Break layout context before and after bidi control character

Bug: 170968514
Test: minikin_test
Change-Id: Ibcff6f3b7fcb7fefa2acb7f52446cf4b4547a4a2
Merged-In: Ibcff6f3b7fcb7fefa2acb7f52446cf4b4547a4a2
(cherry picked from commit b0473792a5a0d9d287f6995f27e867c074835a28)

2 files changed, 40 insertions, 0 deletions

diff --git a/libs/minikin/LayoutUtils.cpp b/libs/minikin/LayoutUtils.cpp
index 3c258cf..acf07e2 100644
--- a/libs/minikin/LayoutUtils.cpp
+++ b/libs/minikin/LayoutUtils.cpp
@@ -36,6 +36,11 @@ static bool isWordBreakAfter(uint16_t c) {
         // spaces
         return true;
     }
+    // Break layout context before and after BiDi control character.
+    if ((0x2066 <= c && c <= 0x2069) || (0x202A <= c && c <= 0x202E) || c == 0x200E ||
+        c == 0x200F) {
+        return true;
+    }
     // Note: kana is not included, as sophisticated fonts may kern kana
     return false;
 }
diff --git a/tests/unittest/LayoutSplitterTest.cpp b/tests/unittest/LayoutSplitterTest.cpp
index 4b75d9c..9b88de0 100644
--- a/tests/unittest/LayoutSplitterTest.cpp
+++ b/tests/unittest/LayoutSplitterTest.cpp
@@ -323,5 +323,40 @@ TEST(LayoutSplitterTest, RTL_CJK) {
     }
 }
 
+TEST(LayoutSplitterTest, BidiCtrl) {
+    struct TestCase {
+        std::string testStr;
+        std::vector<std::string> expects;
+    } testCases[] = {
+            {// Repeated Bidi sequence
+             "(a\u2066\u2069\u202A\u202E\u200E\u200Fb)",
+             {
+                     "[(a)]\u2066\u2069\u202A\u202E\u200E\u200Fb",
+                     "a[(\u2066)]\u2069\u202A\u202E\u200E\u200Fb",
+                     "a\u2066[(\u2069)]\u202A\u202E\u200E\u200Fb",
+                     "a\u2066\u2069[(\u202A)]\u202E\u200E\u200Fb",
+                     "a\u2066\u2069\u202A[(\u202E)]\u200E\u200Fb",
+                     "a\u2066\u2069\u202A\u202E[(\u200E)]\u200Fb",
+                     "a\u2066\u2069\u202A\u202E\u200E[(\u200F)]b",
+                     "a\u2066\u2069\u202A\u202E\u200E\u200F[(b)]",
+             }},
+    };
+
+    for (const auto& testCase : testCases) {
+        auto [text, range] = parseTestString(testCase.testStr);
+        uint32_t expectationIndex = 0;
+        for (auto [acContext, acPiece] : LayoutSplitter(text, range, false /* isRtl */)) {
+            ASSERT_NE(expectationIndex, testCase.expects.size());
+            const std::string expectString = testCase.expects[expectationIndex++];
+            auto [exContext, exPiece] = parseExpectString(expectString);
+            EXPECT_EQ(acContext, exContext)
+                    << expectString << " vs " << buildDebugString(text, acContext, acPiece);
+            EXPECT_EQ(acPiece, exPiece)
+                    << expectString << " vs " << buildDebugString(text, acContext, acPiece);
+        }
+        EXPECT_EQ(expectationIndex, testCase.expects.size()) << "Expectations Remains";
+    }
+}
+
 }  // namespace
 }  // namespace minikin