In version 3.2, several optional features are added to Barcode ActiveX:

Data Matrix defines 30 different sizes. Most sizes are square, and a couple of them are rectangle. Regardless the final shape, the “real estate” unit, called module, is always square.

The size id, number of row and columns as well as the data capacity are listed in the table below.

In Barcode ActiveX you use DataMatrixTargetSizeID property to set the size you desire. If the property is set to 0, Barcode ActiveX picks up the size that fits the data encoded.

Previous to version 3.2, when DataMatrixTargetSizeID is too small to encode the whole data, Barcode ActiveX automatically increases the overall size. This behavior has changed in version 3.2. Now the progrom reports an error instead.

If DataMatrixTargetSizeID is more than holding the data, extra padding characters are added to the barcode. It is sometimes desirable if you want to have all the symbols created have the same size at the same time the data encoded vary from symbol to symbol.

Internally Barcode ActiveX uses an optimized algorithm to produce the smallest symbol as possible. Usually the size is small enough. It is possible to save 1 or 2 code words when there are no pads between the data code words and the security code words. When DataMatrixTargetSizeID is set to 0, Barcode ActiveX does not attempt to perform such an optimization. You have to ask Barcode ActiveX to perform such an optimization by setting the DataMatrixTargetSizeID to the size you desire to achieve.

Consider a data matrix symbol encoded with message ~5ABCABCABCABCABCABCABCABCABCABC. When DataMarixTargetSizeID is 0, Barcode ActiveX calculates the size as 22X22 which encodes 30 data code words. The total number of data code words required are 23, just one more than the capacity of 1 20X20 symbol. In this case, if you specify the property to 20X20, Barcode ActiveX will try to take a look that it can optimize the last symbol character. Since such optimization is allowed, Barcode ActiveX creates a 20X20 barcode instead of reporting an error.

The two barcodes below encode the same message ~5ABCABCABCABCABCABCABCABCABCABC. The left one is created under DataMarixTargetSizeID=0 (automatic). The right one is created under DataMatrixTargetSizeID=mbxDMTargetSize_20X20. Barcode ActiveX performs deep optimization when the target size is specified and creates a smaller symbol.

mbxDMTargetSizeAuto	mbxDMTargetSize_20X20

The deep optimization is used in scenarios when space is a primary concern. The data needs to meet certain conditions to make it possible.

The property DataMatrixModuleSize determines both the width and height of the smallest unit - a module. By default it is 20 mils. Same as all other length properties, the real value depends on Measurement.

Data Matrix is capable of encoding all characters in a single-byte character set, plus some symbol-specific characters. Depending on the programming environment you may need tilde codes to escape some characters. When creating data matrix barcodes, you can use the following tilde codes:

Data Matrix provides a way of abbreviating two industry specific header and trailer in one symbol character. This feature exists to reduce the overall symbol size. They must appear at the beginning of the input. You can use ~5 and ~6 to escape them respectively.

ECI was introduced to allow output data stream to have different interpretations different from the default character set (ISO8859-1). Since version 3.2, Barcode ActiveX has been capable of encoding ECI values.

An ECI can be any number between 0 and 999999. The tilde code ~7nnnnnn is used to enter the ECI value. The tilde code sequence can appear at any places of the input, but there must be exact 6 digits following ~7. For example to start an interpretation of 10, enter ~7000010.

The structural append feature allows up to 16 symbols in a structure. A capable reader can either buffer the contents of each symbol until all symbols are read.

To encode structural append, you must supply there items for each symbol:

The tilde code sequence is expressed in the following format:

~2[SI][FID][TS]

For example, tilde code sequence ~1[1][126][6] indicates that the current symbol belongs to a group with file identification number as 126, and there are 6 symbols in total in this group.

The ~2 tilde code sequence must appear at the end of the input. All three fields are required and must be enclosed with square brackets ([ and ]) and must follow the tilde code ~2.

File ID (FID)

The File ID is a number remaining the constant among all symbols in a group. It uniquely identifies the symbol group. The value for this field should be between 1 and 64516.

Sequence Indicator (SI)

Sequence Indicator is the 1-based index number of the current symbol. In a group with total 10 symbols, the first symbol has the SI of 1 and the last has the SI of 10.

Total Number of Symbols

The Total Number of symbols indicates how many symbols in the group.