[mathml] Take lspace/rspace into account in row layout

When laying out rows [1] lspace and rspace values from operators
need to be taken into account. Since we did not introduce
embellished operators yet, this CL just takes into account
row children that are of type <mo> [2].

[1] https://mathml-refresh.github.io/mathml-core/#layout-of-mrow
[2] https://mathml-refresh.github.io/mathml-core/#dfn-embellished-operator

Bug: 6606
Change-Id: I35cb69724fa58f39c18511ce13ec941f5536a7bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2390652
Commit-Queue: Rob Buis <rbuis@igalia.com>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Reviewed-by: Frédéric Wang <fwang@igalia.com>
Cr-Commit-Position: refs/heads/master@{#804793}

third_party/blink/renderer/core/layout/ng/mathml/ng_math_layout_utils.cc

@@ -126,11 +126,11 @@ RadicalHorizontalParameters GetRadicalHorizontalParameters(
   parameters.kern_before_degree = LayoutUnit(
       MathConstant(style,
                    OpenTypeMathSupport::MathConstants::kRadicalKernBeforeDegree)
-          .value_or(5 * style.FontSize() / 18));
+          .value_or(5 * style.FontSize() * kMathUnitFraction));
   parameters.kern_after_degree = LayoutUnit(
       MathConstant(style,
                    OpenTypeMathSupport::MathConstants::kRadicalKernAfterDegree)
-          .value_or(-10 * style.FontSize() / 18));
+          .value_or(-10 * style.FontSize() * kMathUnitFraction));
   return parameters;
 }
 

third_party/blink/renderer/core/layout/ng/mathml/ng_math_row_layout_algorithm.cc

@@ -12,6 +12,7 @@
 #include "third_party/blink/renderer/core/layout/ng/ng_out_of_flow_layout_part.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_physical_box_fragment.h"
 #include "third_party/blink/renderer/core/mathml/mathml_element.h"
+#include "third_party/blink/renderer/core/mathml/mathml_operator_element.h"
 
 namespace blink {
 namespace {
@@ -25,6 +26,26 @@ inline LayoutUnit InlineOffsetForDisplayMathCentering(
   return LayoutUnit();
 }
 
+static void DetermineOperatorSpacing(const NGLayoutInputNode& node,
+                                     LayoutUnit* lspace,
+                                     LayoutUnit* rspace) {
+  auto* core_operator =
+      DynamicTo<MathMLOperatorElement>(node.GetLayoutBox()->GetNode());
+  if (core_operator) {
+    // TODO(crbug.com/1124298): Implement embellished operators.
+    LayoutUnit leading_space(core_operator->DefaultLeadingSpace() *
+                             node.Style().FontSize());
+    *lspace = std::max<LayoutUnit>(
+        ValueForLength(node.Style().GetMathLSpace(), leading_space),
+        LayoutUnit());
+    LayoutUnit trailing_space(core_operator->DefaultTrailingSpace() *
+                              node.Style().FontSize());
+    *rspace = std::max<LayoutUnit>(
+        ValueForLength(node.Style().GetMathRSpace(), trailing_space),
+        LayoutUnit());
+  }
+}
+
 }  // namespace
 
 NGMathRowLayoutAlgorithm::NGMathRowLayoutAlgorithm(
@@ -51,6 +72,8 @@ void NGMathRowLayoutAlgorithm::LayoutRowItems(
           To<NGBlockNode>(child), BorderScrollbarPadding().StartOffset());
       continue;
     }
+    LayoutUnit lspace, rspace;
+    DetermineOperatorSpacing(child, &lspace, &rspace);
     const ComputedStyle& child_style = child.Style();
     NGConstraintSpace child_space = CreateConstraintSpaceForMathChild(
         Node(), ChildAvailableSize(), ConstraintSpace(), child);
@@ -70,7 +93,7 @@ void NGMathRowLayoutAlgorithm::LayoutRowItems(
     *max_row_block_baseline = std::max(*max_row_block_baseline, ascent);
 
