void distanceDataForNode(FocusDirection direction, const FocusCandidate& current, FocusCandidate& candidate)
{
if (areElementsOnSameLine(current, candidate)) {
if ((direction == FocusDirectionUp && current.rect.y() > candidate.rect.y()) || (direction == FocusDirectionDown && candidate.rect.y() > current.rect.y())) {
candidate.distance = 0;
candidate.alignment = Full;
return;
}
}
IntRect nodeRect = candidate.rect;
IntRect currentRect = current.rect;
deflateIfOverlapped(currentRect, nodeRect);
if (!isRectInDirection(direction, currentRect, nodeRect))
return;
IntPoint exitPoint;
IntPoint entryPoint;
int sameAxisDistance = 0;
int otherAxisDistance = 0;
entryAndExitPointsForDirection(direction, currentRect, nodeRect, exitPoint, entryPoint);
switch (direction) {
case FocusDirectionLeft:
sameAxisDistance = exitPoint.x() - entryPoint.x();
otherAxisDistance = abs(exitPoint.y() - entryPoint.y());
break;
case FocusDirectionUp:
sameAxisDistance = exitPoint.y() - entryPoint.y();
otherAxisDistance = abs(exitPoint.x() - entryPoint.x());
break;
case FocusDirectionRight:
sameAxisDistance = entryPoint.x() - exitPoint.x();
otherAxisDistance = abs(entryPoint.y() - exitPoint.y());
break;
case FocusDirectionDown:
sameAxisDistance = entryPoint.y() - exitPoint.y();
otherAxisDistance = abs(entryPoint.x() - exitPoint.x());
break;
default:
ASSERT_NOT_REACHED();
return;
}
int x = (entryPoint.x() - exitPoint.x()) * (entryPoint.x() - exitPoint.x());
int y = (entryPoint.y() - exitPoint.y()) * (entryPoint.y() - exitPoint.y());
float euclidianDistance = sqrt((x + y) * 1.0f);
// Loosely based on http://www.w3.org/TR/WICD/#focus-handling
// df = dotDist + dx + dy + 2 * (xdisplacement + ydisplacement) - sqrt(Overlap)
float distance = euclidianDistance + sameAxisDistance + 2 * otherAxisDistance;
candidate.distance = roundf(distance);
IntSize viewSize = candidate.visibleNode->document()->page()->mainFrame()->view()->visibleContentRect().size();
candidate.alignment = alignmentForRects(direction, currentRect, nodeRect, viewSize);
}
void distanceDataForNode(FocusDirection direction, Node* start, FocusCandidate& candidate)
{
RenderObject* startRender = start->renderer();
if (!startRender) {
candidate.distance = maxDistance();
return;
}
RenderObject* destRender = candidate.node->renderer();
if (!destRender) {
candidate.distance = maxDistance();
return;
}
IntRect curRect = renderRectRelativeToRootDocument(startRender);
IntRect targetRect = renderRectRelativeToRootDocument(destRender);
// The bounding rectangle of two consecutive nodes can overlap. In such cases,
// deflate both.
deflateIfOverlapped(curRect, targetRect);
// If empty rects or negative width or height, bail out.
if (curRect.isEmpty() || targetRect.isEmpty()
|| targetRect.width() <= 0 || targetRect.height() <= 0) {
candidate.distance = maxDistance();
return;
}
// Negative coordinates can be used if node is scrolled up offscreen.
if (!checkNegativeCoordsForNode(start, curRect)) {
candidate.distance = maxDistance();
return;
}
if (!checkNegativeCoordsForNode(candidate.node, targetRect)) {
candidate.distance = maxDistance();
return;
}
if (!isRectInDirection(direction, curRect, targetRect)) {
candidate.distance = maxDistance();
return;
}
// The distance between two nodes is not to be considered alone when evaluating/looking
// for the best focus candidate node. Alignment of rects can be also a good point to be
// considered in order to make the algorithm to behavior in a more intuitive way.
candidate.alignment = alignmentForRects(direction, curRect, targetRect);
candidate.distance = spatialDistance(direction, curRect, targetRect);
}
