void computeNewRegions(int l, SynthWindows synthwins)
{
// compute update regions
// -> common synthesized part, express in new window coords, to be copied
Window absSynthCached = bufferrgn(l);
Window absSynthNew = synthwins.bufferrgn(l);
Window absOverlap = absSynthCached.overlap(absSynthNew);
Window absValidCached = valid(l).absoluteFrom(bufferrgn(l));
Window absValidNew = synthwins.valid(l).absoluteFrom(synthwins.bufferrgn(l));
Window absValidOverlap = absValidCached.overlap(absValidNew);
Pair <Window, Window> rgn = computeUpdateRegions(absValidNew, absValidOverlap);
m_UpdVert[l] = rgn.first.relativeTo(synthwins.bufferrgn(l));
m_UpdHorz[l] = rgn.second.relativeTo(synthwins.bufferrgn(l));
m_UpdCopySrc[l] = absValidOverlap.relativeTo(bufferrgn(l));
m_UpdCopyDst[l] = absValidOverlap.relativeTo(synthwins.bufferrgn(l));
m_BufferRgn[l] = synthwins.bufferrgn(l);
m_Valid[l] = synthwins.valid(l);
m_Requested[l] = synthwins.requested(l);
m_Cached[l] = synthwins.m_Cached[l];
}