     // TODO(crbug.com/1125136): take into account italic correction.
-    // TODO(rbuis): Operators can add lspace and rspace.
+    inline_offset += lspace;
 
     children->emplace_back(
         To<NGBlockNode>(child), margins,
@@ -79,6 +102,8 @@ void NGMathRowLayoutAlgorithm::LayoutRowItems(
 
     inline_offset += fragment.InlineSize() + margins.inline_end;
 
+    inline_offset += rspace;
+
     max_row_ascent = std::max(max_row_ascent, ascent + margins.block_start);
     max_row_descent = std::max(
         max_row_descent, fragment.BlockSize() + margins.block_end - ascent);
@@ -150,11 +175,14 @@ MinMaxSizesResult NGMathRowLayoutAlgorithm::ComputeMinMaxSizes(
     child_result.sizes += child_margins.InlineSum();
 
     sizes += child_result.sizes;
+
+    LayoutUnit lspace, rspace;
+    DetermineOperatorSpacing(child, &lspace, &rspace);
+    sizes += lspace + rspace;
     depends_on_percentage_block_size |=
         child_result.depends_on_percentage_block_size;
 
     // TODO(crbug.com/1125136): take into account italic correction.
-    // TODO(rbuis): Operators can add lspace and rspace.
   }
 
   // Due to negative margins, it is possible that we calculated a negative

third_party/blink/renderer/core/mathml/mathml_operator_element.cc

@@ -279,4 +279,24 @@ void MathMLOperatorElement::AddMathMaxSizeIfNeeded(
   }
 }
 
+double MathMLOperatorElement::DefaultLeadingSpace() {
+  ComputeDictionaryCategory();
+  return static_cast<float>(
+             MathMLOperatorDictionaryCategories
+                 [std::underlying_type_t<MathMLOperatorDictionaryCategory>(
+                      properties_.dictionary_category)]
+                     .leading_space_in_math_unit) *
+         kMathUnitFraction;
+}
+
+double MathMLOperatorElement::DefaultTrailingSpace() {
+  ComputeDictionaryCategory();
+  return static_cast<float>(
+             MathMLOperatorDictionaryCategories
+                 [std::underlying_type_t<MathMLOperatorDictionaryCategory>(
+                      properties_.dictionary_category)]
+                     .trailing_space_in_math_unit) *
+         kMathUnitFraction;
+}
+
 }  // namespace blink

third_party/blink/renderer/core/mathml/mathml_operator_element.h

@@ -15,6 +15,9 @@ class Document;
 
 enum class MathMLOperatorDictionaryCategory : uint8_t;
 
+// Math units are 1/18em.
+constexpr double kMathUnitFraction = 1.0 / 18.0;
+
 class CORE_EXPORT MathMLOperatorElement final : public MathMLElement {
  public:
   explicit MathMLOperatorElement(Document&);
@@ -38,6 +41,9 @@ class CORE_EXPORT MathMLOperatorElement final : public MathMLElement {
   void AddMathMaxSizeIfNeeded(ComputedStyle&, const CSSToLengthConversionData&);
   const OperatorContent& GetOperatorContent();
 
+  double DefaultLeadingSpace();
+  double DefaultTrailingSpace();
+
  private:
   base::Optional<OperatorContent> operator_content_;
   // Operator properties calculated from dictionary and attributes.

