black block appears while zooming a page

[GoogleCodeExporter]

What steps will reproduce the problem?
1. open a pdf
2. keep zooming the pdf and scroll the pages quickly
3.
What is the expected output? What do you see instead?
After re-rendering the pages should be displayed properly,but sometimes some 
black blocks appears on the screen and sometime they keep on blinking. This 
leads the application to automatically close the pdf and return to file select 
screen.

What version of the product are you using? On what operating system?
Latest version. I am using it on Android 2.3.4(Kindle Fire) 

Please provide any additional information below.

Original issue reported on code.google.com by pratiksa...@gmail.com on 3 Feb 2012 at 7:52

[GoogleCodeExporter]

I have the same problem, but not only when zooming.. also when the page is 
loading.. I have an iconia a500 with android 3.2

Original comment by jtc...@gmail.com on 18 Feb 2012 at 1:58

[GoogleCodeExporter]

Problem also on HTC JetStream with Honeycomb 3.1. After a lot of blocks 
flashing, the app will crash. The app is unusable for me until this gets 
resolved, since I always need to zoom in to read most docs.

Original comment by dp925...@gmail.com on 19 Feb 2012 at 1:30

[GoogleCodeExporter]

same problem of black box when i zoom the pdf file in my sony ericsson walkman 
2.1.

Original comment by sures...@gmail.com on 20 Feb 2012 at 9:47

[GoogleCodeExporter]

Hi all, I got the same issue too. This is due to memory cache limit problem. 
Increase the memory cache in the option, the blinking blocks should be gone. 
This will happen more often on bigger screen device as you zooming with very 
large factor. 

This is just a temporary solution, a better rendering model is needed to avoid 
such problem. 

Original comment by Ncjle...@gmail.com on 5 Mar 2012 at 3:27

[GoogleCodeExporter]

Could you explain more carefully how the problem works?  How far do you need to 
zoom in to generate this problem?  Do you have a sample pdf?

A possible fix would be to set the cache size in a smarter way than is 
currently being done.

Original comment by arpruss on 20 Apr 2012 at 2:40

[GoogleCodeExporter]

Hi, the problem can be observed when I run the application on tablet. When I 
zoom in, the problem occurs. Black box blinking. It occurs when the available 
cache size < memory needed to display the current page. When it is over memory 
limit, certain patches on the rendering page will be deallocated and allocated 
again and again (non stop). And it causes blinking. 

It can be more easily to reproduce with memory cache option disabled + big 
screen + big  zooming. 

Original comment by Ncjle...@gmail.com on 30 Apr 2012 at 3:22

[GoogleCodeExporter]

Setting extra memory cache seems not helpful on tablet. 

In PDFPagesProvider.setMaxCacheSize, it will get the available memory for the 
max cache size. Means:
1. If you set extra memory cache size smaller than available memory(in my case 
it's around 34 MB), PDFPagesProvider uses the available memory as its max.
2. If you set extra memory cache size bigger than available memory, OOM occurs.

And in my opinion, setting max cache size only help the bitmap cache, which 
means when you are scrolling, you get less redraw. The problem of black blocks 
exist in drawing bitmap, eg. everytime I zoom in/out, the black block appears.

Original comment by sebastia...@gmail.com on 29 Aug 2012 at 11:38