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OcrSpellCheckEngine Enumeration


OCR Spell Checker Type

public enum OcrSpellCheckEngine 
Public Enum OcrSpellCheckEngine 
typedef NS_ENUM(NSInteger, LTOcrSpellCheckEngine) 
public enum OcrSpellCheckEngine 
public enum class OcrSpellCheckEngine 

0None No spell checker (disables the spell check sub system)
1Native Native engine spell checker.
2OS The operating system spell checker.
3Hunspell Hunspell spell checker.


Refer to IOcrSpellCheckManager for more information about the types of spell check engines available and any restrictions.

Set IOcrSpellCheckManager.SpellCheckEngine to OcrSpellCheckEngine.None to disable the spell checking sub system. Only one spell check language can be enabled at a time using IOcrSpellCheckManager.SpellLanguage.

The OcrEngineType.OmniPage engine supports the OcrSpellCheckEngine.None only. This is the internal spell checker that ships with the LEADTOOLS OCR Module - OmniPage Engine runtimes. User words and dictionaries are not supported.

The OcrEngineType.LEAD engine supports all OcrSpellCheckEngine types. User words and dictionaries are supported and the engine automatically loads the dictionaries based on the language(s) currently enabled in IOcrLanguageManager. IOcrSpellCheckManager.SpellLanguage is not used and will have no effect.

The following information is only for the OcrEngineType.LEAD engine.

All LEADTOOLS OCR Module - LEAD Engine spell checker engines support adding user words to create custom dictionaries through IOcrSpellCheckManager.AddUserWords.

The OcrSpellCheckEngine.Native engine uses the internal LEADTOOLS cross-platform spell checker. The dictionary files ship with LEADTOOLS in the LEAD OCR runtime in the following format LEAD.[Language].dic where [Language] is the specific language (such as "en" for English or "de" for German). This engine has no extra dependencies, except for the dictionary files.

The OcrSpellCheckEngine.OS engine uses the Operating System-specific spell checker, if any. In the Windows environment, this is the .NET spell checker (requires .NET 3.0 or later to be installed on the machine) which supports only English, French, German and Spanish. In order to use this engine, Leadtools.SpellCheckers.OS.dll must exist in the Bin folder next to the Leadtools.Ocr.LEADEngine.dll.

The OcrSpellCheckEngine.Hunspell uses the popular Hunspell spell checker (using the standard .NET NHunspell wrapper). The LEADTOOLS setup does not contain the NHunspell binaries or any language dictionaries. Download the required assemblies from the NHunspell page as well as the dictionaries for the languages you are interested in. Visit the NHunspell home page at https://www.nuget.org/packages/NHunspell/ for more information.

Using Hunspell Engine with LEADTOOLS OCR Module - LEAD Engine

The following prerequisites must exist in order for you to use the Hunspell engine with LEADTOOLS OCR Module - LEAD Engine:

  • The Leadtools.SpellCheckers.Hunspell.dll assembly must be in the Bin folder next to Leadtools.Ocr.LEADEngine.dll.

  • NHunspell.dll: NHunspell .NET wrapper. Must be in the bin folder next to Leadtools.SpellCheckers.Hunspell.dll.

  • Hunspellx86.dll or Hunspellx64.dll: Hunspell native DLL. The correct version for your platform must exist in the LEADTOOLS OCR Module - LEAD Engine runtime folder. By default, the location is:


  • lang.aff and lang.dic dictionary files: Language dictionary files for the Hunspell engine. Visit https://wiki.openoffice.org/wiki/Dictionaries to download the files for the languages you are interested in. You can use the same name as the original dictionary file, for example, "en_US" for English US dictionary. The dictionary file must reside in the LEADTOOLS OCR Module - LEAD Engine runtime folder. By default, the location is:



For an example, refer to IOcrSpellCheckManager.


Target Platforms

See Also


Leadtools.Ocr Namespace

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Leadtools.Ocr Assembly