if (RectA.Left < RectB.Right && RectA.Right > RectB.Left && RectA.Top > RectB.Bottom && RectA.Bottom < RectB.Top ) or, using Cartesian coordinates (With X1 being left coord, X2 being right coord, increasing from left to right and Y1 being Top coord, and Y2 being Bottom coord, increasing from bottom to top — if this is not … Read more
Eli, the code you’ve settled on is incorrect. A point near the line on which the segment lies but far off one end of the segment would be incorrectly judged near the segment. Update: The incorrect answer mentioned is no longer the accepted one. Here’s some correct code, in C++. It presumes a class 2D-vector … Read more
Calculate the distance between two coordinates by latitude and longitude, including a Javascript implementation. West and South locations are negative. Remember minutes and seconds are out of 60 so S31 30′ is -31.50 degrees. Don’t forget to convert degrees to radians. Many languages have this function. Or its a simple calculation: radians = degrees * … Read more
There’s a nice approach to this problem that uses vector cross products. Define the 2-dimensional vector cross product v × w to be vx wy − vy wx. Suppose the two line segments run from p to p + r and from q to q + s. Then any point on the first line is representable as p + t r (for a scalar parameter t) and any point … Read more
CSS Triangles: A Tragedy in Five Acts As alex said, borders of equal width butt up against each other at 45 degree angles: When you have no top border, it looks like this: Then you give it a width of 0… …and a height of 0… …and finally, you make the two side borders transparent: … Read more