How can I find the distance between two rectangles? Intersects should return 0 in distance.
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问题:
回答1:
Here's a quick function for calculating distance between two CGRects represented by a CGSize:
CGSize CGSizeDistanceBetweenRects(CGRect rect1, CGRect rect2)
{
if (CGRectIntersectsRect(rect1, rect2))
{
return CGSizeMake(0, 0);
}
CGRect mostLeft = rect1.origin.x < rect2.origin.x ? rect1 : rect2;
CGRect mostRight = rect2.origin.x < rect1.origin.x ? rect1 : rect2;
CGFloat xDifference = mostLeft.origin.x == mostRight.origin.x ? 0 : mostRight.origin.x - (mostLeft.origin.x + mostLeft.size.width);
xDifference = MAX(0, xDifference);
CGRect upper = rect1.origin.y < rect2.origin.y ? rect1 : rect2;
CGRect lower = rect2.origin.y < rect1.origin.y ? rect1 : rect2;
CGFloat yDifference = upper.origin.y == lower.origin.y ? 0 : lower.origin.y - (upper.origin.y + upper.size.height);
yDifference = MAX(0, yDifference);
return CGSizeMake(xDifference, yDifference);
}
回答2:
On a slightly related note, here's how to compute the distance between the centers of two given CGRects:
CGFloat CGRectGetDistanceBetweenCenters( CGRect rect1, CGRect rect2 )
{
CGPoint center1 = CGPointMake( CGRectGetMidX( rect1 ), CGRectGetMidY( rect1 ) );
CGPoint center2 = CGPointMake( CGRectGetMidX( rect2 ), CGRectGetMidY( rect2 ) );
CGFloat horizontalDistance = ( center2.x - center1.x );
CGFloat verticalDistance = ( center2.y - center1.y );
CGFloat distance = sqrt( ( horizontalDistance * horizontalDistance ) + ( verticalDistance * verticalDistance ) );
return distance;
}