ActionScript 3.0 :: Finding X And Y Co-ords At Which Line Hits Movie Clip?

Im making a game, where a player controls a character moving around the screen using the mouse.the player moves using a tween, using the current x y pos and the click x y pos to move the character around here's the thing, i have objects on the screen (such as rocks, etc) that i do not want the user to be able to walk through. i do not want to use hit test to simply chuck the character off the object in real time because that's messy and it would mean the tween continued and stuff.. instead, i want to add some code to the top of the "movePlayer" function that checks to see if an object (such as some rocks) is going to be hit, and if it does, i want the tween to only go to this point (yellow in the below diagram)

Here's what i mean:the player clicks on the screen ( the blue dot) and instead of walking straight to the blue dot, the code determines the point at which the player will hit the big orange block, and only tween to that point, if there are multiple orange blocks in the way, the tween will stop the closest block.