Implement ParagraphStyle.line_height and add tests for line_height and baselines. (#6417)

third_party/txt/src/txt/paragraph.cc

@@ -729,14 +729,15 @@ void Paragraph::Layout(double width, bool force) {
     auto update_line_metrics = [&](const SkPaint::FontMetrics& metrics,
                                    const TextStyle& style) {
       double line_spacing =
-          (line_number == 0)
-              ? -metrics.fAscent * style.height
-              : (-metrics.fAscent + metrics.fLeading) * style.height;
+          (line_number == 0) ? -metrics.fAscent * style.height
+                             : (-metrics.fAscent + metrics.fLeading) *
+                                   style.height * paragraph_style_.line_height;
       if (line_spacing > max_line_spacing) {
         max_line_spacing = line_spacing;
         if (line_number == 0) {
           alphabetic_baseline_ = line_spacing;
-          // TODO(garyq): Properly implement ideographic_baseline_.
+          // TODO(garyq): Properly implement ideographic_baseline_ and update
+          // tests.
           ideographic_baseline_ =
               (metrics.fUnderlinePosition - metrics.fAscent) * style.height;
         }

third_party/txt/src/txt/paragraph.h

@@ -206,6 +206,7 @@ class Paragraph {
   FRIEND_TEST(ParagraphTest, RepeatLayoutParagraph);
   FRIEND_TEST(ParagraphTest, Ellipsize);
   FRIEND_TEST(ParagraphTest, UnderlineShiftParagraph);
+  FRIEND_TEST(ParagraphTest, LineHeightsParagraph);
 
   // Starting data to layout.
   std::vector<uint16_t> text_;

third_party/txt/src/txt/styled_runs.h

@@ -79,6 +79,7 @@ class StyledRuns {
   FRIEND_TEST(ParagraphTest, HyphenBreakParagraph);
   FRIEND_TEST(ParagraphTest, RepeatLayoutParagraph);
   FRIEND_TEST(ParagraphTest, Ellipsize);
+  FRIEND_TEST(ParagraphTest, LineHeightsParagraph);
 
   struct IndexedRun {
     size_t style_index = 0;

