Change the symbologies' default properties

Motivation

Symbologies often have different properties, such as symbol count (length of the barcode) or inverted colors (printed white on black). To provide optimal performances, some properties/values are disabled by default in our SDK. You might need to scan a symbology whose properties are by default disabled. This article explains you how to enable the specific properties and which one are available per symbology.

How to set a specific property

You will be able to set the properties of a symbology using the methods of the SymbologySettings class (naming can vary slightly across platforms). For example, on Android, you can get the symbology settings of code 128 the following way:

SymbologySettings symSettings = settings.getSymbologySettings(Barcode.SYMBOLOGY_CODE128);
  • Checksums: Some symbologies have optional checksum. You can enforce it with the dedicated checksum method of the SymbologySettings class. On Android:
    symSettings.setChecksums(SymbologySettings.CHECKSUM_MOD_10);
  • Symbol Count Range: Some symbologies have a certain length range configured by default. You might know the length of a barcode by using the "Any Code" mode of our demo app (Apple/Play Store). You can set a new range using the dedicated symbol count method on the SymbologySettings class. On Android:
    short[] activeSymbolCounts = new short[] {
    7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
    };
    symSettings.setActiveSymbolCounts(activeSymbolCounts);
  • Color-Inverted Codes: Some symbologies can be printed white on black (default is black on white). You can set it using the dedicated inverted color method on the SymbologySettings class. On Android:
    symSettings.setColorInvertedEnabled(true);
  • Extension: Some symbologies have other possible extensions/properties (see the section below: "Symbology Extension Descriptions"). You can enforce these properties through a generic method on the SymbologySettings class. On Android:
    symSettings.setExtensionEnabled(relaxed_sharp_quiet_zone_check, false);

1D Symbologies Properties

  • All symbologies and all extensions are disabled by default when using the low-level API.
  • Color-inverted (bright bars on dark background) decoding for symbologies that support it is disabled and must be explicitly enabled.
  • Optional checksum digits (e.g. for interleaved 2 of 5 codes, or MSI-Plessey codes) are always returned as part of the data.
Symbology Mandatory Checksums Supported Optional
Checksums
Default Optional
Checksum
Default Symbol Count Range Supported Symbol Count Range Color-Inverted
Codes
Extensions Generator Support
EAN-13 mod10 12 12 yes relaxed_sharp_quiet_zone_check, strict yes
EAN-8 mod10 8 8 yes relaxed_sharp_quiet_zone_check, strict no
UPC-A mod10 12 12 yes relaxed_sharp_quiet_zone_check, remove_leading_zero, strict yes
UPC-E mod10 6 6 yes return_as_upca, remove_leading_upca_zero, strict no
Two-Digit Add-on mod10 2 2 yes strict no
Five-Digit Add-on mod10 5 5 yes strict no
MSI Plessey none mod10, mod11, mod1010, mod1110 mod10 6-32 3-32 no strict no
Code 128 mod103 6-40 (includes 1 checksum and 2 guard symbols) 4-50 yes strip_leading_fnc11, strict yes
Code 11 none mod11 mod11 7-20 (includes 0-2 checksum digits) 3-32 no strict no
Code 25 none mod10 7-20 3-32 no strict no
IATA 2 of 5 none mod1010 7-20 3-32 no strict no
Matrix 2 of 5 none mod10 7-20 3-32 no strict no
Code 32 mod10 8 (plus one check digit) 8 no strict no
Code 39 none mod43 6-40 (includes 2 guard symbols) 3-50 yes full_ascii, relaxed_sharp_quiet_zone_check, strict yes
Code 93 mod47 6-40 (includes 2 checksums and 2 guard symbols) 5-60 no full_ascii2, strict no
Codabar none mod16, mod11 7-20 (includes 2 guard symbols) 3-34 no strict no
GS1 DataBar 14 mod10 2 (encoding 14 digits) 2 no strict no
GS1 DataBar Expanded mod211 1-11 (encoding 1-74 characters) 1-11 no strict no
GS1 DataBar Limited mod89 1 (encoding 14 digits) 1 no relaxed_sharp_quiet_zone_check, strict no
Interleaved-Two-of-Five (ITF) none mod10 6-40 4-50 no strict yes
RM4SCC mod36 7-24 4-50 no no
KIX none 7-24 7-24 no no
LAPA none 16 16 no no
USPS Intelligent Mail none 65 65 no no
UPU 4-State none 19 or 25 19 or 25 no fluorescent_orange_ink no
Australian Post 4-State none 10-41 (10 digits, 0-31 customer info characters)10-41 no one of force_table_c, force_table_n, decode_bar_states no
French Post none - - no fluorescent_orange_ink3 no

1: Enabled by default.
2: Always enabled and can't be disabled.
3: Required for scanning.

2D Symbologies Properties

  • All symbologies and all extensions are disabled by default when using the low-level API.
  • Color-inverted decoding for symbologies that support it is disabled and must be explicitly enabled.
Symbology Color-Inverted
Codes
Extensions Generator Support
ArUco yes no
Aztec Code yes no
Data Matrix yes strip_leading_fnc11, direct_part_marking_mode yes
DotCode yes no
MaxiCode no no
MicroPDF417 no no
PDF417 no no
QR Code yes strict yes
Micro QR Code yes no

1: Enabled by default.

