BLO

Description

BLO performs specified logical operations on one or two bitmap segments stored in a database file.

Parameters

Name	Type	Length	Value range
InputBitmap1: Layer A  *	Bitmap port	1 - 1
InputBitmap2: Layer B	Bitmap port	0 - 1
Binary Function	String	2 - 1	AND, OR, XOR, SUB Default: AND
Unary Function	String	3 - 1	NOT Default: NOT
Layer Name	String	0 - 1
Layer Description	String	0 - 1
Output: Logical Results Layer: Output bitmap	Bitmap port	0 - 1

* Required parameter

Parameter descriptions

InputBitmap1: Layer A

Specifies the first input layer, consisting of bitmap 1 for the logical operation.

InputBitmap2: Layer B

Optionally specifies the second input layer, consisting of bitmap 2 for the logical operation.

Binary Function

Specifies the binary logical function to be performed.

Unary Function

Specifies the unary logical function to be performed.

Layer Name

Bitmap segment names are no longer supported, so the DBSN value is ignored. The DBSN parameter still remains to provide compatability for legacy applications.

Layer Description

Describes (in up to 64 characters) the contents or origins of the output bitmap.

Output: Logical Results Layer: Output bitmap

Optionally specifies the output bitmap segment to receive the generated logical result.

If this parameter is explicitly specified, the bitmap segment is overwritten. If it is not specified, a new bitmap segment is created.

Details

BLO performs logical operations on two database bitmap segments, unless the logical "NOT" has been specified, in which case only one bitmap is allowed.

If the output bitmap is specified, BLO writes the results of the logical operation to the specified segment number provided it exists and is of bitmap type (101). This bitmap segment will be overwritten without warning.

If no output bitmap is specified, BLO creates a new bitmap segment. A segment name of up to 8 characters must be specified and an optional 64-character description may be specified.