---------- Forwarded message ----------
From: sunder ramani <[email protected]>
Date: Tue, Jan 20, 2009 at 12:40 PM
Subject: Re: RE : Help reg. Clearing fb/3 screen
To: Ragas sag <[email protected]>


The best way would be create a file filled with your custom values into it
and then cat it dirtectly to the device.

Say a file Black.txt contains the values 0x808080, then you can simply cat
Black.txt > /dev/fbX

This should help!


On Tue, Jan 20, 2009 at 12:37 PM, Ragas sag <[email protected]> wrote:

> Hi Xperts,
>
> I did managed to modify the decode demo code itself. When we are calling
> cleanupDisplayDevice() function, inside it i am resetting all the pixel
> values to " 0x10801080 ". It sets the fb/3 colour to black. But only problem
> it takes a lot of time to set the colour to black and come out of it.
> It takes 3-5 seconds to fill's the screen with black colour. Ideally it
> should be done this way.  Thats lot of time for my application.
>
> Is there a better way to speed up the process by the following code , .i.e
> "
>   for (bufIdx=0; bufIdx < NUM_DISPLAY_BUFS; bufIdx++) {
>         /* Clear the video buffer */
>         buf = (unsigned int *) virtDisplays[bufIdx];
>          for (i=0; i < displaySize / sizeof(unsigned int); i++) {
>          buf[i] = UYVY_BLACK;
>       }
> "
>
> As " cat /dev/zero > /dev/fb/3 " sets the colour as green, any system
> command to change the colour to black ?
>
> Warm Regards,
> Sagar
>
>
> On 1/16/09, sunder ramani <[email protected]> wrote:
>>
>> Hi Sagar,
>>
>> The flushing of the device with the zeros was only a type of workaround.
>> Ideally, you should clear the device buffers by clearing the values in the
>> device buffers which are mapped by the application. It would enable you to
>> clear the device with whatever color of values you want!!
>>
>> Hope this helps!
>>
>> Cheers!
>> Sundar
>>
>> On Fri, Jan 16, 2009 at 7:04 PM, Ragas sag <[email protected]> wrote:
>>
>>> Hi Xperts
>>>
>>> Thank you Sunder for the reply. And i tried as you suggested. It works.
>>> But the screen becomes become blank with green colour ?
>>> Can't it be made black colour?  I tried to see if other than zero do we
>>> have anything in the /dev directory.
>>>
>>> In case if anybody can tell me how to make it black colour, it would he
>>> helpful.
>>>
>>> Warm Regards,
>>> Sagar
>>>
>>> On 1/16/09, sunder ramani <[email protected]> wrote:
>>>>
>>>> Hi Sagar,
>>>>
>>>> The fbset command actually modifies the size of the window and does not
>>>> have any operation on the contents of the window.
>>>>
>>>> For a simple flush, cat /dev/zero > /dev/fb/X should help you to clear
>>>> away the window contents.
>>>>
>>>> Thanx!
>>>> Sundar
>>>>
>>>
>>>
>>
>
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