13. How to write File translator

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1. File Translator can import and export information from Maya.

2. Creating a file translator requires inheriting from Mpxfiletranslator.

3. Function Description:

(1):: Canbeopened () method determines whether the file translator can open files, if it is just a importer then return flase, and vice versa.

(2) Importer: Must contain:: Havereadmethod (),:: Reader ().

(3) Exporter: Must contain:: Havewritemethod (),:: Writer ().

4. Set translator to allow access to all Mel commands: Set the Requirefullmel parameter value to true in the Mfnplugin::registertranslator () function.

5. Example, a polygon exporter:

classPolyexporter: PublicMpxfiletranslator { Public: Polyexporter (); Virtual~Polyexporter (); VirtualMstatuswriter(Constmfileobject&file,Constmstring&optionsstring, Mpxfiletranslator::fileaccessmode mode); Virtual BOOL         Havewritemethod () const; Virtual BOOLHavereadmethod ()Const; Virtual BOOL           canbeopened () const; VirtualMstring defaultextension ()Const=0; protected:            Virtual BOOLIsVisible (mfndagnode& Fndag, mstatus&status);  Virtual mstatus exportall (ostream& OS);        Virtual mstatus exportselection (ostream& OS); Virtual voidWriteheader (ostream&OS); Virtual voidWritefooter (ostream&OS);  Virtual mstatus Processpolymesh (const Mdagpath dagpath, ostream& OS);  Virtual polywriter* createpolywriter (const Mdagpath dagpath, mstatus& status) = 0 /c1>;};

6. Mfnplugin::registerfiletranslator () function:

There are 6 parameters, the last three are optional,

Status = plugin. Registerfiletranslator("Rawtext", " ", polyrawexporter::creator, " ", "Option1=1", true);

Rawtext:is a name;

Option1=1:default value for the option box for the translator;

True:means that's can use Mglobal::executecommand () method in translator.

7. Reader:

If you want to read the file using the reader () method, the Havereadmethod () method returns True

The reader () method reads each line of the file and returns Ms::kfailture if the read fails

Mstatus Leptranslator::reader (Constmfileobject&file,Constmstring&options, Mpxfiletranslator::fileaccessmode mode) {    ConstMstring fname =File.fullname ();

 mstatus Rval (ms::ksuccess); Const intMaxlinesize =1024x768; CharBuf[maxlinesize];
Ifstream Inputfile (Fname.aschar (), iOS::inch); if(!inputfile) {        //Open FailedCerr << fname <<": Could not being opened for reading\n"; returnms::kfailure; }    if(!inputfile.getline (buf, maxlinesize)) {Cerr<<"file"<< fname <<"contained no lines ... aborting\n"; returnms::kfailure; }
The first line has the magic chars. if(0!=strncmp (buf, Magic.aschar (), Magic.length ())) {Cerr<<"First line of file"<<fname; Cerr<<"Did not contain"<< Magic.aschar () <<". .. aborting\n"; returnms::kfailure; }     while(Inputfile.getline (buf, maxlinesize)) {//processing Each line of the filemstring cmdstring; Cmdstring.Set(BUF); if(!Mglobal::executecommand (cmdstring)) Rval=ms::kfailure;    } inputfile.close (); returnRval;} 　 

8. Writer () method, similar to Reader () method:

Using the Script Editor to provide a message, in this example only the export all and export selection options are provided, the other options will output failure message.

Mstatus Polyexporter::writer (Constmfileobject&file,Constmstring&/*Options*/, mpxfiletranslator::fileaccessmode mode) {        ConstMstring FileName =file.fullname ();ofstream NewFile (Filename.aschar (), iOS:: out); if(!newFile) {mglobal::d isplayerror (FileName+": Could not being opened for reading"); returnms::kfailure; }
NEWFILE.SETF (IOS::UNITBUF); Writeheader (NewFile);
    if(Mpxfiletranslator::kexportaccessmode = = mode) {        if(Mstatus::kfailure = =Exportall (NewFile)) {            returnmstatus::kfailure; }    }     Else if(Mpxfiletranslator::kexportactiveaccessmode = =mode) {        if(Mstatus::kfailure = =exportselection (NewFile)) {            returnmstatus::kfailure; }    }     Else {        returnmstatus::kfailure;    } writefooter (NewFile);    Newfile.flush ();    Newfile.close (); Mglobal::d isplayinfo ("Export to"+ FileName +"successful!"); returnms::ksuccess;}

9. File extention:

Const {    return mstring ("raw");}

Ten. File access mode:

13. How to write File translator