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https://github.com/tesseract-ocr/tesseract.git
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234 lines
10 KiB
C++
234 lines
10 KiB
C++
// (C) Copyright 2017, Google Inc.
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "include_gunit.h"
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#include "normstrngs.h"
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#include "normstrngs_test.h"
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namespace tesseract {
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namespace {
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// Though the unicode example for Telugu in section 12.7:
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// http://www.unicode.org/versions/Unicode9.0.0/ch12.pdf
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// shows using ZWNJ to force an explicit virama, in practice a ZWNJ is used to
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// suppress a conjugate that would otherwise occur. If a consonant is followed
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// by a virama and then by a non-Indic character, OpenType will presume that
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// the user simply meant to suppress the inherent vowel of the consonant
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// and render it as the consonant with an explicit virama, the same as if
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// a ZWNJ had followed. Since this is confusing to an OCR engine, the
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// normalizer always puts a termninating ZWNJ on the end if not present,
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// and accepts the string as valid.
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TEST(ValidateIndicTest, AddsJoinerToTerminalVirama) {
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std::string str = "\u0c15\u0c4d"; // KA - virama
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std::string target_str = "\u0c15\u0c4d\u200c"; // KA - virama - ZWNJ
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ExpectGraphemeModeResults(str, UnicodeNormMode::kNFC, 3, 2, 1, target_str);
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// Same result if we started with the normalized string.
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ExpectGraphemeModeResults(target_str, UnicodeNormMode::kNFC, 3, 2, 1,
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target_str);
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}
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// Only one dependent vowel is allowed.
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TEST(ValidateIndicTest, OnlyOneDependentVowel) {
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std::string str = "\u0d15\u0d3e\u0d42"; // KA AA UU
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std::string dest;
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EXPECT_FALSE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(),
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&dest))
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<< PrintString32WithUnicodes(str);
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}
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// [c26][c4d][c01]
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// A consonant (DA) followed by the virama followed by a bindu
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// Syllable modifiers [c01][c02][c03] all modify the pronunciation of
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// the vowel in a syllable, as does the virama [c04]. You can only
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// have one of these on a syllable.
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//
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// References:
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// http://www.omniglot.com/writing/telugu.htm
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TEST(ValidateIndicTest, OnlyOneVowelModifier) {
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std::string str = "\u0c26\u0c4d\u0c01"; // DA virama candrabindu
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std::string result;
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(),
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&result));
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// It made 1 grapheme of 4 chars, by terminating the explicit virama.
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EXPECT_EQ(std::string("\u0c26\u0c4d\u200c\u0c01"), result);
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str = "\u0995\u0983\u0981"; // KA visarga candrabindu
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EXPECT_FALSE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(),
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&result));
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// Exception: Malayalam allows multiple anusvara.
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str = "\u0d15\u0d02\u0d02"; // KA Anusvara Anusvara
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(),
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&result));
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EXPECT_EQ(str, result);
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}
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// [c28][c02][c3f]
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// A consonant (NA) followed by the Anusvara/sunna and another matra (I).
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// The anusvara [c02] is a pronunciation directive
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// for a whole syllable and only appears at the end of the syllable
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// References:
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// + Unicode v9, 12.1 "Modifier Mark Rules R10,"
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// and the Microsoft page
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// http://www.microsoft.com/typography/otfntdev/teluguot/shaping.aspx
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TEST(ValidateIndicTest, VowelModifierMustBeLast) {
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std::string str = "\u0c28\u0c02\u0c3f"; // NA Sunna I
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std::string dest;
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EXPECT_FALSE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(),
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&dest))
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<< PrintString32WithUnicodes(str);
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// Swap c02/c3f and all is ok.
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str = "\u0c28\u0c3f\u0c02"; // NA I Sunna
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(), &dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_EQ(dest, str);
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}
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// [c05][c47]
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// A Vowel (A) followed by a combining vowel/matra (EE).
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// In Telugu, matras are only put on consonants, not independent
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// vowels.
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// References:
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// + Unicode v9, 12.1:
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// Principles of the Devanagari Script: Dependent Vowel Signs (Matras).
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// + http://varamozhi.sourceforge.net/iscii91.pdf
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TEST(ValidateIndicTest, MatrasFollowConsonantsNotVowels) {
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std::string str = "\u0c05\u0c47"; // A EE
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std::string dest;
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EXPECT_FALSE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(),
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&dest))
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<< PrintString32WithUnicodes(str);
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str = "\u0c1e\u0c3e"; // NYA AA
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(), &dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_EQ(dest, str);
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}
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// Sub-graphemes are allowed if GraphemeNorm is turned off.
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TEST(ValidateIndicTest, SubGraphemes) {
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std::string str = "\u0d3e"; // AA
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std::string dest;
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EXPECT_FALSE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(),
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&dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNone, str.c_str(), &dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_EQ(dest, str);
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}
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TEST(ValidateIndicTest, Nukta) {
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std::string str = "\u0c95\u0cbc\u0ccd\u0cb9"; // KA Nukta Virama HA
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std::vector<std::string> glyphs;
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EXPECT_TRUE(NormalizeCleanAndSegmentUTF8(
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UnicodeNormMode::kNFC, OCRNorm::kNone, GraphemeNormMode::kGlyphSplit,
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true, str.c_str(), &glyphs));
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EXPECT_EQ(glyphs.size(), 3);
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EXPECT_EQ(glyphs[2], std::string("\u0ccd\u0cb9"));
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// Swapped Nukta and Virama are not allowed, but NFC normalization fixes it.