third_party/blink/web_tests/TestExpectations

@@ -1247,13 +1247,9 @@ crbug.com/6606 external/wpt/mathml/presentation-markup/mrow/legacy-mrow-like-ele
 crbug.com/6606 external/wpt/mathml/presentation-markup/mrow/legacy-mrow-like-elements-002.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/operators/mo-axis-height-1.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/operators/mo-form-dynamic.html [ Failure ]
-crbug.com/6606 external/wpt/mathml/presentation-markup/operators/mo-form-minus-plus.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/operators/mo-form.html [ Failure ]
-crbug.com/6606 external/wpt/mathml/presentation-markup/operators/mo-not-in-dictionary-lspace-rspace.html [ Failure ]
-crbug.com/6606 external/wpt/mathml/presentation-markup/operators/mo-paint-lspace-rspace.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/spaces/space-like-001.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/spaces/space-like-002.html [ Failure ]
-crbug.com/6606 external/wpt/mathml/presentation-markup/spaces/space-like-003.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/tables/table-001.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/tables/table-002.html [ Failure ]
 crbug.com/6606 external/wpt/mathml/presentation-markup/tables/table-axis-height.html [ Failure ]
@@ -2604,10 +2600,8 @@ crbug.com/626703 external/wpt/service-workers/service-worker/global-serviceworke
 crbug.com/626703 external/wpt/workers/examples/onconnect.any.worker.html [ Timeout ]
 crbug.com/626703 external/wpt/cookie-store/serviceworker_oncookiechange_eventhandler_single_subscription.tentative.https.any.worker.html [ Timeout ]
 crbug.com/626703 external/wpt/workers/postMessage_block.https.html [ Timeout ]
-crbug.com/626703 external/wpt/mathml/relations/css-styling/color-005.html [ Failure ]
 crbug.com/626703 external/wpt/content-security-policy/script-src/script-src-strict_dynamic_double_policy_honor_source_expressions.html [ Timeout ]
 crbug.com/626703 external/wpt/uievents/order-of-events/focus-events/focus-management-expectations.html [ Timeout ]
-crbug.com/626703 external/wpt/mathml/presentation-markup/operators/mo-form-dynamic-002.html [ Failure ]
 crbug.com/626703 external/wpt/mathml/presentation-markup/operators/mo-lspace-rspace-dynamic.html [ Failure ]
 crbug.com/626703 [ Mac10.14 ] external/wpt/webrtc/RTCRtpSender-replaceTrack.https.html [ Timeout ]
 crbug.com/626703 [ Win ] external/wpt/webrtc/RTCRtpSender-replaceTrack.https.html [ Timeout ]

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/mrow/mrow-preferred-width-expected.txt

 This is a testharness.js-based test.
 FAIL Preferred width of mrow with mspace children assert_approx_equals: unknown expected 15 +/- 1 but got 30
-FAIL Preferred width of mrow with mn and mo children assert_true: expected true got false
+PASS Preferred width of mrow with mn and mo children
 Harness: the test ran to completion.
 

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/mrow/no-spacing-expected.txt

 This is a testharness.js-based test.
-FAIL Spacing inside <mfrac>. assert_true: expected true got false
-FAIL Spacing around <mfrac>. assert_true: expected true got false
-FAIL Spacing inside <msub>. assert_true: expected true got false
-FAIL Spacing around <msub>. assert_true: expected true got false
-FAIL Spacing inside <msup>. assert_true: expected true got false
-FAIL Spacing around <msup>. assert_true: expected true got false
-FAIL Spacing inside <msubsup>. assert_true: expected true got false
-FAIL Spacing around <msubsup>. assert_true: expected true got false
-FAIL Spacing inside <mmultiscripts>. assert_true: expected true got false
-FAIL Spacing around <mmultiscripts>. assert_true: expected true got false
-FAIL Spacing inside <munder>. assert_true: expected true got false
-FAIL Spacing around <munder>. assert_true: expected true got false
-FAIL Spacing inside <mover>. assert_true: expected true got false
-FAIL Spacing around <mover>. assert_true: expected true got false
-FAIL Spacing inside <munderover>. assert_true: expected true got false
-FAIL Spacing around <munderover>. assert_true: expected true got false
-FAIL Spacing inside <mroot>. assert_true: expected true got false
-FAIL Spacing around <mroot>. assert_true: expected true got false
+PASS Spacing inside <mfrac>.
+FAIL Spacing around <mfrac>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 27
+PASS Spacing inside <msub>.
+FAIL Spacing around <msub>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 55
+PASS Spacing inside <msup>.
+FAIL Spacing around <msup>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 55
+PASS Spacing inside <msubsup>.
+FAIL Spacing around <msubsup>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 55
+PASS Spacing inside <mmultiscripts>.
+FAIL Spacing around <mmultiscripts>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 85
+PASS Spacing inside <munder>.
+FAIL Spacing around <munder>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 25
+PASS Spacing inside <mover>.
+FAIL Spacing around <mover>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 25
+PASS Spacing inside <munderover>.
+FAIL Spacing around <munderover>. assert_greater_than_equal: expected a number greater than or equal to 200 but got 25
+FAIL Spacing inside <mroot>. assert_less_than_equal: expected a number less than or equal to 100 but got 106.9375
+FAIL Spacing around <mroot>. assert_less_than_equal: expected a number less than or equal to 100 but got 106.9375
 Harness: the test ran to completion.
 

