Solving the Lag Problem when Working With Large Images

[MoOMoOMiLK]

Hi guys,

I am currently doing a project which involves a lot of interactions with large images (2048 x 1536). The biggest problems I am experiencing is that moving the images around, zooming in/out, and even having the Flash player draw the image (which was already put on stage) cause a bit of a lag. For now the file size is not a concern because I have a preloader but I just want everything to run smoothly after my Flash is loaded. Are there any tips regarding working with large images? (i.e. when to Bitmap cache? How to make the Flash player draw the image faster after the whole Flash is preloaded?)

Thanks in advance.

[snickelfritz]

Movieclips that are transformed, are not good candidates for bitmap caching.
Movieclips that are static or are only translated (such as modifying the xy coordinates) are good candidates for bitmap caching.

Your current problem might stem from the filesize of the background image; reduce it with compression, or reduce the file dimensions in photoshop, then scale it back up in Flash and use compression to further reduce the filesize.
Remove the file or replace it with a tiny substitute image to test this theory.

BTW, be careful; bitmap caching increases the memory overhead in FP.
You might solve a CPU issue and create a new memory issue.

[MoOMoOMiLK]

Thanks for your reply. I am looking into using the BitmapData class to draw my MovieClip and then applying this BitmapData to a Bitmap object, then adding the Bitmap object as a child to the stage. This made a huge improvement in performance. However, I am just wondering if I do it this way, do I still have to set myBitmap.cacheAsBitmap = true?

Also, if I have a stage that is, for example, 500 x 500px, and my image on the stage (at x=0, y=0) is 1000 x 1000px, will it increase the performance if I apply a mask (at x=0, y=0) to my image that is the same dimension as my stage? (Sort of like cropping the image)