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The function RestrictSearchArea allows you to specify the search area as a rectangle, an array of rectangles, or a region.

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When to use RestrictSearchArea

On different pages of the document the sought field is often located differently relative to its name. For example, on some pages the field can be to the right of the name, on others it can be under the name. In such cases it is advisable to specify the search area as an array of rectangles. For more information about using the RestrictSearchArea function in such cases, see Search for elements with Nearest and FuzzyQuality. It may also be advisable to use the RestrictSearchArea function instead of duplicating search constraints that are identical for several elements. Use this function to describe the search area of the date field or any other field when, for some reason (for example, low image quality or layout peculiarities), the use of an element of one type is not enough.

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The SearchOfDate.fsp project with duplicated constraints

The RestrictSearchArea function can also be used to search for a date field. As a rule, search for date fields using at least two types of elements: Date and Character String. However, if the image quality is very low, these two elements may not be enough. For more information on how to organize a search for date fields, see Date search after high or low-quality recognition. To see this function at work, run the sample project SearchOfDate.fsp (folder %public%\ABBYY\FlexiCapture\12.0\Samples\FLS\Tips and Tricks\RestrictSearchArea). This project is a copy of the project of the same name from the Date\FCS project folder. The search constraints for all the elements in it (DateField, DateAsString, and DateAsObjectCollection) were identical, as shown in the following figure.
Screenshot of the Relations tab in the search element properties in ABBYY FlexiLayout Studio, showing the identical search constraints originally specified for the DateField, DateAsString, and DateAsObjectCollection elements in the SearchOfDate.fsp project.

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Replace duplicated constraints with RestrictSearchArea

In the current project, however, instead of duplicating the search constraints in the Relations tab for the DateAsString and DateAsObjectCollection elements, the RestrictSearchArea function is used, with the following code in the Advanced pre-search relations field on the Advanced tab:
This code means that searching for the date field as a string or as an object collection will be attempted only if FlexiLayout Studio fails to detect it by means of the Date element. Both elements will then be looked for in the same area where the DateField element was not detected. This happens because the DateField.Rect method returns the rectangle enclosing the hypothesis of the DateField element. Since the hypothesis has not been found, the enclosing rectangle will coincide with the search area. Therefore, the search area specified for the DateAsString and DateAsObjectCollection elements coincides with the rectangle enclosing the search area of the undetected DateField element.