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std::string str2 = "\u0c95\u0ccd\u0cbc\u0cb9"; // KA Virama Nukta HA
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ExpectGraphemeModeResults(str2, UnicodeNormMode::kNFC, 4, 3, 1, str);
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}
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// Sinhala has some of its own specific rules. See www.macciato.com/sinhala
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TEST(ValidateIndicTest, SinhalaRakaransaya) {
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std::string str = "\u0d9a\u0dca\u200d\u0dbb"; // KA Virama ZWJ Rayanna
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std::string dest;
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(), &dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_EQ(dest, str);
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std::vector<std::string> glyphs;
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EXPECT_TRUE(NormalizeCleanAndSegmentUTF8(
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UnicodeNormMode::kNFC, OCRNorm::kNone, GraphemeNormMode::kGlyphSplit,
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true, str.c_str(), &glyphs));
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EXPECT_EQ(glyphs.size(), 2);
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EXPECT_EQ(glyphs[1], std::string("\u0dca\u200d\u0dbb"));
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// Can be followed by a dependent vowel.
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str += "\u0dd9"; // E
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(), &dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_EQ(dest, str);
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}
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TEST(ValidateIndicTest, SinhalaYansaya) {
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std::string str = "\u0d9a\u0dca\u200d\u0dba"; // KA Virama ZWJ Yayanna
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std::string dest;
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(), &dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_EQ(dest, str);
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// Can be followed by a dependent vowel.
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str += "\u0ddd"; // OO
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EXPECT_TRUE(NormalizeUTF8String(UnicodeNormMode::kNFC, OCRNorm::kNone,
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GraphemeNorm::kNormalize, str.c_str(), &dest))
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<< PrintString32WithUnicodes(str);
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EXPECT_EQ(dest, str);
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std::vector<std::string> glyphs;
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EXPECT_TRUE(NormalizeCleanAndSegmentUTF8(
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UnicodeNormMode::kNFC, OCRNorm::kNone, GraphemeNormMode::kGlyphSplit,
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true, str.c_str(), &glyphs));
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EXPECT_EQ(glyphs.size(), 3);
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EXPECT_EQ(glyphs[1], std::string("\u0dca\u200d\u0dba"));
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}
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TEST(ValidateIndicTest, SinhalaRepaya) {
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std::string str = "\u0d9a\u0dbb\u0dca\u200d\u0db8"; // KA Rayanna Virama ZWJ MA
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std::vector<std::string> glyphs;
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EXPECT_TRUE(NormalizeCleanAndSegmentUTF8(
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UnicodeNormMode::kNFC, OCRNorm::kNone, GraphemeNormMode::kCombined, true,
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str.c_str(), &glyphs));
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EXPECT_EQ(glyphs.size(), 2);
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EXPECT_EQ(glyphs[1], std::string("\u0dbb\u0dca\u200d\u0db8"));
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EXPECT_TRUE(NormalizeCleanAndSegmentUTF8(
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UnicodeNormMode::kNFC, OCRNorm::kNone, GraphemeNormMode::kGlyphSplit,
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true, str.c_str(), &glyphs));
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EXPECT_EQ(glyphs.size(), 3);
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EXPECT_EQ(glyphs[1], std::string("\u0dbb\u0dca\u200d"));
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}
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TEST(ValidateIndicTest, SinhalaSpecials) {
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// Sinhala has some exceptions from the usual rules.
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std::string str = "\u0dc0\u0d9c\u0dca\u200d\u0dbb\u0dca\u200d\u0dbb\u0dca\u200d";
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std::vector<std::string> glyphs;
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EXPECT_TRUE(NormalizeCleanAndSegmentUTF8(
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UnicodeNormMode::kNFC, OCRNorm::kNone, GraphemeNormMode::kGlyphSplit,
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true, str.c_str(), &glyphs));
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EXPECT_EQ(glyphs.size(), 5) << PrintStringVectorWithUnicodes(glyphs);
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EXPECT_EQ(glyphs[0], std::string("\u0dc0"));
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EXPECT_EQ(glyphs[1], std::string("\u0d9c"));
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EXPECT_EQ(glyphs[2], std::string("\u0dca\u200d\u0dbb"));
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EXPECT_EQ(glyphs[3], std::string("\u0dca\u200d"));
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EXPECT_EQ(glyphs[4], std::string("\u0dbb\u0dca\u200d"));
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str = "\u0dc3\u0dbb\u0dca\u200d\u0dbb\u0dca\u200d\u0dcf";
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EXPECT_TRUE(NormalizeCleanAndSegmentUTF8(
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UnicodeNormMode::kNFC, OCRNorm::kNone, GraphemeNormMode::kGlyphSplit,
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true, str.c_str(), &glyphs));
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EXPECT_EQ(glyphs.size(), 4) << PrintStringVectorWithUnicodes(glyphs);
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EXPECT_EQ(glyphs[0], std::string("\u0dc3"));
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EXPECT_EQ(glyphs[1], std::string("\u0dbb\u0dca\u200d"));
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EXPECT_EQ(glyphs[2], std::string("\u0dbb\u0dca\u200d"));
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EXPECT_EQ(glyphs[3], std::string("\u0dcf"));
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}
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} // namespace
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} // namespace tesseract
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