Area#add(Area) Optimization

[Philip Race]

I suppose this could be added but it is something an application also 
can easily do for itself.

 >     curves = rhs.curves;

The straight reference, rather than a copy surprised me, but I suppose 
(I am not familiar
with the working of the Area class) that all mutations must create a new 
Vector ...

-phil.


On 2/11/22 3:51 PM, Jeremy Wood wrote:
> I’m working a lot with the Area class lately. Is there any interest in 
> the following optimization?
>
> Area#add(Area) currently resembles:
>
> public void add(Area rhs) {
>   curves = new AreaOp.AddOp().calculate(this.curves, rhs.curves);
>   invalidateBounds();
> }
>
> I propose replacing it with:
>
> public void add(Area rhs) {
>   if (isEmpty()) {
>     curves = rhs.curves;
>   } else if (rhs.isEmpty()) {
>     return;
>   } else {
>     curves = new AreaOp.AddOp().calculate(this.curves, rhs.curves);
>   }
>   invalidateBounds();
> }
>
> If either operand is empty then this is effectively a null op. But the 
> current implementation may still take several seconds to return 
> depending on the complexity of the non-empty operand.
>
> For example the following two snippets of code may have significantly 
> different execution times:
>
> Area sum = new Area();
> for(Shape shape : incomingShapes) {
>   sum.add(new Area(shape));
> }
>
> vs
>
> Area sum = new Area(shapes.get(0));
> for(int a = 1; a < incomingShapes.size(); a++) {
>   Shape shape = incomingShapes.get(a);
>   sum.add(new Area(shape));
> }
>
> And similarly we could review the other operations 
> (subtract/intersect/exclusiveOr/transform) for obvious potential null 
> ops.
>
> If I understand openjdk rules correctly: I'm not authorized to submit 
> an openJDK ticket. Does this interest anyone else on this list enough 
> to submit this as an openJDK ticket? (I'm happy to work on it if I can 
> help.)
>
> Regards,
>  - Jeremy