Demo Effect:
Click here to download the source file
First find two pictures of the same size
Then put the import into the Flash library, first drag the diagram into the scene to convert to a movie clip named 1 and then insert the key stitch in the 80th stitch
New Layer 2 convert picture 2 to movie clip name 2 drag into the scene put in the 40th stitch then in 40th, 80 pin insert key stitch between them create a motion tween the picture alpha value of the 40th stitch is set to 0
New Layer 3 Create a new movie clip in the scene named 3, named MC in the properties of movie Clip 3. The first stitch in the movie clip draws a high 400-width 10 white rectangle to the left of the canvas. Convert the component width to 0 in the 20th stitch create a motion tween Write code on the 20th Stitch Stop ();
And then a new movie clip 4 is named Mask in the properties of movie clip 4.
Put the movie Clip 3 you just made into the first floor of the movie clip 4.
Create a new layer in the first stitch to write the following code
Now put the movie clip 4 in the 40th stitch in Layer 3, and it's done.