has_value() && AreCornersCircular(radii)) {


I'll file a followup issue for non-circular corners. I'm not sure how high of a priority that is though.

gaaclarke · 2026-04-13T22:46:41Z

The crosses in FilledRoundRectPathsRenderCorrectly look much more transparent when drawn with the ubersdf shader.

gaaclarke · 2026-04-14T17:35:11Z

The differences in the colors has to do with drawing things when the paint has opacity (ex paint.setColor(DlColor::kWhite().modulateOpacity(0.5));)

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Code Review

This pull request adds rounded rectangle support to the UberSDF renderer by implementing distanceFromRoundedRect in the fragment shader and updating Canvas::DrawRoundRect to use SDF rendering for circular corners. It also refactors AddRenderSDFEntityToCurrentPass to use UberSDFParameters. Feedback identifies a mismatch in corner radii mapping in Canvas::DrawRoundRect and requests the removal of an unnecessary newline in the shader.

walley892

Couple of comments

gaaclarke · 2026-04-14T20:54:14Z

+// https://www.youtube.com/c/InigoQuilez
+// https://iquilezles.org
+
+float distanceFromRoundedRect(in vec2 p, in vec2 b, in vec4 r) {


In a followup PR I think we should sort these out into their own file, sdf.glsl.

b-luk · 2026-04-14T23:13:38Z

+bool AreCornersCircular(const RoundingRadii& radii) {
+  return ScalarNearlyEqual(radii.top_left.width, radii.top_left.height) &&
+         ScalarNearlyEqual(radii.top_right.width, radii.top_right.height) &&
+         ScalarNearlyEqual(radii.bottom_left.width, radii.bottom_left.height) &&
+         ScalarNearlyEqual(radii.bottom_right.width, radii.bottom_right.height);
+}
+


Should this be a method on RoundingRadii like other similar methods?

flutter/engine/src/flutter/impeller/geometry/rounding_radii.h

Lines 47 to 61 in 2c50daf

constexpr bool AreAllCornersEmpty() const {

return top_left.IsEmpty() && //

top_right.IsEmpty() && //

bottom_left.IsEmpty() && //

bottom_right.IsEmpty();

}

constexpr bool AreAllCornersSame(Scalar tolerance = kEhCloseEnough) const {

return ScalarNearlyEqual(top_left.width, top_right.width, tolerance) &&

ScalarNearlyEqual(top_left.width, bottom_right.width, tolerance) &&

ScalarNearlyEqual(top_left.width, bottom_left.width, tolerance) &&

ScalarNearlyEqual(top_left.height, top_right.height, tolerance) &&

ScalarNearlyEqual(top_left.height, bottom_right.height, tolerance) &&

ScalarNearlyEqual(top_left.height, bottom_left.height, tolerance);

}

?

The rule of thumb I kind of follow is that if there is only one client to a function it's better to keep it a free function, if there are more than one then put it in the class. That avoids class bloat.

gaaclarke · 2026-04-17T16:42:02Z

One golden looked goofy: impeller_Play_AiksTest_FilledEllipsesRenderCorrectly_MetalSDF. This looks like the problem we had with rrects. Since we had merge conflicts i can take a quick peek otherwise follow up in a different PR.

before

after

gaaclarke · 2026-04-17T16:48:58Z

One golden looked goofy: impeller_Play_AiksTest_FilledEllipsesRenderCorrectly_MetalSDF. This looks like the problem we had with rrects. Since we had merge conflicts i can take a quick peek otherwise follow up in a different PR.

Okay, turns out this actually is fixing the test. We previously accepted a failure. We need to remove that golden after this lands.

gaaclarke · 2026-04-17T16:55:22Z

@b-luk @walley892 flar's refactor happened to collide with my PR before it landed so I'm coming to you yet again, hat in hand, to ask for a review. The only difference is it uses flar's GetStroke function.

b-luk · 2026-04-17T16:56:25Z

Okay, turns out this actually is fixing the test. We previously accepted a failure. We need to remove that golden after this lands.

Yes, all the different positive goldens make the diffs confusing. Should we actively try to mark every previous golden as untriaged whenever we merge a PR that updates a golden?

gaaclarke · 2026-04-17T16:58:25Z

Yes, all the different positive goldens make the diffs confusing. Should we actively try to mark every previous golden as untriaged whenever we merge a PR that updates a golden?

That's not an absolute rule of thumb. When the baseline of what is acceptable is changing we should. For flux like with blurs and gradients where they look the same to the human eye, no.

walley892 · 2026-04-17T18:55:22Z

The impeller_Play_AiksTest_FilledEllipsesRenderCorrectly_MetalSDF golden was changed by the oval PR #184903. This PR correctly fixes the alpha.

