make all the selected animation curves' keys stepped or smoothed (maya command plugin)

naTangentTypeCmd.cpp

/**@file naTangentTypeCmd.cpp
@brief v1.0.0 naTangentTypeCmd -step;   //make all the selected animation curves' keys stepped or smoothed  -smooth
@author Nathaniel O. Anozie (ogbonnawork at gmail dot com)
@note modify at your own risk
*/

//Flags:
//
// -step <string>: whether to use step tangent
//
// -smooth <string>: whether to use smooth tangent
//
//

#include <maya/MPxCommand.h>
#include <maya/MFnPlugin.h>
#include <maya/MGlobal.h>
//for parameter stuff we need this one
#include <maya/MArgList.h>


#include <maya/MItSelectionList.h>
//look in docs what library needed to link to
#include <maya/MItKeyframe.h>             

#define na_Cmd "naTangentTypeCmd"
#define na_Author "Nathaniel Anozie"


class naTangentTypeCmd : public MPxCommand
{
public:
				 naTangentTypeCmd();
    virtual		~naTangentTypeCmd();

    virtual MStatus doIt ( const MArgList& args );

    static void* creator();

private:
    int getTangentTypeIndexFromArg(const MArgList& args, MStatus& stat );

};


void * naTangentTypeCmd::creator() { return new naTangentTypeCmd(); }
naTangentTypeCmd::~naTangentTypeCmd() {}
naTangentTypeCmd::naTangentTypeCmd() {}


//also need
//initializePlugin
//uninitializePlugin
MStatus initializePlugin( MObject obj )
{
    MFnPlugin plugin( obj, na_Author, "8.0", "Any");

    MStatus status = plugin.registerCommand(na_Cmd,
											naTangentTypeCmd::creator );
	if (!status) status.perror("registerCommand");

    return status;
}
MStatus uninitializePlugin( MObject obj )
{
    MFnPlugin plugin( obj );

    MStatus status = plugin.deregisterCommand(na_Cmd);
	if (!status) status.perror("deregisterCommand");

    return status;
}
///////////////////////////////////


/**get the tangent type index to use given user arguments, basically I want rest of script
to know what the user selection was while keeping it separate from doIt
@param reference to user parameter (const MargList& arg)
@param reference to status code    (MStatus& stat)
@result 1 -- step, 2 -- smooth
*/
int naTangentTypeCmd::getTangentTypeIndexFromArg( const MArgList& arg, MStatus& stat)
{
    CHECK_MSTATUS(stat);
    int result = 1;
    stat = MS::kSuccess;
    
    //like MEL string 
    MString parameterMessage = "Required single argument: -smooth ; - step; ";
    
    //like MEL's size using length
    if(arg.length() != 1){ 
        MGlobal::displayInfo( parameterMessage ); 
        stat.perror(parameterMessage);
        stat = MS::kFailure; }
    else{
        //like MEL, param = array[0]
        //
        MString param;
        param = arg.asString(0,&stat);
        MGlobal::displayInfo( param );
        //like MEL's strcmp but we'll use ==
        //dash needed
        if(param == "-smooth"){ result = 2;}
        else if(param == "-step"){ result = 1;  } 
        else{ 
            //tell callee that something went wrong
            //by looking in docs for MStatus could find out these
            stat = MS::kFailure; 
            stat.perror(parameterMessage); 
        }
        
    }
    

    //neat were returning something similar to MEL's usual
    //int
    return result;
}


MStatus naTangentTypeCmd::doIt( const MArgList& arg)
{
    
    MStatus stat = MS::kSuccess;
    
    int tangentTypeChoice = getTangentTypeIndexFromArg( arg, stat );
    CHECK_MSTATUS(stat);
    
    MSelectionList selList;
    
    MGlobal::getActiveSelectionList(selList);
    
    MItSelectionList curveIt(selList,MFn::kAnimCurve); 
    
    while( !curveIt.isDone() )
    {

        MObject myCurve;
        curveIt.getDependNode(myCurve);
                 
        if(!myCurve.isNull())
        {
            //going from animator curve like animCurveTA to its keyframe
            MItKeyframe itKey(myCurve,&stat);
            CHECK_MSTATUS(stat);
            
            if(stat == MS::kSuccess)
            {
                while( !itKey.isDone() )
                {
                    if( tangentTypeChoice == 1 ){
                        stat = itKey.setInTangentType(MItKeyframe::kTangentStep);
                        stat = itKey.setOutTangentType(MItKeyframe::kTangentStep);
                    }
                    else if( tangentTypeChoice == 2 ){
                        
                        stat = itKey.setInTangentType(MItKeyframe::kTangentSmooth);
                        stat = itKey.setOutTangentType(MItKeyframe::kTangentSmooth);
                        stat = itKey.setTangentsLocked(false);
                    }
                    else
                    {
                        stat.perror("Skipping");
                    }
                    
                    CHECK_MSTATUS(stat);
                    
                    itKey.next();
                }
                
                //end is keyframe check  
            }
        }

        
        //increment selected 
        curveIt.next();
        
    }
    
	
	return MS::kSuccess;
}