Merge pull request #526 from fnatzke/Issue455-Issue_extracting_unicode_from_CJK_file

Fix #455 extracting unicode from CJK file

src/UglyToad.PdfPig.Tests/Integration/Type0_CJK_FontTests.cs

@@ -0,0 +1,99 @@
+namespace UglyToad.PdfPig.Tests.Integration
+{
+    using System.IO;
+    using System.Linq;
+    using Content;
+    using Xunit;
+
+    public class Type0_CJK_FontTests
+    {
+        private static string GetFilename()
+        {
+            return IntegrationHelpers.GetDocumentPath("Type0_CJK_Font");
+        }
+
+        [Fact]
+        public void HasCorrectNumberOfPages()
+        {
+            var file = GetFilename();
+
+            using (var document = PdfDocument.Open(File.ReadAllBytes(file)))
+            {
+                Assert.Equal(95, document.NumberOfPages);
+            }
+        }
+ 
+
+        [Fact]
+        public void HasCorrectChineseCharacters()
+        {
+            using (var document = PdfDocument.Open(GetFilename()))
+            {
+                var page = document.GetPage(1);
+
+                var text = string.Join(string.Empty, page.Letters.Select(x => x.Value));
+
+                Assert.True(text?.Contains("中航动力控制股份有限公司"));
+                Assert.True(text?.Contains("年半年度报告"));
+                Assert.True(text?.Contains("中航动力控制股份有限公司董事会"));
+                Assert.True(text?.Contains("2010年8月17日"));
+
+                //charcode, cid, unicode, char,0xc1a6,0x09ef,\u529b,力
+                //charcode, cid, unicode, char,0xbfd8,0x0965,\u63a7,控
+                //charcode, cid, unicode, char,0xd6c6,0x11c5,\u5236,制
+                //charcode, cid, unicode, char,0xb9c9,0x0722,\u80a1,股
+                //charcode, cid, unicode, char,0xb7dd,0x067a,\u4efd,份
+                //charcode, cid, unicode, char,0xd3d0,0x10b5,\u6709,有
+                //charcode, cid, unicode, char,0xcfde,0x0f4b,\u9650,限
+                //charcode, cid, unicode, char,0xb9ab,0x0704,\u516c,公
+                //charcode, cid, unicode, char,0xcbbe,0x0db3,\u53f8,司
+                //charcode, cid, unicode, char,0xb6ad,0x05ec,\u8463,董
+                //charcode, cid, unicode, char,0xcac2,0x0d59,\u4e8b,事
+                //charcode, cid, unicode, char,0xbbe1,0x07f6,\u4f1a,会
+                //charcode, cid, unicode, char,0xc4ea,0x0b4d,\u5e74,年
+                //charcode, cid, unicode, char,0xd4c2,0x1105,\u6708,月
+                //charcode, cid, unicode, char,0xc8d5,0x0cb0,\u65e5,日
+
+
+                /*
+                 Font Dictionary of Page 1
+                 Name	References
+                TT2  	321
+                TT4  	322
+                TT6  	327
+                TT7  	329
+                TT9  	330
+                TT10 	322
+
+                Font Details
+                TT2 {[BaseFont, {/TimesNewRoman}]} {[Encoding, {/WinAnsiEncoding}]}
+                TT4 {[BaseFont, {/TimesNewRoman,Bold}]} {[Encoding, {/WinAnsiEncoding}]}
+                TT6 {[BaseFont, {/KaiTi_GB2312}]} {[Encoding, {/GBK-EUC-H}]}
+	                DescendndFont 	{[BaseFont, {/KaiTi_GB2312}]}
+			                {[Subtype, {/CIDFontType2}]}
+			                {[CIDSystemInfo, {<Registry, (Adobe)>, <Ordering, (GB1)>, <Supplement, 2>}]}
+	
+                TT7 {[BaseFont, {/KaiTi_GB2312+2}]} 
+	                {[Subtype, {/TrueType}]}
+	                {[Encoding, {/WinAnsiEncoding}]}
+	                {[BaseFont, {/KaiTi_GB2312+2}]}
+
+
+                TT9 {[BaseFont, {/SimHei}]} 
+	                {[Subtype, {/TrueType}]}
+	                {[Encoding, {/WinAnsiEncoding}]}
+
+                TT10 {[BaseFont, {/SimHei+2}]}
+	                {[Encoding, {/GBK-EUC-H}]}
+	                {[Subtype, {/Type0}]}
+	                DescendndFont	
+		                {[Subtype, {/CIDFontType2}]}
+		                {[CIDSystemInfo, {<Registry, (Adobe)>, <Ordering, (GB1)>, <Supplement, 2>}]}	
+		                {[BaseFont, {/SimHei+2}]}
+                 */
+            }
+        }
+
+         
+    }
+}

src/UglyToad.PdfPig/PdfFonts/Composite/Type0Font.cs

@@ -8,7 +8,7 @@
     using Geometry;
     using Tokens;
     using Util.JetBrains.Annotations;
-
+    using Debug = System.Diagnostics.Debug;
     /// <summary>
     /// Defines glyphs using a CIDFont
     /// </summary>
@@ -66,16 +66,37 @@
 
         public bool TryGetUnicode(int characterCode, out string value)
         {
-            value = null;
-
-            if (!ToUnicode.CanMapToUnicode)
+            value = null;
+
+            var HaveCMap = ToUnicode.CanMapToUnicode;
+            if (HaveCMap == false)
             {
-                if (ucs2CMap != null && ucs2CMap.TryConvertToUnicode(characterCode, out value))
-                {
-                    return value != null;
-                }
+                var HaveUnicode2CMap = (ucs2CMap is null == false); 
+                if (HaveUnicode2CMap)
+                {
+                    // Have both ucs2Map and CMap convert to unicode by
+                    // characterCode  ----by CMAP---> CID ---ucs2Map---> Unicode
+                    var CID = CMap.ConvertToCid(characterCode);
+                    if (CID == 0)
+                    {
+                        Debug.WriteLine($"Warning: No mapping from characterCode (0x{characterCode:X} to CID by ucs2Map.");
+                        return false; // No mapping from characterCode to CID.
+                    }
+                    // CID ---ucs2Map---> Unicode
+                    if (ucs2CMap.TryConvertToUnicode(CID, out value))
+                    {
+                        return value != null;
+                    }
 
-                return false;
+                }
+                if (HaveUnicode2CMap) // 2022-12-24 @fnatzke left as fall-back. Possible?
+                {
+                    // characterCode ---ucs2Map---> Unicode      (?) @fnatzke possible?
+                    if (ucs2CMap.TryConvertToUnicode(characterCode, out value))
+                    {
+                        return value != null;
+                    }
+                }
             }
 
             // According to PdfBox certain providers incorrectly using Identity CMaps as ToUnicode.