/**
* Propagate dirty region of the layer to other layers in the stack. The method should be called
* for dirty layers only. The dirty layer can be invisible in the case it has been hidden since
* the previous paint.
*
* <p>IMPL_NOTE: The layer been removed or set to invisible state since the previous paint is
* considered as "hidden", thus it should be entirely dirty and must affect other visible layers
* accordingly.
*
* @param le dirty layer element to be propagated to other layers
* @param hidden indicates whether the dirty layer has been hidden since the previous repaint
* @return the highest layer element above le with modified dirty region, or null if none
*/
private CLayerElement sweepAndMarkDirtyLayer(CLayerElement le, boolean hidden) {
if (CGraphicsQ.DEBUG) {
System.err.println("Sweep and mark dirty layer: " + le.getLayer());
}
CLayer l2;
CLayerElement res = null;
CLayer l = le.getLayer();
// Prepare absolute dirty region coordinates of layer l
int dx = l.bounds[X];
int dy = l.bounds[Y];
int dh, dw;
if (l.isEmptyDirtyRegions()) {
dw = l.bounds[W];
dh = l.bounds[H];
} else {
dx += l.dirtyBounds[X];
dy += l.dirtyBounds[Y];
dw = l.dirtyBounds[W];
dh = l.dirtyBounds[H];
}
// Sweep dirty region to upper layers
for (CLayerElement le2 = le.getUpper(); le2 != null; le2 = le2.getUpper()) {
l2 = le2.getLayer();
if (l2.visible) {
if (l2.addDirtyRegion(dx - l2.bounds[X], dy - l2.bounds[Y], dw, dh)) {
// Remember the highest changed layer
res = le2;
}
}
}
// Sweep non-opaque dirty region to undelying layers
if (!l.opaque || hidden) {
for (CLayerElement le2 = le.getLower(); le2 != null; le2 = le2.getLower()) {
l2 = le2.getLayer();
if (l2.visible) {
l2.addDirtyRegion(dx - l2.bounds[X], dy - l2.bounds[Y], dw, dh);
}
}
// A newly hidden layer should be dirty only for the first
// succeeded paint, it should be cleaned as soon as underlying
// layers are properly marked as dirty.
if (hidden) {
l.cleanDirty();
}
}
return res;
}