Symbology Extension Descriptions

  • full_ascii: Interprets the Code39 code data using two symbols per output character to encode all ASCII characters.
  • relaxed_sharp_quiet_zone_check: Enables scanning codes that have quiet zones (white area before and after the code) that are significantly smaller than allowed by the symbology specification. Use this extension if you are having difficulties to scan codes due to quiet zone violations. However, enabling it may come at the cost of more false positives under certain circumstances.
  • return_as_upca: Transforms the UPCE result into its UPCA representation.
  • remove_leading_zero: Removes the leading zero digit from the result.
  • remove_leading_upca_zero: Removes the leading zero digit from the result if the UPCA representation extension 'return_as_upca' is enabled.
  • strip_leading_fnc1: Removes the leading FNC1 character that indicates a GS1 code. To determine whether a certain code is a GS1 code, use sc_barcode_is_gs1_data_carrier.
  • direct_part_marking_mode: Use this mode to improve scan performance when reading direct part marked (DPM) Data Matrix codes. Enabling this extension comes at the cost of increased frame processing times. It is recommended to restrict the scanning area to a smaller part of the image for best performance.
  • strict: Enforce strict standard adherence to eliminate false positives in blurry, irregular or damaged barcodes at the cost of reduced scan performance.
  • fluorescent_orange_ink: Enables the scanning of low contrast fluorescent orange codes. Enabling this option can have a negative impact on the scan performance of other symbologies.
  • For Australian Post 4-State, customer information is decoded by default with Table N, and Table C is used as a fallback. force_table_c and force_table_n respectively enforce decoding with either C or N tables, and the symbology extension decode_bar_states will return the error-corrected customer information bars as a string of the bar states, A for ascending, D for descending, T for tracker and F for full.

The length of data encoded in variable-length symbologies such as Code 128, Codabar, Code 39 etc. is measured as the number of symbols. Depending on the symbology, the symbol count includes the start and end symbol, and/or checksum characters. The following list shows how to calculate the number of symbols for each variable-length symbology. These counts can be used as the input to sc_symbology_settings_set_active_symbol_counts.

  • Interleaved-Two-of-Five: The number of symbols corresponds to the number of digits in the code. Note that the number of digits must be even. Example: the code "1234567890123" has a symbol count of 14. For the active symbol count calculation, optional checksum digits are treated like normal data symbols.
  • Codabar: The number of symbols corresponds to the number of digits in the code, plus the start and end symbols. Example: the code "A2334253D" has a symbol count of 7 + 2 = 9.
  • Code 11: The number of symbols corresponds to the number of digits in the code, plus one or two checksum symbols. For less than ten digits in the code, one checksum symbol is added. Two checksum symbols are added for ten or more digits in the code. Example: the code "912-34956" ("912-349566") has a symbol count of 9 + 1 = 10. The code "912-3495-6" ("912-3495-638") has a symbol count of 10 + 2 = 12.
  • Code 128: The number of symbols depends on the encoding used (A, B or C). All encodings require a start, an end and a checksum symbol. The ASCII encoding modes (A and B) store each character in one symbol. Example: the code "ABC123" in mode A has a symbol count of 6 + 2 + 1 = 9. The numeric encoding mode (C) encodes pairs of digits in one symbol. Example: the code "123456" has a symbol count of 3 + 2 + 1 = 6. Some encoders switch modes inside the code using switch symbols to optimize the code length. In this case the exact encoding used is needed to compute the number of symbols.
  • Code 93: The number of symbols corresponds to the number of characters in the code, plus the start and end symbols and 2 checksum digits. Shift characters used in "extended code93" are treated as normal data symbols. Example: the code "ABCDE12345" has a symbol count of 10 + 2 + 2 = 14.
  • Code 39: The number of symbols corresponds to the number of characters in the code, plus the start and end symbols. Note that the start and end symbols are not included in the returned barcode data. Example: the code "4F70050378196356D" ("*4F70050378196356D*") has a symbol count of 17 + 2 = 19.
  • MSI Plessey and Code 25: The number of symbols corresponds to the number of digits in the code. Example: the code "12345674" has a symbol count of 8. For the active symbol count calculation, optional checksum digits are treated like normal data symbols.
  • GS1 DataBar 14: The symbol count corresponds to the number of finder patterns in the code. Each finder is accompanied by two data segments.
  • GS1 DataBar Expanded: The symbol count can not be changed. All lengths defined by the standard are supported.
  • RM4SCC: The number of symbols corresponds to the number of characters in the code, including the checksum character.
  • KIX: The number of symbols corresponds to the number of characters in the code.
  • UPU 4-State: The number of symbols corresponds to the number of code words. Two lengths are supported, 19 or 25 codewords with a maximum number of error correcting codewords of 6 or 12 respectively.
  • Australian Post 4-State: The number of symbol corresponds to 10 digit FCC and DPID codes, and up to 31 characters representing the customer information bar states.