tesseract/unittest/pango_font_info_test.cc

#include "tesseract/training/pango_font_info.h"

#include <stdio.h>
#include <string.h>

#include "pango/pango.h"
#include "tesseract/training/commandlineflags.h"
#include "tesseract/training/fileio.h"

DECLARE_STRING_PARAM_FLAG(fonts_dir);
DECLARE_STRING_PARAM_FLAG(fontconfig_tmpdir);
DECLARE_BOOL_PARAM_FLAG(use_only_legacy_fonts);

namespace {

using tesseract::File;
using tesseract::FontUtils;
using tesseract::PangoFontInfo;

// Fonts in testdata directory
const char* kExpectedFontNames[] = {"Arab",
                                    "Arial Bold Italic",
                                    "DejaVu Sans Ultra-Light",
                                    "Lohit Hindi",
#if PANGO_VERSION <= 12005
                                    "Times New Roman",
#else
                                    "Times New Roman,",  // Pango v1.36.2
                                                         // requires a trailing
                                                         // ','
#endif
                                    "UnBatang",
                                    "Verdana"};

// Sample text used in tests.
const char kArabicText[] = "والفكر والصراع 1234,\nوالفكر والصراع";
const char kEngText[] = "the quick brown fox jumps over the lazy dog";
const char kHinText[] = "पिताने विवाह की | हो गई उद्विग्न वह सोचा";
const char kKorText[] = "이는 것으로";
// Hindi words containing illegal vowel sequences.
const char* kBadlyFormedHinWords[] = {
#if PANGO_VERSION <= 12005
    "उपयोक्ताो", "नहीें", "कहीअे", "पत्रिाका", "छह्णाीस",
#endif
    // Pango v1.36.2 will render the above words even though they are invalid.
    "प्रंात", nullptr};

class PangoFontInfoTest : public ::testing::Test {
 protected:
  // Creates a fake fonts.conf file that points to the testdata fonts for
  // fontconfig to initialize with.
  static void SetUpTestCase() {
    FLAGS_fonts_dir = File::JoinPath(FLAGS_test_srcdir, "testdata");
    FLAGS_fontconfig_tmpdir = FLAGS_test_tmpdir;
    FLAGS_use_only_legacy_fonts = false;
  }

  PangoFontInfo font_info_;
};

TEST_F(PangoFontInfoTest, TestNonDefaultConstructor) {
  PangoFontInfo font("Arial Bold Italic 12");
  EXPECT_EQ(12, font.font_size());
  EXPECT_EQ("Arial", font.family_name());
}

TEST_F(PangoFontInfoTest, DoesParseFontDescriptionName) {
  EXPECT_TRUE(font_info_.ParseFontDescriptionName("Arial Bold Italic 12"));
  EXPECT_EQ(12, font_info_.font_size());
  EXPECT_EQ("Arial", font_info_.family_name());

  EXPECT_TRUE(font_info_.ParseFontDescriptionName("Verdana 10"));
  EXPECT_EQ(10, font_info_.font_size());
  EXPECT_EQ("Verdana", font_info_.family_name());

  EXPECT_TRUE(font_info_.ParseFontDescriptionName("DejaVu Sans Ultra-Light"));
  EXPECT_EQ("DejaVu Sans", font_info_.family_name());
}

TEST_F(PangoFontInfoTest, DoesParseMissingFonts) {
  // Font family one of whose faces exists but this one doesn't.
  EXPECT_TRUE(font_info_.ParseFontDescriptionName("Arial Italic 12"));
  EXPECT_EQ(12, font_info_.font_size());
  EXPECT_EQ("Arial", font_info_.family_name());

  // Font family that doesn't exist in testdata. It will still parse the
  // description name. But without the file, it will not be able to populate
  // some font family details, like is_monospace().
  EXPECT_TRUE(font_info_.ParseFontDescriptionName("Georgia 10"));
  EXPECT_EQ(10, font_info_.font_size());
  EXPECT_EQ("Georgia", font_info_.family_name());
}

TEST_F(PangoFontInfoTest, DoesGetSpacingProperties) {
  EXPECT_TRUE(font_info_.ParseFontDescriptionName("Arial Italic 12"));
  int x_bearing, x_advance;
  EXPECT_TRUE(font_info_.GetSpacingProperties("A", &x_bearing, &x_advance));
  EXPECT_GT(x_advance, 0);
  EXPECT_TRUE(font_info_.GetSpacingProperties("a", &x_bearing, &x_advance));
  EXPECT_GT(x_advance, 0);
}

