Re: How can I update the gdk-pixbuf raw data?

[Andrey Tsyvarev <tsyvarev ispras ru>]

Hello, Zahra

> Dear Andrey,
>  Thanks alot for your guidance, but when i change the buffer
> data, image header is also changed, and when using
> "gdk_pixbuf_loader_write", an error of "unrecognized image file
> format" will be arised, this is because that the image format is
> important for the loader.
>  is it any way to skip this restriction?
>  Thanks,
>  Zahra Zojaji
  
No, this restriction cannot be skipped - even typed loader(created via
gdk_pixbuf_loader_new_with_type()) need image header for
loading image correctly.

But if you change buffer, can you also adjust header?

By the way, pixbuf itself contains pixels as raw data - array of
rows, each row is array of pixels
(http://library.gnome.org/devel/gdk-pixbuf/stable/gdk-pixbuf-gdk-pixbuf.html).
May be, it is easier to manipulate with pixels of pixbuf itself?
Or create copy of pixbuf, and manipulate with copy. Later you can
synchronize pixbufs using gdk_pixbuf_copy or gdk_pixbuf_copy_area.

>  -----Original Message-----
>  From: Andrey Tsyvarev <tsyvarev ispras ru>
>  To: zzojaji aim com
>  Cc: gtk-app-devel-list gnome org
>  Sent: Fri, 15 May 2009 5:39 pm
>  Subject: Re: How can I update the gdk-pixbuf raw data?
  
    
> Hello, Zahra.    You can use GdkPixbufLoader for retrieve pixbuf
> from raw data.  Code example:    GdkPixbufLoader *loader =
> gdk_pixbuf_loader_new();  gdk_pixbuf_loader_write(loader, buffer,
> buffer_size, NULL);  gdk_pixbuf_loader_close(loader, NULL); 
> GdkPixbuf* pixbuf =     
> gdk_pixbuf_copy(gdk_pixbuf_loader_get_pixbuf(loader)); 
> g_object_unref(loader);        Now 'pixbuf' contains image,
> previously stored in 'buffer'.    If you want to do more complex
> things, than simple restoring pixbuf  from buffer, you may read
> GdkPixbufLoader description
> http://library.gnome.org/devel/gdk-pixbuf/stable/GdkPixbufLoader.html
> > Hello,      >   I am new to GTK and have a problem with
> gdk-pixbuf, How can I update the   pixbuf raw data?   
>   >   There is a pixbuf constructed from an image file, I  want
> to  > change raw data behind it and upload new data back to pixbuf.
> I  am  > using the "gdk_pIxbuf_save_to_buffer" for accessing raw
> data, but I   > don't know how to upload the buffer back to the
> pixbuf!      >   Thanks, in advance,      >   Zahra Zojaji          
> > _______________________________________________  >
> gtk-app-devel-list mailing list  > gtk-app-devel-list gnome org >
> http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list --  
> Andrey Tsyvarev      Linux Verification Center, ISPRAS   web:
> http://www.linuxtesting.org e-mail: tsyvarev ispras ru  
  
  

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-- 
Andrey Tsyvarev
 
 Linux Verification Center, ISPRAS
 web:    http://www.linuxtesting.org
 e-mail: tsyvarev ispras ru