…/flutter#184999)

flutter/flutter@8e8a194...2844af6 2026-04-19 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from bWoigpGIb60B6C7hD... to aDbXQm6WA0wFCAUp-... (flutter/flutter#185253) 2026-04-18 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from di3JdYrdE9OFu8Iyl... to bWoigpGIb60B6C7hD... (flutter/flutter#185231) 2026-04-18 rmolivares@renzo-olivares.dev Fix: text selection context menu should reappear after a non-fling scroll on Android and iOS (flutter/flutter#185054) 2026-04-18 flar@google.com Rect constructors for circle bounds (MakeCircle/EllipseBounds) (flutter/flutter#185110) 2026-04-17 97480502+b-luk@users.noreply.github.com Change uber SDF to get pixel size (for AA) using euclidean distance rather than manhattan distance. (flutter/flutter#184984) 2026-04-17 engine-flutter-autoroll@skia.org Roll Dart SDK from 7c2564c18770 to 9648f446f131 (7 revisions) (flutter/flutter#185223) 2026-04-17 47866232+chunhtai@users.noreply.github.com Rewrites no-response workflow to work with pr as well (flutter/flutter#185163) 2026-04-17 15619084+vashworth@users.noreply.github.com Only use LLDB breakpoint in debug mode (flutter/flutter#185158) 2026-04-17 flar@google.com add playground to test SDF primitive rendering under transforms (flutter/flutter#185010) 2026-04-17 30870216+gaaclarke@users.noreply.github.com Adds sdf rrects (and fixes opacity + color source) (flutter/flutter#184999) 2026-04-17 matt.kosarek@canonical.com Implementation of popup windows for Win32 (flutter/flutter#184516) 2026-04-17 engine-flutter-autoroll@skia.org Roll Fuchsia Test Scripts from R2EllDf4DgBXVNuiN... to dQ4PjIJB5kZFU8Y32... (flutter/flutter#185207) 2026-04-17 chris@bracken.jp [iOS] Update previousCompositionOrder to return Obj-C type (flutter/flutter#185136) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC boetger@google.com,stuartmorgan@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

…r#11531) flutter/flutter@8e8a194...2844af6 2026-04-19 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from bWoigpGIb60B6C7hD... to aDbXQm6WA0wFCAUp-... (flutter/flutter#185253) 2026-04-18 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from di3JdYrdE9OFu8Iyl... to bWoigpGIb60B6C7hD... (flutter/flutter#185231) 2026-04-18 rmolivares@renzo-olivares.dev Fix: text selection context menu should reappear after a non-fling scroll on Android and iOS (flutter/flutter#185054) 2026-04-18 flar@google.com Rect constructors for circle bounds (MakeCircle/EllipseBounds) (flutter/flutter#185110) 2026-04-17 97480502+b-luk@users.noreply.github.com Change uber SDF to get pixel size (for AA) using euclidean distance rather than manhattan distance. (flutter/flutter#184984) 2026-04-17 engine-flutter-autoroll@skia.org Roll Dart SDK from 7c2564c18770 to 9648f446f131 (7 revisions) (flutter/flutter#185223) 2026-04-17 47866232+chunhtai@users.noreply.github.com Rewrites no-response workflow to work with pr as well (flutter/flutter#185163) 2026-04-17 15619084+vashworth@users.noreply.github.com Only use LLDB breakpoint in debug mode (flutter/flutter#185158) 2026-04-17 flar@google.com add playground to test SDF primitive rendering under transforms (flutter/flutter#185010) 2026-04-17 30870216+gaaclarke@users.noreply.github.com Adds sdf rrects (and fixes opacity + color source) (flutter/flutter#184999) 2026-04-17 matt.kosarek@canonical.com Implementation of popup windows for Win32 (flutter/flutter#184516) 2026-04-17 engine-flutter-autoroll@skia.org Roll Fuchsia Test Scripts from R2EllDf4DgBXVNuiN... to dQ4PjIJB5kZFU8Y32... (flutter/flutter#185207) 2026-04-17 chris@bracken.jp [iOS] Update previousCompositionOrder to return Obj-C type (flutter/flutter#185136) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC boetger@google.com,stuartmorgan@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

github-actions Bot added engine flutter/engine related. See also e: labels. e: impeller Impeller rendering backend issues and features requests labels Apr 13, 2026

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gaaclarke marked this pull request as ready for review April 14, 2026 18:27

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Add Superellipse SDF renderer to uber shader #183039

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Merged via the queue into flutter:master with commit 6a98710 Apr 17, 2026
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	constexpr bool AreAllCornersEmpty() const {
	return top_left.IsEmpty() && //
	top_right.IsEmpty() && //
	bottom_left.IsEmpty() && //
	bottom_right.IsEmpty();
	}

	constexpr bool AreAllCornersSame(Scalar tolerance = kEhCloseEnough) const {
	return ScalarNearlyEqual(top_left.width, top_right.width, tolerance) &&
	ScalarNearlyEqual(top_left.width, bottom_right.width, tolerance) &&
	ScalarNearlyEqual(top_left.width, bottom_left.width, tolerance) &&
	ScalarNearlyEqual(top_left.height, top_right.height, tolerance) &&
	ScalarNearlyEqual(top_left.height, bottom_right.height, tolerance) &&
	ScalarNearlyEqual(top_left.height, bottom_left.height, tolerance);
	}

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