TEST_F(PangoFontInfoTest, CanRenderString) {
  font_info_.ParseFontDescriptionName("Verdana 12");
  EXPECT_TRUE(font_info_.CanRenderString(kEngText, strlen(kEngText)));

  font_info_.ParseFontDescriptionName("UnBatang 12");
  EXPECT_TRUE(font_info_.CanRenderString(kKorText, strlen(kKorText)));

  font_info_.ParseFontDescriptionName("Lohit Hindi 12");
  EXPECT_TRUE(font_info_.CanRenderString(kHinText, strlen(kHinText)));
}

TEST_F(PangoFontInfoTest, CanRenderLigature) {
  font_info_.ParseFontDescriptionName("Arab 12");
  const char kArabicLigature[] = "لا";
  EXPECT_TRUE(
      font_info_.CanRenderString(kArabicLigature, strlen(kArabicLigature)));

  printf("Next word\n");
  EXPECT_TRUE(font_info_.CanRenderString(kArabicText, strlen(kArabicText)));
}

TEST_F(PangoFontInfoTest, CannotRenderUncoveredString) {
  font_info_.ParseFontDescriptionName("Verdana 12");
  EXPECT_FALSE(font_info_.CanRenderString(kKorText, strlen(kKorText)));
}

TEST_F(PangoFontInfoTest, CannotRenderInvalidString) {
  font_info_.ParseFontDescriptionName("Lohit Hindi 12");
  for (int i = 0; kBadlyFormedHinWords[i] != nullptr; ++i) {
    EXPECT_FALSE(font_info_.CanRenderString(kBadlyFormedHinWords[i],
                                            strlen(kBadlyFormedHinWords[i])))
        << "Can render " << kBadlyFormedHinWords[i];
  }
}

TEST_F(PangoFontInfoTest, CanDropUncoveredChars) {
  font_info_.ParseFontDescriptionName("Verdana 12");
  // Verdana cannot render the "ff" ligature
  string word = "office";
  EXPECT_EQ(1, font_info_.DropUncoveredChars(&word));
  EXPECT_EQ("oice", word);

  // Dont drop non-letter characters like word joiners.
  const char* kJoiners[] = {
      "\u2060",  // U+2060 (WJ)
      "\u200C",  // U+200C (ZWJ)
      "\u200D"   // U+200D (ZWNJ)
  };
  for (int i = 0; i < ARRAYSIZE(kJoiners); ++i) {
    word = kJoiners[i];
    EXPECT_EQ(0, font_info_.DropUncoveredChars(&word));
    EXPECT_STREQ(kJoiners[i], word.c_str());
  }
}

// ------------------------ FontUtils ------------------------------------

class FontUtilsTest : public ::testing::Test {
 protected:
  // Creates a fake fonts.conf file that points to the testdata fonts for
  // fontconfig to initialize with.
  static void SetUpTestCase() {
    FLAGS_fonts_dir = File::JoinPath(FLAGS_test_srcdir, "testdata");
    FLAGS_fontconfig_tmpdir = FLAGS_test_tmpdir;
  }

  void CountUnicodeChars(const char* utf8_text,
                         std::unordered_map<char32, inT64>* ch_map) {
    ch_map->clear();
    UnicodeText ut;
    ut.PointToUTF8(utf8_text, strlen(utf8_text));
    for (UnicodeText::const_iterator it = ut.begin(); it != ut.end(); ++it) {
      if (UnicodeProps::IsWhitespace(*it)) continue;
      ++(*ch_map)[*it];
    }
  }
};

TEST_F(FontUtilsTest, DoesFindAvailableFonts) {
  EXPECT_TRUE(FontUtils::IsAvailableFont("Arial Bold Italic"));
  EXPECT_TRUE(FontUtils::IsAvailableFont("Verdana"));
  EXPECT_TRUE(FontUtils::IsAvailableFont("DejaVu Sans Ultra-Light"));

  // Test that we can support font name convention for Pango v1.30.2 even when
  // we are running an older version.
  EXPECT_TRUE(FontUtils::IsAvailableFont("Times New Roman,"));
}

TEST_F(FontUtilsTest, DoesDetectMissingFonts) {
  // Only bold italic face is available.
  EXPECT_FALSE(FontUtils::IsAvailableFont("Arial"));
  // Dont have a ttf for the Courier family.
  EXPECT_FALSE(FontUtils::IsAvailableFont("Courier"));
  // Pango "synthesizes" the italic font from the available Verdana Regular and
  // includes it in its list, but it is not really loadable.
  EXPECT_FALSE(FontUtils::IsAvailableFont("Verdana Italic"));
  // We have "Dejavu Sans Ultra-Light" but not its medium weight counterpart.
  EXPECT_FALSE(FontUtils::IsAvailableFont("DejaVu Sans"));
}

