Although it is used in DirectFB, I do not recommend using the Lock/Unlock
functions. They bypass the API, and raise other issues that can be
problematic.
I do not think there is ever a case where using Lock to gain direct access to
the encapsulated pixel data is really necessary - it can always be done using
the standard API. If you explain what you are trying to do then perhaps I can
suggest another way to do it.
==================================
Chris Bore
Training Director
BORES Signal Processing
ch...@bores.com
www.bores.com
+44 (0)1483 740138
________________________________
From: ravi <ravi...@gmail.com>
To: Sriram Neelakandan <sriram.neelakan...@gmail.com>
Cc: directfb-users@directfb.org
Sent: Thu, 23 December, 2010 4:58:32
Subject: Re: [directfb-users] accessing the row
If i unlock the surface first then how can i return the pointer to the caller?
I'm unlocking the surface in a different function that caller will call after
this function.
On Thu, Dec 23, 2010 at 10:02 AM, Sriram Neelakandan
<sriram.neelakan...@gmail.com> wrote:
well that means the surface is already locked .. u must unlock each Lock after
usage
>
>1. Lock
>2. use the pointer
>3. UnLock
>
>
>
>On Wed, Dec 22, 2010 at 4:31 PM, ravi <ravi...@gmail.com> wrote:
>
>Hell,
>> i have a function to implement that returns a pointer to an array
>> of
>>pixels representing the
>>pixels in the specified row of the surface columns from x (inclusive) to x + w
>>(exclusive), I implemented it like this......
>>
>>
>>{ void *data;
>> int pitch;
>> surface->Lock(surface, DSLF_READ, &data, &pitch );
>>
>>
>>return (pointer *)data + pitch*row;
>>
>>
>>}
>>
>>
>>running this function is aborting the program with this message......
>>
>>
>> DirectFBError [>surface->Lock( surface, (DFBSurfaceLockFlags)(DSLF_READ |
>>DSLF_WRITE), &data, &pitch )]: Resource is locked!
>>
>>
>>
>>
>>--
>>Regards
>>
>>Ravi Swami
>>EnMedia Software Technologies
>>Ph +91-974-264-3747
>>
>>_______________________________________________
>>directfb-users mailing list
>>directfb-users@directfb.org
>>http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-users
>>
>>
>
>
>--
>Sriram Neelakandan
>Author - Embedded Linux System Design And Development
>(http://tinyurl.com/2doosu)
>
--
Regards
Ravi Swami
EnMedia Software Technologies
Ph +91-974-264-3747
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