Re: GdkPixBuf - Byte Order

[calvin softwarelabs org]

Hi Nickolay,

Thank you for the reply. We cann't change the library as we have object
version only and so, will discuss with gtk-devel-list

Regards
Calvin
> ÷ óÒÄ, 18/01/2006 × 17:15 +0800, calvin softwarelabs org ÐÉÛÅÔ:
>> Hello,
>>
>> We are facing some problem with the byte ordering of the GdkPixbuf.
>>
>> In our application, we are using gdk_pixbuf_new(GDK_COLORSPACE_RGB,
>> TRUE,
>> depth, width, height) for getting a GdkPixBuf * and from the pixbuf we
>> are
>> getting the the guchar * picturebuf. We store our image data in the
>> picturebuf in the following order:
>>   picturebuf +  = blue;
>>   picturebuf + 1 = green;
>>   picturebuf + 2 = Red;
>>   picutrebuf + 3 = alpha;
>>
>> But, from the documentation we found that GdkPixBuf uses
>>   picturebuf +  = red;
>>   picturebuf + 1 = green;
>>   picturebuf + 2 = blue;
>>   picturebuf + 3 = alpha;
>>
>> Because of the mismatch in the byte ordering, ie GTK using LSB and our
>> application layer using MSB, we are required to swap byte  and byte 2.
>> Our
>> system is based on Little Endian and GTK version 2.4
>
>> Is there a way to configure the byte ordering in GTK/GDK ? Since I am
>> new
>> to gtk environment, request you to guide me.
>>
>> Thanks and Regards
>> Calvin
>
> That is not a LSB vs MSB problem (it's all about integers, not colors),
> you are using GDK_COLORSPACE_BGR (Blue first. Not yet exists in gtk) and
> create pixbuf with GDK_COLORSPACE_RGB. Since other colorspaces like BGR
> and YUV are not supported by gdk-pixbuf yet, you need to convert data
> manually from your picturebuf.
>
> Are you extensively mixing pixbuf/your library operations? In that case
> it may have sense to modify your library. Another thing is to support
> different colorspaces in gdk-pixbuf. It should not be hard to do I
> think, probably it may have sense to discuss this problem on gtk-devel-
> list and write a patch.
>
>
>
>