TEST_F(FontUtilsTest, DoesListAvailableFonts) {
  const std::vector<string>& fonts = FontUtils::ListAvailableFonts();
  EXPECT_THAT(fonts, ::testing::ElementsAreArray(kExpectedFontNames));
  for (int i = 0; i < fonts.size(); ++i) {
    PangoFontInfo font_info;
    EXPECT_TRUE(font_info.ParseFontDescriptionName(fonts[i]));
  }
}

TEST_F(FontUtilsTest, DoesFindBestFonts) {
  string fonts_list;
  std::unordered_map<char32, inT64> ch_map;
  CountUnicodeChars(kEngText, &ch_map);
  EXPECT_EQ(26, ch_map.size());  // 26 letters
  std::vector<std::pair<const char*, std::vector<bool> > > font_flags;
  string best_list = FontUtils::BestFonts(ch_map, &font_flags);
  EXPECT_TRUE(best_list.size());
  // All fonts except Lohit Hindi should render English text.
  EXPECT_EQ(ARRAYSIZE(kExpectedFontNames) - 1, font_flags.size());

  CountUnicodeChars(kKorText, &ch_map);
  best_list = FontUtils::BestFonts(ch_map, &font_flags);
  EXPECT_TRUE(best_list.size());
  // Only UnBatang font family is able to render korean.
  EXPECT_EQ(1, font_flags.size());
  EXPECT_STREQ("UnBatang", font_flags[0].first);
}

TEST_F(FontUtilsTest, DoesSelectFont) {
  const char* kLangText[] = {kArabicText, kEngText, kHinText, kKorText, nullptr};
  const char* kLangNames[] = {"Arabic", "English", "Hindi", "Korean", nullptr};
  for (int i = 0; kLangText[i] != nullptr; ++i) {
    SCOPED_TRACE(kLangNames[i]);
    std::vector<string> graphemes;
    string selected_font;
    EXPECT_TRUE(FontUtils::SelectFont(kLangText[i], strlen(kLangText[i]),
                                      &selected_font, &graphemes));
    EXPECT_TRUE(selected_font.size());
    EXPECT_TRUE(graphemes.size());
  }
}

TEST_F(FontUtilsTest, DoesFailToSelectFont) {
  const char kMixedScriptText[] = "पिताने विवाह की | والفكر والصراع";
  std::vector<string> graphemes;
  string selected_font;
  EXPECT_FALSE(FontUtils::SelectFont(kMixedScriptText, strlen(kMixedScriptText),
                                     &selected_font, &graphemes));
}

TEST_F(FontUtilsTest, GetAllRenderableCharacters) {
  const int32 kHindiChar = 0x0905;
  const int32 kArabicChar = 0x0623;
  const int32 kMongolianChar = 0x180E;  // Mongolian vowel separator
  const int32 kOghamChar = 0x1680;      // Ogham space mark
  std::vector<bool> unicode_mask;
  FontUtils::GetAllRenderableCharacters(&unicode_mask);
  EXPECT_TRUE(unicode_mask['A']);
  EXPECT_TRUE(unicode_mask['1']);
  EXPECT_TRUE(unicode_mask[kHindiChar]);
  EXPECT_TRUE(unicode_mask[kArabicChar]);
  EXPECT_FALSE(unicode_mask[kMongolianChar]);  // no font for mongolian.
  EXPECT_FALSE(unicode_mask[kOghamChar]);      // no font for ogham.
  unicode_mask.clear();

  std::vector<string> selected_fonts;
  selected_fonts.push_back("Lohit Hindi");
  FontUtils::GetAllRenderableCharacters(selected_fonts, &unicode_mask);
  EXPECT_TRUE(unicode_mask['1']);
  EXPECT_TRUE(unicode_mask[kHindiChar]);
  EXPECT_FALSE(unicode_mask['A']);             // Lohit doesn't render English,
  EXPECT_FALSE(unicode_mask[kArabicChar]);     // or Arabic,
  EXPECT_FALSE(unicode_mask[kMongolianChar]);  // or Mongolian,
  EXPECT_FALSE(unicode_mask[kOghamChar]);      // or Ogham.

  // Check that none of the included fonts cover the Mongolian or Ogham space
  // characters.
  for (int f = 0; f < ARRAYSIZE(kExpectedFontNames); ++f) {
    SCOPED_TRACE(absl::StrCat("Testing ", kExpectedFontNames[f]));
    FontUtils::GetAllRenderableCharacters(kExpectedFontNames[f], &unicode_mask);
    EXPECT_FALSE(unicode_mask[kOghamChar]);
    EXPECT_FALSE(unicode_mask[kMongolianChar]);
  }
}
}  // namespace