On 11/10/14 2:52 PM, Sergey Bylokhov wrote:
Hi, Jim.
To simply fill a span in the Region, I'll need to open Region.appendSpan()
method,
but I do not want to do it.
No, that method should remain private. All region objects should be
fully constructed at all times when in the hands of calling code.
So I need to create my own EdgesSpanIterator, or totally eliminate
this loop and
return Region object from the TransformHelper directly.
No, all you need is a method:
/**
* (describe edges array - 0,1 are y range, 2N,2N+1 are x ranges, 1 per
y range)
* (dxoff, dyoff are offsets that the edges array values are relative to)
*/
static Region getInstance(int dxoff, int dyoff, int edges[]) {
// copy loop from DrawImage.java here, but use direct manipulation
// of the spans array instead of union operations.
// You should be able to pre-allocate the spans array as well to
// save on growth using appendSpan() et al.
}
That should take only a few minutes to write, then DrawImage simply does:
Region blitclip = Region.getInstance(dx1, dy1, edges);
Probably some logic can be moved from TransformHelper to the java level
(at least generation of edges array). Additionally it will be simpler to
check a performance improvement, because now it is not so obvious
comparing
to the current percents improvement.
Unfortunately the exact calculations to compute the edges array depend
on a lot of calculations done at the native level. This would be a
major repartitioning of the code...
...jim
