High memory usage about apv HOT 6 CLOSED

Here are some procmem outputs. You'll see lots of MB allocated in
/dalvik-heap-bitmap/mark/2 and /dev/pmem_camera (strange ? apv does nothing 
with the
camera ?!). On the emulator I see the same leaks except for /dev/pmem_camera. 
The leaks cannot be seen in the DDMS VM heap monitor, so it might be a system 
bug...

Would it be possible to reduce the memory usage by supporting viewing in 
monochrome? For most text PDF document, color is not needed. Further more, APV 
uses RGBA all the time and most devices do RGB565 only. Would this help on the 
rendering performance too?

The change from RGBA to RGB_565 has indeed been made.

I also added a grayscale option.  I don't see any performance improvement with 
it, but I suppose it decreases memory usage.

I also experimented with compressing the tiles.  Using Android's png 
compression was too slow.  But I think that so many pdfs are full of blank 
space that one could write short native-code run-length 
decompression/compression routines that would help a fair amount on most tiles.

This has something to do with image rendering.  On an image-heavy document, I 
see 7-8 mb added to the memory usage each time I go down a page.  This is 
obviously way more than our cache holds.  And it doesn't get freed when you 
load another document.

I think mupdf is caching data.  

I fixed the leaks.  There were three: 
 1. allocation of pages
 2. pdf->glyph_cache
 3. pdf->xref

The big one was pdf->xref->store.  To prevent uncontrolled growth, I now kill 
the store after every tile render.  A better way to proceed would be to age it 
gracefully, but I will leave that for later optimization.