[Bookreader] gnubook/Read-activity update

[Michael Ang]

Sayamindu Dasgupta wrote:
> Hi Raj,
>
> On Wed, Feb 18, 2009 at 10:52 AM, raj kumar <rkumar at archive.org> wrote:
>   
>> The flippy.zip, which is used by the old flipbook, is 3.8 MB.
>> But the jp2.zip, which is used by the new flipbook (GnuBook), is 43.9 MB
>>
>> -raj
>>
>>     
>
> What is the major difference between/advantage over the two formats ?
> Thanks,
> Sayamindu
>   
The JP2s allow access to the full resolution of the source images (this 
isn't true of the JPGs in the flippy.zip).  The JP2 format allows 
efficient retrieval at power of 2 size reductions and we use this 
feature in GnuBook to support zooming in and out.  JP2 also allows 
efficient retrieval of sub-regions of an image which we'd like to use in 
the future to support retrieving large images as a set of tiles (should 
be especially useful in 1-up mode when not all of a page is visible to 
the user).

Best,
  - mang