Flash 5 Drag Mask Tutorial - Page 4

On the layer named “mask” create the shape, in the example I have used a horizontal rectangle. Bear in mind at this point how many buttons you want on the navigation bar. Make the mask the same size or slightly larger than the buttons so that when you mouse over them the mask fits snugly. Make the mask into a movie clip and call it “mask”.

Now right click the layer called “mask” and mask the layer called “masked”. Preview the movie just to check that it is working properly. If it is you should see the colour picture showing through the mask.

You are about to add the masking movement to the movie clip so unlock all of the layers and do the following calculation:

Take the width of the movie clip picture and divide it by four. This will give you the number of frames to add to the timeline.

In my example the picture is 550 pixels wide so the calculation is 550 / 4 = 137.5. Round this number down to the nearest integer. In my example this will be 137. Now place keyframes at the corresponding number on the timeline. Then select the layer called “mask” and move the mask movie clip to it’s final position at keyframe 137. In my example the mask scrolls from left to right so I moved it to the far right of the movie. Then select frame number 1 and right click it. Select “Create Motion Tween” to make the mask scroll across. If you preview the movie you should see the mask move across the stage revealing the colour picture as it goes across.