HALCON Extension Package Programmer's Manual

46 CHAPTER 3. STYLE GUIDE FOR PROGRAMMINGSupply procedures are of type ÀÖÖÓÖ and have only one parameter (a handle of typeÀÔÖÓ ÒÐ for instances of HALCON operators or HALCON threads). Do not forget toreturn an appropriate value at the end of every supply procedure (standard value: À ÅË ÌÊÍ)and every action procedure (standard value À ÅË ÇÃ).Typically, action procedures perform the image processing itself. They should return an errorcode of type ÀÖÖÓÖ as well. It is convenient to implement an action procedure for each pixeltype of image data.3.4 Name Conventions for ProceduresTo ease the interpretation of program code, HALCON introduces some conventions for procedurenames. The most important ones are summarized in the following section.The names of action procedures typically begin with “ÁÈ” (image processing procedure), “ÁÇ”(input/output procedure), or “” (data base procedure). The rest of the name describes thetask performed by the procedure (in english language, beginning with a capital letter). In caseof filters an additional token might be inserted between these two parts of the name encodingthe pixel type(s) of images to be processed, e.g., “”(ÀÌ), “Á”(INT4)or“” (float).Examples:ÁÈÄÓÛÔ×ÁÈÁÌÖ×ÓÐÁÇ×ÔÊÓÒØÌÙÔÐBasic routines performing a small task that might be used by many other routines should startwith “À” (for Help). The leading “H” should be followed by a string encoding the data theroutine works on, e.g., “ÊÄ” for an auxiliary routine processing region data, or “Ä” for routinesworking on XLDs.Examples:ÀÊÄÍÒÓÒÀÄÓÒØÄÒÀÄÓÒØÊÖ××Names of supply procedures start with “” (this stands for Core). The rest is determined bythe name of the underlying action procedure (if there is only one). If there are several actionprocedures whith names differing only by the symbols for different pixel types, the pixel typeis left out in the name of the supply procedure.Examples:ÁÈÄÓÛÔ×ÁÈÌÖ×ÓÐÁÇÇÔÒÏÒÓÛ3.5 Input / OutputExcept explicit IO routines HALCON procedures should not contain any input/output commands,especially no ÔÖÒØ commands. Any interaction should be done either via parametersHALCON Extension Package Interface / 2000-11-16