private void AssertRectangleHasTheFollowingValues(Rectangle rect, int x, int y, int width, int height)
{
Assert.AreEqual(x, rect.X);
Assert.AreEqual(y, rect.Y);
Assert.AreEqual(height, rect.Height);
Assert.AreEqual(width, rect.Width);
}
public Rectangle GetIntersection(Rectangle rect)
{
if (IsPointWithinRectangle(rect.X, rect.Y) || IsPointWithinRectangle(rect.X + rect.Width, rect.Y) ||
IsPointWithinRectangle(rect.X, rect.Y + rect.Height) || IsPointWithinRectangle(rect.X + rect.Width, rect.Y + rect.Height))
{
int x = Math.Max(this.X, rect.X);
int y = Math.Max(this.Y, rect.Y);
int width = Math.Min( (this.X + this.Width), (rect.X + rect.Width)) - x;
int height = Math.Min( (this.Y + this.Height), (rect.Y + rect.Height)) - y;
return new Rectangle(x, y, width, height);
}
else
{
return null;
}
}
public void Rectangle_IntersectsTwoPoints_ReturnsCorrectIntersection()
{
Rectangle compareRect = new Rectangle(8, 11, 10, 3);
Rectangle intersection = rect.GetIntersection(compareRect);
AssertRectangleHasTheFollowingValues(intersection, 10, 11, 8, 3);
}
public void Rectangle_NoIntersection_ReturnsNull()
{
Rectangle compareRect = new Rectangle(1, 1, 1, 1);
Rectangle intersection = rect.GetIntersection(compareRect);
Assert.IsNull(intersection);
}
public void Rectangle_IntersectsOnePoint_ReturnsCorrectIntersection()
{
Rectangle compareRect = new Rectangle(17, 17, 20, 20);
Rectangle intersection = rect.GetIntersection(compareRect);
AssertRectangleHasTheFollowingValues(intersection, 17, 17, 3, 3);
}
public void Rectangle_IntersectOnVerticalLine_Should_ReturnWidthZero_SameHeight()
{
Rectangle compareRect = new Rectangle(0, 10, 10, 10);
Rectangle intersection = rect.GetIntersection(compareRect);
AssertRectangleHasTheFollowingValues(intersection, 10, 10, 0, 10);
}
public void Rectangle_IntersectOnHorizontalLine_ShouldReturnHeightZero_SameWidth()
{
Rectangle compareRect = new Rectangle(10, 8, 10, 2);
Rectangle intersection = rect.GetIntersection(compareRect);
AssertRectangleHasTheFollowingValues(intersection, 10, 10, 10, 0);
}
public void Rectangle_IntersectionIsCompletelyWithinRectangle_ShouldReturnSmallerRectangle()
{
Rectangle compareRect = new Rectangle(11, 11, 6, 6);
Rectangle intersection = rect.GetIntersection(compareRect);
AssertRectangleHasTheFollowingValues(intersection, 11, 11, 6, 6);
}
public void Rectangle_IntersectAtSinglePoint_ShouldReturnHeightWidthAsZero()
{
Rectangle compareRect = new Rectangle(0, 0, 10, 10);
Rectangle intersection = rect.GetIntersection(compareRect);
AssertRectangleHasTheFollowingValues(intersection, 10, 10, 0, 0);
}