ImageGear for C and C++ on Windows v19.2 - Updated
enumIGRecChrFilter
API Reference Guide > Recognition Component API Reference > Recognition Component Enumerations Reference > enumIGRecChrFilter

Recognition filters.

Values:

IG_REC_FILTER_DEFAULT Use this value to have the zone handled globally. Do not combine this with any other filters.
IG_REC_FILTER_DIGIT [Disjunct filter] Recognition of numerals only. E.g.: "3" (Digit Three).
IG_REC_FILTER_UPPERCASE [Disjunct filter] Recognition of uppercase letters only, including accented ones.E.g.: "A" (Capital A).
IG_REC_FILTER_LOWERCASE [Disjunct filter] Recognition of lowercase letters only, including accented ones. E.g.: "a" (Lowercase a).
IG_REC_FILTER_PUNCTUATION [Disjunct filter] Recognition of punctuation signs only. E.g.: "!" (Exclamation Mark).
IG_REC_FILTER_MISCELLANEOUS [Disjunct filter] Recognition of other miscellaneous characters only. E.g.: "+" (Plus sign).
IG_REC_FILTER_PLUS [Special, combinable filter] Enables the use of the FilterPlus characters specified by the IG_REC_filterplus_set function. The FilterPlus characters are added after any kind of filtering.
IG_REC_FILTER_USER_DICT [Special, combinable filter] Recognition of characters from the user dictionary section assigned to the zone.
IG_REC_FILTER_ALL [Pre-defined combined filter] Since all elements are enabled, there is no filtering.
IG_REC_FILTER_ALPHA [Pre-defined combined filter] Recognition of upper and lowercase letters only.
IG_REC_FILTER_NUMBERS [Pre-defined combined filter] Recognition of digits and the FilterPlus characters set by the IG_REC_filterplus_set function.
IG_REC_FILTER_SIZE Number of possible combinations of the disjunct filters.

Remarks:

This enum lists available Character Set filter elements. Language environment can be narrowed down by specifying Character Set filters. The name of each filter element denotes the category of characters it validates. A filter is built from one or more filter elements by combining (binary OR-ing) them. There are five disjunct elements, a special one and some pre-defined, combined ones. The filters can have an effect either at zone level (by specifying the zone's filter field) or globally, at page level (defined by the IG_REC_default_filter_set function). Use the value IG_REC_FILTER_ALL to set no filtering.

Characters in the document that are not part of the specified Character Set will either be rejected or will be recognized as a validated character with a similar shape. For instance, if you select English only and the document contains a letter "Capital A with acute", the recognized output will be the letter "Capital A".

The capabilities of the selected recognition module can also impose restrictions.

Not all recognition modules support all filter elements:

To add IG_REC_FILTER_PLUS characters to the Character Set defined by the language environment, the filter value should be: IG_REC_FILTER_FILTER_ALL | IG_REC_FILTER_FILTER_PLUS.

To add IG_REC_FILTER_PLUS characters to the filtered Character Set, place IG_REC_FILTER_PLUS along with the other required filters. For example, to enable only digits and IG_REC_FILTER_PLUS characters, use: IG_REC_FILTER_FILTER_DIGIT | IG_REC_FILTER_FILTER_PLUS.

To validate IG_REC_FILTER_PLUS characters only, IG_REC_FILTER_FILTER_PLUS must be the only filter element in the zone structure field. This even prevents language selection from validating letters in the current zone.