Affine transforms - matrix algebra

[Dr. Michael Paus]

I am not sure whether this has already been discussed but would it be 
possible
to have a special variant of all constructors and methods, which 
currently take
the full set of matrix elements, which only deal with the 2D subset of 
matrix
elements? This would reduce the number of parameters that you have to
specify in most cases. It would also prevent an issue which I had some time
ago where I specified all elements of a matrix explicitly and when I used
that matrix I lost all anti-aliasing. Don't know if this is still an 
issue and what
the exact circumstances were.

Michael

Am 10.07.2012 17:00, schrieb Pavel Safrata:
> Hello,
> based on previous discussions, we're going to propose a set of new 
> methods to our transforms.
>
> Tracking Jira issue: http://javafx-jira.kenai.com/browse/RT-17942
>
> I hope the names are self-explanatory, otherwise please let me know 
> and I'll provide some description.
>
>
> On Transform class:
>     public Transform getConcatenation(Transform transform) // 
> multiplication
>     public Transform getInverse() throws 
> NoninvertibleTransformException // negation
>     public Transform copy()
>
> Note: in subclasses these methods will be overridden and will return 
> more specific types where possible.
>
>
> On Affine class:
>
> Constructors:
>     public Affine(Transform transform)
>     public Affine(double mxx, double mxy, double mxz, double tx,
>             double myx, double myy, double myz, double ty,
>             double mzx, double mzy, double mzz, double tz)
>
> Setters of the entire matrix:
>     public void setToTransform(Transform t)
>     public void setToTransform(double mxx, double mxy, double mxz, 
> double mxt,
>                              double myx, double myy, double myz, 
> double myt,
>                              double mzx, double mzy, double mzz, 
> double mzt)
>     public void setToIdentity()
>     public void setToTranslation(double tx, double ty)
>     public void setToTranslation(double tx, double ty, double tz)
>     public void setToScale(double sx, double sy)
>     public void setToScale(double sx, double sy, double pivotX, double 
> pivotY)
>     public void setToScale(double sx, double sy, double sz)
>     public void setToScale(double sx, double sy, double sz,
>                            double pivotX, double pivotY, double pivotZ)
>     public void setToRotation(double theta)
>     public void setToRotation(double theta, double pivotX, double pivotY)
>     public void setToRotation(double theta,
>                               double axisX, double axisY, double axisZ,
>                               double pivotX, double pivotY, double 
> pivotZ)
>     public void setToShear(double shx, double shy)
>     public void setToShear(double shx, double shy, double pivotX, 
> double pivotY)
>
> Operations on the matrix (modifying it in place):
>     public void invert() throws NoninvertibleTransformException
>     public void concatenate(Transform t)
>     public void concatenate(double Txx, double Txy, double Txz, double 
> Txt,
>                             double Tyx, double Tyy, double Tyz, double 
> Tyt,
>                             double Tzx, double Tzy, double Tzz, double 
> Tzt)
>     public void preConcatenate(Transform t) // left multiplication
>     public void preConcatenate(double Txx, double Txy, double Txz, 
> double Txt,
>             double Tyx, double Tyy, double Tyz, double Tyt,
>             double Tzx, double Tzy, double Tzz, double Tzt)
>     public void concatWithTranslation(double tx, double ty)
>     public void concatWithTranslation(double tx, double ty, double tz)
>     public void concatWithScale(double sx, double sy)
>     public void concatWithScale(double sx, double sy, double pivotX, 
> double pivotY)
>     public void concatWithScale(double sx, double sy, double sz)
>     public void concatWithScale(double sx, double sy, double sz,
>                                 double pivotX, double pivotY, double 
> pivotZ)
>     public void concatWithRotation(double theta)
>     public void concatWithRotation(double theta, double pivotX, double 
> pivotY)
>     public void concatWithRotation(double theta,
>                               double axisX, double axisY, double axisZ,
>                               double pivotX, double pivotY, double 
> pivotZ)
>     public void concatWithShear(double shx, double shy)
>     public void concatWithShear(double shx, double shy, double pivotX, 
> double pivotY)
>     public void preTranslate(double mxt, double myt)
>     public void preTranslate(double mxt, double myt, double mzt)
>
> Other methods:
>     public double getDeterminant()
>
>
> Notes:
>
> Instead of "concatWithTranslation" it would be more natural to use 
> just "translate" (and similarly for the others), but unfortunately 
> these method names are already taken by the static factory methods on 
> Transform class. This is unpleasant but we need to be backward 
> compatible so we have to introduce different names. We'll be happy to 
> hear better naming suggestions than the concatWith* (which is pretty 
> descriptive I think but not really nice).
>
> To avoid even bigger method explosion this proposal doesn't contain 
> all the convenience "preConcatWith*" methods. However, we added 
> preTranslate, because it is needed quite often (and 
> preConcatWithTranslation looks quite horrible). Any comments to that?
>
> Should rotation axis be passed as Point3D (rather than the three 
> doubles), consistently with Rotate transform?
>
> Would you want static factory methods on Affine (creating Affine 
> instances with the simple transforms)?
>
> Would it be important to you whether or not matrix changes are atomic? 
> If you call one of the methods that modify the entire matrix, can be 
> listeners for each member called immediately as the members are set, 
> or do they need to be called after all the members are updated?
>
> Any missing operations?
>
> Thanks,
> Pavel



-- 
--------------------------------------------------------------------------------------
Dr. Michael Paus, Chairman of the Java User Group Stuttgart e.V. (JUGS).
For more information visit www.jugs.de.