BARCODEREADOPT

typedef struct tagBarCodeReadOpt 
{ 
   L_UINT32 ulSearchType; 
   L_INT nUnits; 
   L_UINT32 ulFlags; 
   L_INT nMultipleMax; 
   RECT rcSearch; 
   L_BOOL bUseRgn; 
   BARCODECOLOR BarColor; 
   BARCODEREADCALLBACK pfnCallback; 
   L_VOID* pUserData; 
} BARCODEREADOPT, *pBARCODEREADOPT; 

This structure contains barcode read options that control the reading process.

Comments

NOTE: Type RSS14 is now GS1 Databar. All references to RSS14 now refer to GS1 Databar.

pBARCODEREADOPT is a pointer to an BARCODEREADOPT structure. Where a function parameter type is pBARCODEREADOPT, you can declare a BARCODEREADOPT variable and pass the variable's address in the parameter. Declaring a pBARCODEREADOPT variable is necessary only if your program requires a pointer.

When the BARCODE_USECOLORS flag is set, then this function will use the BarColor member, otherwise the LBarCode::Read function will ignore it and use the default colors of black for bars and white for spaces are used.

Using colors does not apply for 1 bit per pixel images.

The BARCODE_USECOLORS is used with all barcode kinds.

The BARCODE_RETURNCHECK flag used only with reading linear barcodes.

The smallest Data Matrix symbol size is 40 pixels by 40 pixels. It can be read using BARCODE_DM_READ_SMALL since this enables the reading of Data Matrix symbols that are between 20 to 40 pixels in size.

When reading 2D barcodes, LEADTOOLS can perform internal auto preprocessing using BARCODE_DOUBLE_PASS on the image and try again if the engine cannot detect the barcode required. But this may take extra processing which will increase the barcode detection time. Hence, it is not recommended to always have it enabled except in certain situations:

• The application is reading barcodes of this type exclusively. For example, a dedicated PDF417 reader. Here, always reading the barcode is more important than recognition speed.

• The application uses barcode detection on a server. In this case, the time spent on the actual barcode detection is most probably less than the time required to send the image to the server and get the results back due to network latency. Thus, it makes sense to turn this feature on in this situation.

• The images provided may have a small resolution (DPI) or known to come from a source that does not always provide clean images. For example, a Fax machine or a Scanner. Enabling double pass here ensures that you can read the barcodes regardless on the quality of the input image.

The LEADTOOLS Barcode Demo leaves the option disabled by default.

When the ulFlags member value is set to BARCODE_RETURN_FOUR_POINTS flag, the BARCODEDATA.rcBarLocation member will be updated with the four-point corner encoded values.

Before using the four-point corner encoded values, they must be decoded.

The following example shows how to decode the four-point corner values:

POINT p1, p2, p3, p4;
int nStartX = BarCodeData.rcBarLocation.left;
int nStartY = BarCodeData.rcBarLocation.top;
int nWidth = BarCodeData.rcBarLocation.right - nStartX;
int nHeight = BarCodeData.rcBarLocation.bottom - nStartY;
p1.x = (nStartX & 0xffff);
p1.y = (nStartX >> 16);
p2.x = (nStartY & 0xffff);
p2.y = (nStartY >> 16);
p3.x = (nWidth & 0xffff);
p3.y = (nWidth >> 16);
p4.x = (nHeight & 0xffff);
p4.y = (nHeight >> 16);