Transformations

Add into VobCoorder the following convenience functions:

public int translate(int into, float x, float y) {
    return ortho(into, 0, x, y, 1, 1);
}

public int translate(int into, float x, float y, float z) {
    return ortho(into, z, x, y, 1, 1);
}

public int scale(int into, float x, float y) {
    return ortho(into, 0, 0, 0, x, y);
}

and rename coordsys into ortho.

And into AffineVobCoorder the following functions:

int rotate(int into, float degrees);
int scale(int into, float x, float y, float z);

Also, for all these functions, we should have a shorthand in VobScene:

public int translateCS(int into, Object key, float x, float y);

just to make it a little easier to say them.

For the affine ones, the VobCoorder is cast into AffineVobCoorder, and the error propagated if it's not. A direct cast is not permitted; the functions must check instanceof and then throw NotAffineVobCoorderException, which is a subclass of UnsupportedOperationException.

For all of the above calls which create coordinate systems, have also setParameter calls. This means, for x in translate, scale, rotate, orthoCoordsys, affineCoordsys, the coorder should also have a method

abstract public void setXParams(int id, ...);

for example,

abstract public int ortho(int into, float x, float y, float w, float h); abstract public void setOrthoParams(int id, float x, float y, float w, float h);

Transforming points into coordinate systems

It would be nice to be able to easily transform points to and from coordsystems, since we now have hierarchies. Since the coordsys are known incrementally, it should not be a problem to provide in VobCoorder:

/** Transform one or more points to screen coordinates from the given cs.
 *  Each point is represented as three values (x,y,z) in pt[].
 * @param into The array to store the results in.
 */
public void transformPoints3(int withCS, float[] pt, float[]into) ;

/** Transform one or more points from screen to given CS.
 *  Each point is represented as three values (x,y,z) in pt[].
 * @return True, if a reasonably accurate inverse was found.
 * If an inverse cannot be found, a reasonable attempt shall
 * be made to give a point close (e.g. if an affine transform
 * is singular / near-singular, pick a point on the line
 * that's close to the original.
 */
public boolean inverseTransformPoints3(int withCS, float[] pt, float[]into) ;

At the same time, remove VobCoorder.getRenderInfo as unnecessary.

The reason for allowing the array pt[] to contain several points is simply performance.