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Images disappearing when scrolling with throwprops and blitmask

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I am experiencing a problem with images disappearing while scrolling when using throwprops and blitmask.


This issue only occurs when I scroll dynamically generated content. If I create a movie clip that contains images and text manually using the IDE (Flash CS5.5) and use the exact same code to scroll and throw, the images do not disappear.


Essentially the dynamic content is just an empty movie clip that I add some text fields and load some images into.


Any ideas why the images are disappearing while scrolling and reappearing when the scrolling stops?


My tests suggest it has nothing to do with the throwprops as the problem still occurs when this is removed.

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it sounds like this is related to the BlitMask.


Are you creating your BlitMask before or after you populate your mc with dynamic content. Any time you update the content that Blitmask controls you need to tell BlitMask to update its internal screen capture.


yourBlitMask.update(null, true);



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Thanks Carl for the fast reply.


I create the BlitMask after the mc is populated however changing the update function in my mouseMoveHandler to




does resolve the issue. However the scrolling content now seems very jittery/sluggish on the iPad (testing on an iPad2) (the app I am creating is for iPad only). Note the content is only 4 paragraphs of text and 4 images (each image is 400 pixels by 300 pixels)


I tried just calling




after I create the BlitMask but with just this, the images were still disappearing. Not sure why it should work with the manually created movie clip with the same content and not requiring the extra update parameters but not the dynamically created one.

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Follow up to my previous post. I realised I was creating the Blitmask before the images had loaded into the dynamic content area so putting in a short delay as a test resolved the sluggish issue. I will put some proper code to check all the images have completed loading before creating the blitmask.


So I am glad to have resolved this issue and pleased that Blitmask still rocks!!

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Glad you got it figured and it is working well for you. Thanks for posting the follow-up reports. Its a big help.

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