Change background color in a movie clip

Hi all,

I have a movie clip with an animation. The animation is a line that at certain point starts moving all the way to its right.
I would like to change the background color (or maybe add a background image) as the line travels to the right .
I suppose that the line has to move to the right and the new background to the left to make the effect that the line is entering in a new color as its travels ...but everything that I try is a wrong try. Can anyone please give me a hand??

Thanks in advance!

Hi, if you wanted it to start on a red background and then as it moves right transition to a blue background (I'm just using some example colors here), all you have to do is create a gradient colored rectangle that covers the full width of your animation.

• Select the rectangle rool on the tool panel (R) and turn off lines in the two color boxes at the bottom. You should just have a straight color fill now.
• Draw a rectangle on the stage.
• With the rectangle selected open the Color panel (Shift-F9) and change the Type dropdown to "Linear". You should now see your rectangle showing a gradient, usually black on the left and white on the right.
• The bottom of the color panel will now show a gradient color. By clicking the little peg on the left (the black one) you can then change the left hand gradient. Same for the right hand one. By clicking at other points between the two you can create new gradient points. For now let's just stick with the two though. For our example we want the left one to be red and the right one to be blue.
• Say the line drawing animation covers two full widths of the stage, you will then need to make the rectangle that wide. You can either do that by selecting the rectangle and manually typing the width value into the width box on the properties panel or you can drag the rectangle corners (or anchor point if you use the transform tool (Q)).
• Now you just need to tween it's animation to match the line i.e. slide from left to right. That could just be a case of having two keyframes; one at the start and one at the end with the first having a shape tween on it's keyframe.

That's the gist of doing it one way.

Thanks Tann! You're awesome!