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/mrow/spacing-expected.txt

 This is a testharness.js-based test.
-FAIL operator spacing inside Mrow assert_true: expected true got false
-FAIL operator spacing inside Sqrt assert_true: expected true got false
-FAIL operator spacing inside Style assert_true: expected true got false
-FAIL operator spacing inside Error assert_true: expected true got false
-FAIL operator spacing inside Phantom assert_true: expected true got false
-FAIL operator spacing inside Math assert_true: expected true got false
-FAIL operator spacing inside Menclose assert_true: expected true got false
-FAIL operator spacing inside Mpadded assert_true: expected true got false
-FAIL operator spacing inside Unknown assert_true: expected true got false
+PASS operator spacing inside Mrow
+PASS operator spacing inside Sqrt
+PASS operator spacing inside Style
+PASS operator spacing inside Error
+PASS operator spacing inside Phantom
+PASS operator spacing inside Math
+FAIL operator spacing inside Menclose assert_greater_than_equal: expected a number greater than or equal to 50 but got -8
+PASS operator spacing inside Mpadded
+FAIL operator spacing inside Unknown assert_greater_than_equal: expected a number greater than or equal to 50 but got -8
 Harness: the test ran to completion.
 

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/embellished-operator-003-expected.txt

 This is a testharness.js-based test.
-FAIL maction (embellished operator) assert_true: expected true got false
-FAIL maction (embellished operator, from in-flow children) assert_true: expected true got false
-FAIL maction (not embellished operator) assert_true: expected true got false
-FAIL maction (not embellished operator, from in-flow children) assert_true: expected true got false
-FAIL maction (not embellished operator, empty) assert_true: expected true got false
-FAIL maction (embellished operator, one child) assert_true: expected true got false
-FAIL maction (embellished operator, complex) assert_true: expected true got false
-FAIL semantics (embellished operator) assert_true: expected true got false
-FAIL semantics (embellished operator, from in-flow children) assert_true: expected true got false
-FAIL semantics (not embellished operator) assert_true: expected true got false
-FAIL semantics (not embellished operator, from in-flow children) assert_true: expected true got false
-FAIL semantics (not embellished operator, empty) assert_true: expected true got false
-FAIL semantics (embellished operator, one child) assert_true: expected true got false
-FAIL semantics (embellished operator, complex) assert_true: expected true got false
+FAIL maction (embellished operator) assert_approx_equals: expected 50 +/- 1 but got 0
+FAIL maction (embellished operator, from in-flow children) assert_approx_equals: expected 50 +/- 1 but got 0
+PASS maction (not embellished operator)
+PASS maction (not embellished operator, from in-flow children)
+PASS maction (not embellished operator, empty)
+FAIL maction (embellished operator, one child) assert_approx_equals: expected 50 +/- 1 but got 0
+FAIL maction (embellished operator, complex) assert_approx_equals: expected 50 +/- 1 but got 0
+FAIL semantics (embellished operator) assert_approx_equals: expected 50 +/- 1 but got 0
+FAIL semantics (embellished operator, from in-flow children) assert_approx_equals: expected 50 +/- 1 but got 0
+PASS semantics (not embellished operator)
+PASS semantics (not embellished operator, from in-flow children)
+PASS semantics (not embellished operator, empty)
+FAIL semantics (embellished operator, one child) assert_approx_equals: expected 50 +/- 1 but got 0
+FAIL semantics (embellished operator, complex) assert_approx_equals: expected 50 +/- 1 but got 0
 Harness: the test ran to completion.
 

