Reset breaker after every layout to handle different widths.

Change-Id: I786c4c42b4db9418f4f802b4cbb70a051b35925a

engine/src/flutter/src/paragraph.cc

@@ -140,7 +140,9 @@ void Paragraph::SetText(std::vector<uint16_t> text, StyledRuns runs) {
     return;
   text_ = std::move(text);
   runs_ = std::move(runs);
+}
 
+void Paragraph::InitBreaker() {
   breaker_.setLocale(icu::Locale(), nullptr);
   breaker_.resize(text_.size());
   memcpy(breaker_.buffer(), text_.data(), text_.size() * sizeof(text_[0]));
@@ -182,7 +184,7 @@ void Paragraph::FillWhitespaceSet(size_t start,
 
 void Paragraph::Layout(double width, bool force) {
   // Do not allow calling layout multiple times without changing anything.
-  if (!needs_layout_ && !force && width == width_)
+  if (!needs_layout_ && width == width_ && !force)
     return;
   needs_layout_ = false;
 
@@ -199,6 +201,7 @@ void Paragraph::Layout(double width, bool force) {
   //     minikin::Hyphenator::loadBinary(<paramsgohere>);
   //   breaker_.setLocale(icu::Locale::getRoot(), &hyph);
   //
+  InitBreaker();
   AddRunsToLineBreaker(collection_map);
   breaker_.setJustified(paragraph_style_.text_align == TextAlign::justify);
   breaker_.setStrategy(paragraph_style_.break_strategy);
@@ -505,6 +508,7 @@ void Paragraph::Layout(double width, bool force) {
   line_widths_ =
       std::vector<double>(breaker_.getWidths(), breaker_.getWidths() + lines_);
   CalculateIntrinsicWidths();
+  breaker_.finish();
 }
 
 // Amends the buffers to incorporate justification.

engine/src/flutter/src/paragraph.h

@@ -163,6 +163,7 @@ class Paragraph {
   FRIEND_TEST(RenderTest, NewlineParagraph);
   FRIEND_TEST(RenderTest, EmojiParagraph);
   FRIEND_TEST(RenderTest, HyphenBreakParagraph);
+  FRIEND_TEST(RenderTest, RepeatLayoutParagraph);
 
   // Starting data to layout.
   std::vector<uint16_t> text_;
@@ -187,7 +188,7 @@ class Paragraph {
 
   // The max width of the paragraph as provided in the most recent Layout()
   // call.
-  double width_ = 0.0f;
+  double width_ = -1.0f;
   SkScalar height_ = 0.0f;
   size_t lines_ = 0;
   double max_intrinsic_width_ = 0;
@@ -207,8 +208,14 @@ class Paragraph {
         : x_start(x_s), y_start(y_s), x_end(x_e), y_end(y_e) {}
   };
 
+  // Passes in the text and Styled Runs. text_ and runs_ will later be passed
+  // into breaker_ in InitBreaker(), which is called in Layout().
   void SetText(std::vector<uint16_t> text, StyledRuns runs);
 
+  // Sets up breaker_ with the contents of text_ and runs_. This is called every
+  // Layout() call to allow for different widths to be used.
+  void InitBreaker();
+
   void SetParagraphStyle(const ParagraphStyle& style);
 
   void SetFontCollection(FontCollection* font_collection);

engine/src/flutter/src/styled_runs.h

@@ -77,6 +77,7 @@ class StyledRuns {
   FRIEND_TEST(RenderTest, LongWordParagraph);
   FRIEND_TEST(RenderTest, KernParagraph);
   FRIEND_TEST(RenderTest, HyphenBreakParagraph);
+  FRIEND_TEST(RenderTest, RepeatLayoutParagraph);
 
   struct IndexedRun {
     size_t style_index = 0;

engine/src/flutter/tests/txt/paragraph_unittests.cc

@@ -1484,4 +1484,65 @@ TEST_F(RenderTest, HyphenBreakParagraph) {
   ASSERT_TRUE(Snapshot());
 }
 
+TEST_F(RenderTest, RepeatLayoutParagraph) {
+  const char* text =
+      "Sentence to layout at diff widths to get diff line counts. short words "
+      "short words short words short words short words short words short words "
+      "short words short words short words short words short words short words";
+  auto icu_text = icu::UnicodeString::fromUTF8(text);
+  std::u16string u16_text(icu_text.getBuffer(),
+                          icu_text.getBuffer() + icu_text.length());
+
+  txt::ParagraphStyle paragraph_style;
+  paragraph_style.break_strategy = minikin::kBreakStrategy_HighQuality;
+  auto font_collection = FontCollection::GetFontCollection(txt::GetFontDir());
+  txt::ParagraphBuilder builder(paragraph_style, &font_collection);
+
+  txt::TextStyle text_style;
+  text_style.font_family = "Roboto";
+  text_style.font_size = 31;
+  text_style.letter_spacing = 0;
+  text_style.word_spacing = 0;
+  text_style.color = SK_ColorBLACK;
+  text_style.height = 1;
+  builder.PushStyle(text_style);
+  builder.AddText(u16_text);
+
+  builder.Pop();
+
+  // First Layout.
+  auto paragraph = builder.Build();
+  paragraph->Layout(300);
+
+  paragraph->Paint(GetCanvas(), 0, 0);
+
+  ASSERT_TRUE(Snapshot());
+  ASSERT_EQ(paragraph->text_.size(), std::string{text}.length());
+  for (size_t i = 0; i < u16_text.length(); i++) {
+    ASSERT_EQ(paragraph->text_[i], u16_text[i]);
+  }
+  ASSERT_EQ(paragraph->runs_.runs_.size(), 1ull);
+  ASSERT_EQ(paragraph->runs_.styles_.size(), 1ull);
+  ASSERT_TRUE(paragraph->runs_.styles_[0].equals(text_style));
+  ASSERT_EQ(paragraph->records_[0].style().color, text_style.color);
+  ASSERT_EQ(paragraph->GetLineCount(), 12);
+
+  // Second Layout.
+  SetUp();
+  paragraph->Layout(600);
+  paragraph->Paint(GetCanvas(), 0, 0);
+
+  ASSERT_TRUE(Snapshot());
+  ASSERT_EQ(paragraph->text_.size(), std::string{text}.length());
+  for (size_t i = 0; i < u16_text.length(); i++) {
+    ASSERT_EQ(paragraph->text_[i], u16_text[i]);
+  }
+  ASSERT_EQ(paragraph->runs_.runs_.size(), 1ull);
+  ASSERT_EQ(paragraph->runs_.styles_.size(), 1ull);
+  ASSERT_TRUE(paragraph->runs_.styles_[0].equals(text_style));
+  ASSERT_EQ(paragraph->records_[0].style().color, text_style.color);
+  ASSERT_EQ(paragraph->GetLineCount(), 6);
+  ASSERT_TRUE(Snapshot());
+}
+
 }  // namespace txt