Moving a Mask with your Mouse

A mask will limit the view of the layers associated with it. It allows you to place layers above others which can appear like they are below. It also allows you to cut objects so that only portions of them are visible. You will only see what is masked. 

By adding an Action Script you can control the movement of the MASK with your mouse.

Test it out on the right==>

1. Open a new movie set it to 550 x 400 pixels. Set your stage so you can see all of it.

2. Import the picture you want to apply the mask to.

3. Click Insert / Convert to Symbol. Name the symbol "maskedobject". Set to movie clip. Click ok.

4. Open up your Library. Click Windows / Library (f11). Double click on "maskedobject".   Set the registration to x = 0, y = 0. Close "maskedobject".

5. Click Insert / New Symbol. Name the symbol "maskclip". Set to movie clip. Click ok.

6. Drag "maskedobject" onto the stage. Give it an instance name of "mcmaskpic".

7. Add a new layer to "maskclip".  Select first frame.

8. Select your circle tool and draw a in the top left corner of the frame, so only 1/4 of the circle is in the frame.  Fill the circle red.

9. Right click on the time line for layer 2 near the name. Click Mask on the menu.  

10. Close the "maskclip".

11. SAVE your movie !!!

You should now be looking at your blank stage. Scene 1 Layer 1.

12. Drag the "maskclip" onto the stage.

13. Select the 1/4 circle. Open the Actions Panel

• Click + =>Actions=> startDrag
  • Set the target to this
  • Check expression
• Click +=>Actions=> set variable
  • Type in the variable blank posx
  • Set the value to the property _x
  • check expression for _x
• Click +=>Actions=> set variable
  • Type in the variable blank posy
  • Set the value to the property _y
  • check expression for _y
• Click + =>Actions=> onclipevent
  • Change the onclipevent mode from load to enterframe
• Click +=>actions=>set variable
  • type in the variable as  mcmaskpic._x
  • Type in the value as posx -_x
  • Check the expression box
• Click +=>actions=>set variable
  • type in the variable as  mcmaskpic._y
  • Type in the value as posy -_y
  • Check the expression box

Your script should look like this

onClipEvent (load) { startDrag (this, true); posx = _x; posy = _y; } onClipEvent (enterFrame) { mcmaskpic._x = posx-_x; mcmaskpic._y = posy-_y; }

16. Save and Test your movie.