How to Get Animations to Work in a PDF
I've been banging my head against a wall all day about using an animation inside a PDF.
I make a frame and have it fly in from right, then export the whole page as SWF with transparent background. Now I delete the animation and place the SWF. Next I put a background in and send it to behind the animation. I set the SWF to play on page load with no poster. Export as interactive PDF.
I thought for sure that transparent background meant, um, transparent! But it's opaque for me. Why can't I get this animated object to fly in over the background?
David is correct in thinking that setting a placed SWF's background to transparent would be honored when you export to a PDF. Unfortunately when you open the exported PDF in Acrobat Pro or Adobe Reader the transparency is not honored. Luckily there is a simple workaround with Acrobat Professional. Just in case you are not familiar working with SWFs and transparent backgrounds inside InDesign, let me explain.
When you create an animation inside InDesign, you can't just export your layout to an interactive PDF and expect your animation to work. In order for an animation to work in a PDF you need to export your animation to a SWF, place it back in the layout and remove/hide the original. After placing the SWF in your layout use the media panel to control the placed SWF file. Set the poster to none and play on page load and. Now you will be able to play back the animation with a transparent background in your layout by using the preview panel.
After exporting to an interactive PDF, you would expect to see a PDF that will play the animation as it did in your layout. Unfortunately, you will see the dreaded white background.
The reason that you are seeing white instead of your background is that InDesign does not render the embedded the SWF file properly inside the exported PDF. You need to edit the placed SWF file with Acrobat Professional. Using the select object tool, double-click the placed SWF file to bring up the SWF options. Check the "transparent background" checkbox and now your PDF will play as expected.
I wish this simple workaround was not necessary, but at least there is a solution. Hopefully at some point in the future the Acrobat and InDesign teams can work together to solve this problem.