third_party/txt/tests/paragraph_unittests.cc

@@ -1731,4 +1731,155 @@ TEST_F(ParagraphTest, UnderlineShiftParagraph) {
   }
 }
 
+TEST_F(ParagraphTest, DISABLE_ON_WINDOWS(LineHeightsParagraph)) {
+  const char* text =
+      "This is a very long sentence to test if the text will properly wrap "
+      "around and go to the next line. Sometimes, short sentence. Longer "
+      "sentences are okay too because they are nessecary. Very short. "
+      "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod "
+      "tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim "
+      "veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea "
+      "commodo consequat. Duis aute irure dolor in reprehenderit in voluptate "
+      "velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint "
+      "occaecat cupidatat non proident, sunt in culpa qui officia deserunt "
+      "mollit anim id est laborum. "
+      "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod "
+      "tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim "
+      "veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea "
+      "commodo consequat. Duis aute irure dolor in reprehenderit in voluptate "
+      "velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint "
+      "occaecat cupidatat non proident, sunt in culpa qui officia deserunt "
+      "mollit anim id est laborum.";
+  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.max_lines = 14;
+  paragraph_style.text_align = TextAlign::left;
+  double line_height = 2.0;
+  paragraph_style.line_height = line_height;
+  txt::ParagraphBuilder builder(paragraph_style, GetTestFontCollection());
+
+  txt::TextStyle text_style;
+  text_style.font_family = "Roboto";
+  text_style.font_size = 26;
+  text_style.letter_spacing = 1;
+  text_style.word_spacing = 5;
+  text_style.color = SK_ColorBLACK;
+  text_style.height = 1;
+  text_style.decoration = TextDecoration::kUnderline;
+  text_style.decoration_color = SK_ColorBLACK;
+  builder.PushStyle(text_style);
+
+  builder.AddText(u16_text);
+
+  builder.Pop();
+
+  auto paragraph = builder.Build();
+  paragraph->Layout(GetTestCanvasWidth() - 100);
+
+  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(), 2ull);
+  ASSERT_TRUE(paragraph->runs_.styles_[1].equals(text_style));
+  ASSERT_EQ(paragraph->records_.size(), paragraph_style.max_lines);
+  double expected_y = 24;
+
+  ASSERT_TRUE(paragraph->records_[0].style().equals(text_style));
+  ASSERT_DOUBLE_EQ(paragraph->records_[0].offset().y(), expected_y);
+  expected_y += 27.5 * line_height;
+  ASSERT_DOUBLE_EQ(paragraph->records_[0].offset().x(), 0);
+
+  ASSERT_TRUE(paragraph->records_[1].style().equals(text_style));
+  ASSERT_DOUBLE_EQ(paragraph->records_[1].offset().y(), expected_y);
+  expected_y += 27.5 * line_height;
+  ASSERT_DOUBLE_EQ(paragraph->records_[1].offset().x(), 0);
+
+  ASSERT_TRUE(paragraph->records_[2].style().equals(text_style));
+  ASSERT_DOUBLE_EQ(paragraph->records_[2].offset().y(), expected_y);
+  expected_y += 27.5 * line_height;
+  ASSERT_DOUBLE_EQ(paragraph->records_[2].offset().x(), 0);
+
+  ASSERT_TRUE(paragraph->records_[3].style().equals(text_style));
+  ASSERT_DOUBLE_EQ(paragraph->records_[3].offset().y(), expected_y);
+  expected_y += 27.5 * 10 * line_height;
+  ASSERT_DOUBLE_EQ(paragraph->records_[3].offset().x(), 0);
+
+  ASSERT_TRUE(paragraph->records_[13].style().equals(text_style));
+  ASSERT_DOUBLE_EQ(paragraph->records_[13].offset().y(), expected_y);
+  ASSERT_DOUBLE_EQ(paragraph->records_[13].offset().x(), 0);
+
+  ASSERT_EQ(paragraph_style.text_align,
+            paragraph->GetParagraphStyle().text_align);
+
+  // Tests for GetGlyphPositionAtCoordinate()
+  ASSERT_EQ(paragraph->GetGlyphPositionAtCoordinate(0, 0).position, 0ull);
+  ASSERT_EQ(paragraph->GetGlyphPositionAtCoordinate(1, 1).position, 0ull);
+  ASSERT_EQ(paragraph->GetGlyphPositionAtCoordinate(1, 35).position, 68ull);
+  ASSERT_EQ(paragraph->GetGlyphPositionAtCoordinate(1, 70).position, 68ull);
+  ASSERT_EQ(paragraph->GetGlyphPositionAtCoordinate(2000, 35).position, 134ull);
+
+  ASSERT_TRUE(Snapshot());
+}
+
+TEST_F(ParagraphTest, BaselineParagraph) {
+  const char* text =
+      "左線読設Byg後碁給能上目秘使約。満毎冠行来昼本可必図将発確年。今属場育"
+      "図情闘陰野高備込制詩西校客。審対江置講今固残必託地集済決維駆年策。立得";
+  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.max_lines = 14;
+  paragraph_style.text_align = TextAlign::justify;
+  paragraph_style.line_height = 1.5;
+  txt::ParagraphBuilder builder(paragraph_style, GetTestFontCollection());
+
+  txt::TextStyle text_style;
+  text_style.color = SK_ColorBLACK;
+  text_style.font_size = 55;
+  text_style.letter_spacing = 2;
+  text_style.font_family = "Source Han Serif CN";
+  text_style.decoration_style = txt::TextDecorationStyle::kSolid;
+  text_style.decoration_color = SK_ColorBLACK;
+  builder.PushStyle(text_style);
+
+  builder.AddText(u16_text);
+
+  builder.Pop();
+
+  auto paragraph = builder.Build();
+  paragraph->Layout(GetTestCanvasWidth() - 100);
+
+  paragraph->Paint(GetCanvas(), 0, 0);
+
+  SkPaint paint;
+  paint.setStyle(SkPaint::kStroke_Style);
+  paint.setAntiAlias(true);
+  paint.setStrokeWidth(1);
+  paint.setColor(SK_ColorRED);
+  GetCanvas()->drawLine(0, paragraph->GetIdeographicBaseline(),
+                        paragraph->GetMaxWidth(),
+                        paragraph->GetIdeographicBaseline(), paint);
+
+  paint.setColor(SK_ColorGREEN);
+
+  GetCanvas()->drawLine(0, paragraph->GetAlphabeticBaseline(),
+                        paragraph->GetMaxWidth(),
+                        paragraph->GetAlphabeticBaseline(), paint);
+  ASSERT_DOUBLE_EQ(paragraph->GetIdeographicBaseline(), 70.180000305175781);
+  ASSERT_DOUBLE_EQ(paragraph->GetAlphabeticBaseline(), 63.305000305175781);
+
+  ASSERT_TRUE(Snapshot());
+}
+
 }  // namespace txt