ClipHelper.EvaluateGraybox2 method

This method determines the presence of data on a region on the sheet by scanning each raster. It also computes a measure of the data relative to the specified graybox cutoff value. If this value equals or exceeds ClipHelper.GrayboxCutoff, the calculation is terminated and the value returned. The returned value ranges from 0 thru 15.

You can use this method to determine whether or not to clip a region of a form based on whether an evaluation region has data or not. The evaluation region is typically but not necessarily a subset of the region to be clipped.

Make sure that the evaluation region is not too close to the edges of the sheet to avoid problems due to skew.

The minimum size of the graybox is about 1.5mm square or 0.1" square. Refer to ScanTools Plus Help for exact metrics.

This method uses the current values of the following properties:

1. ClipHelper.ClipCoordinateSpace (qualifies ClipRegion)

You can use OMR or world coordinates, but not pixels. If using OMR coordinates, the form must have timing marks for the side of interest.

2. ClipHelper.UnitOfMeasure (qualifies ClipRegion)

This applies if you use world coordinates

3. ClipHelper.GrayboxCutoff

Valid

See ScanEventArgs and ScanningManager Events Valid Combinations.

IDL

HRESULT EvaluateGraybox2(

[in] ClipAttributes* ClipAttributes,  

[out, retval] long* ActualLevel);

Input Parameters

Return Values

See also