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/mo-font-relative-lengths-001-expected.txt

 This is a testharness.js-based test.
-FAIL font-relative lspace refers to the core operator assert_approx_equals: baseSizePx * fontScalePercent * lspaceEm expected 100 +/- 1 but got 50
-FAIL font-relative rspace refers to the core operator assert_approx_equals: baseSizePx * fontScalePercent * rspaceEm expected 400 +/- 1 but got 200
+PASS font-relative lspace refers to the core operator
+PASS font-relative rspace refers to the core operator
 FAIL font-relative minsize refers to the core operator assert_approx_equals: baseSizePx * fontScalePercent * minsizeEm expected 400 +/- 1 but got 50
 PASS font-relative maxsize refers to the core operator
 Harness: the test ran to completion.

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/operator-dictionary-combining-expected.txt

 This is a testharness.js-based test.
-FAIL Spacing around ≠ assert_true: expected true got false
-FAIL Spacing around =⃒ assert_true: expected true got false
-FAIL Spacing around |̸ assert_true: expected true got false
-FAIL Spacing around |⃒ assert_true: expected true got false
+PASS Spacing around ≠
+PASS Spacing around =⃒
+FAIL Spacing around |̸ assert_approx_equals: expected 66.65625 +/- 1 but got 26.65625
+PASS Spacing around |⃒
 Harness: the test ran to completion.
 

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/operator-dictionary-spacing-001-expected.txt

-This is a testharness.js-based test.
-FAIL Operator dictionary chunk 1 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 2 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 3 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 4 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 5 - lspace/rspace assert_true: expected true got false
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/operator-dictionary-spacing-002-expected.txt

-This is a testharness.js-based test.
-FAIL Operator dictionary chunk 1 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 2 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 3 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 4 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 5 - lspace/rspace assert_true: expected true got false
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/operator-dictionary-spacing-003-expected.txt

-This is a testharness.js-based test.
-FAIL Operator dictionary chunk 1 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 2 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 3 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 4 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 5 - lspace/rspace assert_true: expected true got false
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/operator-dictionary-spacing-004-expected.txt

-This is a testharness.js-based test.
-FAIL Operator dictionary chunk 1 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 2 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 3 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 4 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 5 - lspace/rspace assert_true: expected true got false
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/operator-dictionary-spacing-005-expected.txt

-This is a testharness.js-based test.
-FAIL Operator dictionary chunk 1 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 2 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 3 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 4 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 5 - lspace/rspace assert_true: expected true got false
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/mathml/presentation-markup/operators/operator-dictionary-spacing-006-expected.txt

-This is a testharness.js-based test.
-FAIL Operator dictionary chunk 1 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 2 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 3 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 4 - lspace/rspace assert_true: expected true got false
-FAIL Operator dictionary chunk 5 - lspace/rspace assert_true: expected true got false
-Harness: the test ran to completion.
-

third_party/blink/web_tests/platform/mac/external/wpt/mathml/presentation-markup/operators/operator-dictionary-combining-expected.txt

+This is a testharness.js-based test.
+PASS Spacing around ≠
+PASS Spacing around =⃒
+FAIL Spacing around |̸ assert_approx_equals: expected 66.65625 +/- 1 but got 26.671875
+PASS Spacing around |⃒
+Harness: the test ran to completion.
+