Those changes were exactly what I was referring to. I don't see why we
shouldn't make trimmed arrays when copying the shape. I'm pretty sure
that the copy constructors are going to be overwhelmingly used to make a
protected copy of an existing shape/path2d which is likely meant mostly
for reading. In particular, in the case of the return value from
createStrokedShape() I don't think the intention is to create the shape
and then scribble on it, the intent is to treat the answer as if it were
immutable - at least the 99.9% case - so I think a perfectly sized shape
is OK.
Be sure to add a test case that creates an empty Path2D, clones it, copy
constructs it (to both .Double() and .Float() variants) and then tries
to add new segments to it - to make sure that the array growth code
doesn't get ArrayIndexOutOfBounds exceptions due to making assumptions
about the lengths of the arrays (I eyeballed the makeRoom() code and it
looks good, but we should test it if we are making arrays that are
potentially zero length or very tiny)...
...jim
On 2/24/15 9:58 AM, Laurent Bourgès wrote:
Jim,
Ah, wait, those constructors do copy the arrays without having to iterate the segments and grow the
arrays, but they don't trim them. I'm trying to remember if there was a specific reason that we
decided not to trim the arrays in those constructors, but the only "advantage" I can
think of is that the new copy will have the same potential spare room for growth that the original
had. But that is of questionable value so we should probably just patch the existing
"construct from a Shape" constructors to trim the arrays to the required length instead...
In marlin github, I have the patched Path2D class (not used at runtime):
public Float(Shape s, AffineTransform at) {
super(); // LBO: invoke empty constructor explicitely !
if (s instanceof Path2D) {
Path2D p2d = (Path2D) s;
setWindingRule(p2d.windingRule);
this.numTypes = p2d.numTypes;
// LBO: trim arrays:
this.pointTypes = Arrays.copyOf(p2d.pointTypes,
this.numTypes);
// this.pointTypes = Arrays.copyOf(p2d.pointTypes,
// p2d.pointTypes.length);
this.numCoords = p2d.numCoords;
this.floatCoords = p2d.cloneCoordsFloat(at);
} else {
PathIterator pi = s.getPathIterator(at);
setWindingRule(pi.getWindingRule());
this.pointTypes = new byte[INIT_SIZE];
this.floatCoords = new float[INIT_SIZE * 2];
append(pi, false);
}
}
float[] cloneCoordsFloat(AffineTransform at) {
float ret[];
if (at == null) {
// LBO: trim arrays:
ret = Arrays.copyOf(floatCoords, numCoords);
// ret = Arrays.copyOf(this.floatCoords, this.floatCoords.length);
} else {
// LBO: trim arrays:
ret = new float[numCoords];
// ret = new float[floatCoords.length];
at.transform(floatCoords, 0, ret, 0, numCoords / 2);
}
return ret;
}
What do you think?
FYI my use case in createStrokedShape () is to allocate (and reuse) a
path2d (4k arrays), fill it and then return a new path whose arrays are
trimmed.
Laurent
