The transformBy() function is used to apply a 3D transformation matrix to an entity. getTransformedCopy() is used to create a non-database resident transformed copy of entity. It's default implementation clones the entity and calls transformBy(). In custom class it can be overridden. For example OdDbText::transformBy() requires only uni-scaled matrix. But OdDbText::getTransformedCopy() works with non-uniscaled matrix and modifies text width factor.
virtual OdResult OdDbEntity::transformBy( const OdGeMatrix3d& xform );
virtual OdResult OdDbEntity::getTransformedCopy( const OdGeMatrix3d& xform, OdDbEntityPtr& pCopy ) const;
For example, the smiley entity implements:
OdResult AsdkSmiley::transformBy(const OdGeMatrix3d& xform)
{
assertWriteEnabled();
// Transform the center point and get the translation vector
OdGePoint3d oldCenter( center() ),
newCenter( center() );
newCenter.transformBy( xform );
OdGeVector3d transVec = newCenter - center();
// Get the equivalent transformation
OdGeMatrix3d newXform;
newXform.setToTranslation( transVec );
// Only translate the face and mouth - do not transform!
mfacecircle.transformBy( newXform );
mmoutharc.transformBy( newXform );
// Get the point at a quadrant, transform it
OdGePoint3d oldXquad = center() + OdGeVector3d( radius(), 0, 0 ),
newXquad( oldXquad );
newXquad.transformBy( xform );
// ... then scale the Smiley accordingly
if( xform.isEqualTo( OdGeMatrix3d::kIdentity ) == false )
scaleRadius( radius() * newCenter.distanceTo( newXquad ) / oldCenter.distanceTo( oldXquad ));
return eOk;
}
void AsdkSmiley::scaleRadius(const double r) // stretch and constrict of smiley
{
assertWriteEnabled();
OdGePoint3d center( center() );
double rad = radius(),
factor = r / rad;
setEyesApart( factor * eyesApart() );
setEyesHeight( factor * eyesHeight() );
setEyeSize( factor * eyeSize() );
setMouth( mouthLeft().scaleBy( factor, center ),
mouthBottom().scaleBy( factor, center ),
mouthRight().scaleBy( factor, center ) );
setRadius( r );
recordGraphicsModified();
}
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