Hi,
I am working on an AIR app that creates thumbnails from images. For images without an EXIF embedded thumbnail, that means loading the entire image into RAM then scaling down to form the thumbnail. That takes a lot of memory and is slow.
In the Adobe docs related to 'Direct Mipmapping' http://help.adobe.com/en_US/as3/mobile/WS4bebcd66a74275c3-576ba64d124318d7189-7ff7.html
I see the following that makes it sound like the JPEG decompressor can subsample the image w/o loading all of it:
The JPEG decompressor can perform mipmapping within its own format. This direct mipmapping allows a large
bitmap to be decompressed directly to a mipmap format without loading the entire uncompressed image. Generating
the mipmap is substantially faster, and memory used by large bitmaps is not allocated and then freed.
I have looked quite a bit and can't find any samples or documentation for this....
Is this document right? If so how does it work?
Thanks in advance,
Dave