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Screen flickering
08-25-2016, 10:42 AM
Post: #1
Screen flickering
Good morning:

I received my new HP Prime a few days ago. I haven't had enough time to review it thoroughly yet. However , I've already noticed an annoying behavior on the screen. Looks like that the screen flickers sometimes. There are some scenarios where you can reproduce this issue. For instance, if you type on the keyboard to enter an expression, some tiny horizontal lines flicker along the screen. This becomes more evident when the history has a lot of text. If You type in the command line on a fresh screen (after clearing the history) there's no flickering at all, or at least it is not visible because the screen is blank. To me, it appears to be something related with the screen refreshing. Somebody told me this is because the system updates directly the screen without using double buffering or so.

So I'm not sure if this means the unit is defective or it's 'usual' behavior because of a not fully debugged design.
I wonder if other users are suffering the same issue.
I'd be grateful if I receive some feedback from users using HP Prime before calling HP for a return.

Details of the calculator:

Software version: 2015 6 17 (8151)
Hardware version: C
CAS Version: 1.1.2-11
Serial number: 4CY4220922
Operating system: V0.037.526

Help Edition: 06 2014

Thanks in advance.
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08-25-2016, 02:54 PM
Post: #2
RE: Screen flickering
(08-25-2016 10:42 AM)penguin Wrote:  Somebody told me this is because the system updates directly the screen without using double buffering or so.

Correct.

There are places in the system that are buffered, and others that are not. So yes, this is normal. It is also something that we'd like to improve/fix at some point as well so it may not stay that was forever.

Quote:because of a not fully debugged design.

Remember that I think it wasn't until V4/4.2 or so of android that they finally got screen flicker/refresh problems corrected there. Up until then, many android handhelds with much more power still had serious problems with tearing, flickering, etc. It isn't always a super easy problem to solve without breaking some things in other ways.

Basically, the reason for this in Prime's case is to avoid problems with long calculations and user programs not updating the screen in a timely manner in different places. For example, you can have long calculations in 1 cell on the spreadsheet and a complete double/triple buffering would prevent any update till that cell finished calculating.



So yes, it is the expected behavior at the moment. Yes, it is on the list to improve/correct/solve. Yes, I do understand the flicker can bother some people to the extreme (and some people are very much more sensitive then others to it).

TW

Although I work for the HP calculator group, the views and opinions I post here are my own.
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08-27-2016, 11:23 AM
Post: #3
RE: Screen flickering
Hello Tim,

Thanks for your authoritative answer. Let's hope HP team will address most, if not all, pending bugs sooner o later.

I'm now the proud owner of two of the most powerful calculators ever made: HP 50g and HP Prime.
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