Line Snap Options

Configures automatic snapping of a rectangular region to nearby lines detected in a document image.

Remarks

The Line Snap Options class provides settings to automatically adjust the edges of a rectangular region—such as a zone or field—so they align with lines found on a document page. This is useful for precisely capturing table cells, form fields, or other structured regions where alignment to printed lines is important.

Overview

• Snapping is performed by searching for horizontal and vertical lines near the region's edges.
• The 'Auto Snap Distance' property controls how far from each edge to search for a line.
• The 'Auto Snap Margin' property allows you to shrink the resulting region after snapping, to avoid overlapping the detected lines.
• If snapping is disabled or no lines are found within the specified distance, the original region is used.

How It Works

1. The snapping process begins with a rectangular region and a Document Instance containing layout information for the target page.
2. For each edge (left, top, right, bottom), the system checks the corresponding value in 'Auto Snap Distance':
   • If the value is nonzero, it searches for the nearest line within that distance using the page Layout Data.
   • If a line is found, the region's edge is moved to align with the detected line, plus any offset specified by 'Auto Snap Margin' and a small boundary adjustment.
   • If no line is found or the distance is zero, the edge remains unchanged.
3. After all applicable edges are processed, the region is checked for validity (ensuring left < right and top < bottom).
   • If the region is invalid after snapping, the original region is returned.
   • Otherwise, the adjusted region is used for further processing or extraction.

This approach ensures that extracted regions closely match the actual printed lines on the document, improving accuracy for structured data extraction.

Properties

Name	Type		Description
Auto Snap Distance	Logical Border	►	Specifies the maximum distance from each edge to search for a line when auto-snapping a region. ConverterLogical Border Converter Set the value for each edge (left, top, right, bottom) using a Logical Border. If the value is zero or empty for an edge, snapping is disabled for that edge. When set, lines detected within the specified distance will be used to adjust the region's edge, aligning it to the nearest line. Useful for ensuring that extracted regions precisely match the printed lines on a document.
Auto Snap Margin	Logical Border	►	Specifies the amount to shrink the region on each edge after snapping to a line. ConverterLogical Border Converter Set the value for each edge (left, top, right, bottom) using a Logical Border. After a successful snap, the region is reduced by the specified margin on each edge. Use this to avoid overlapping the detected lines, which can improve extraction accuracy and visual appearance. If not set, no margin is applied.

Derived Types

There are 1 implementations of Line Snap Options.

Result Snap Options

Defines settings for snapping a text extraction result to nearby lines and updating the extracted value.

See Also

Logical Border

Used By

Fixed RegionRelative RegionShape RegionText Region