Fix rounding error for line break.

Bug: 183128727
Test: minikin_test
Change-Id: Ie36562e805d9844bdba1c16ecc7aab8a51c04ab4

2 files changed, 28 insertions, 1 deletions

diff --git a/libs/minikin/GreedyLineBreaker.cpp b/libs/minikin/GreedyLineBreaker.cpp
index f6952a9..9bcb22d 100644
--- a/libs/minikin/GreedyLineBreaker.cpp
+++ b/libs/minikin/GreedyLineBreaker.cpp
@@ -255,7 +255,7 @@ bool GreedyLineBreaker::tryLineBreakWithHyphenation(const Range& range, WordBrea
 
 // TODO: Respect trailing line end spaces.
 bool GreedyLineBreaker::doLineBreakWithGraphemeBounds(const Range& range) {
-    double width = mMeasuredText.widths[range.getStart()];
+    float width = mMeasuredText.widths[range.getStart()];
 
     // Starting from + 1 since at least one character needs to be assigned to a line.
     for (uint32_t i = range.getStart() + 1; i < range.getEnd(); ++i) {
diff --git a/tests/unittest/GreedyLineBreakerTest.cpp b/tests/unittest/GreedyLineBreakerTest.cpp
index 13cc03c..e9da1a1 100644
--- a/tests/unittest/GreedyLineBreakerTest.cpp
+++ b/tests/unittest/GreedyLineBreakerTest.cpp
@@ -93,6 +93,33 @@ private:
     std::vector<uint8_t> mHyphenationPattern;
 };
 
+TEST_F(GreedyLineBreakerTest, roundingError) {
+    MeasuredTextBuilder builder;
+    auto family1 = buildFontFamily("Ascii.ttf");
+    std::vector<std::shared_ptr<FontFamily>> families = {family1};
+    auto fc = std::make_shared<FontCollection>(families);
+    MinikinPaint paint(fc);
+    paint.size = 56.0f;  // Make 1em=56px
+    paint.scaleX = 1;
+    paint.letterSpacing = -0.093f;
+    paint.localeListId = LocaleListCache::getId("en-US");
+    const std::vector<uint16_t> textBuffer = utf8ToUtf16("8888888888888888888");
+
+    float measured = Layout::measureText(textBuffer, Range(0, textBuffer.size()), Bidi::LTR, paint,
+                                         StartHyphenEdit::NO_EDIT, EndHyphenEdit::NO_EDIT, nullptr);
+
+    builder.addStyleRun(0, textBuffer.size(), std::move(paint), false);
+    std::unique_ptr<MeasuredText> measuredText =
+            builder.build(textBuffer, false /* compute hyphenation */,
+                          false /* compute full layout */, nullptr /* no hint */);
+    RectangleLineWidth rectangleLineWidth(measured);
+    TabStops tabStops(nullptr, 0, 10);
+    LineBreakResult r = breakLineGreedy(textBuffer, *measuredText, rectangleLineWidth, tabStops,
+                                        false /* do hyphenation */);
+
+    EXPECT_EQ(1u, r.breakPoints.size());
+}
+
 TEST_F(GreedyLineBreakerTest, testBreakWithoutHyphenation) {
     constexpr bool NO_HYPHEN = false;  // No hyphenation in this test case.
     const std::vector<uint16_t> textBuf = utf8ToUtf16("This is an example text.");