7.12. Getting a Movie Clip’s Boundaries
Problem
You want to know the minimum and maximum x and y coordinates that determine the edges of a movie clip (its bounding box).
Solution
Use the getBounds( )
method.
Discussion
You can determine the left, right, top, and bottom coordinates of a
movie clip within its parent movie clip using a combination of the
_x
, _y
,
_width
, and _height
properties:
left = myMovieClip._x; right = left + myMovieClip._width; top = myMovieClip._y; bottom = top + myMovieClip._height;
While this technique works, it is rather intensive and inefficient
when compared to the getBounds( )
method. The
getBounds( )
method returns an object with four
properties:
-
xMin
The leftmost x coordinate of the movie clip
-
xMax
The rightmost x coordinate of the movie clip
-
yMin
The topmost y coordinate of the movie clip
-
yMax
The bottommost y coordinate of the movie clip
The four properties define the bounding box of the visible content
within the movie clip. (Note that y coordinates increase as you move
down the screen, which is the opposite of the Cartesian coordinate
system.) When you call getBounds( )
without
parameters, it returns an object with values relative to the movie
clip’s coordinate system. You can also pass the
method a reference to a target coordinate system (another movie clip)
for which you want the returned object’s values to
be given:
// IncludeDrawingMethods.as
from Chapter 4 for itsdrawCircle( )
method. #include "DrawingMethods.as" // Create a new movie clip and draw ...
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