Re: Antialiasing rendering of pixbufs

[Ed Griffiths <edgrif sanger ac uk>]

have you tried using a program like xmag on them to help see the blurring more 
clearly ?

Ed



On Wed, 16 Oct 2013, D M German wrote:

> Hi Damon,
>
> Damon> On Tue, 2013-10-15 at 23:27 -0700, dmg wrote:
> >> I forgot to add. I have been fixing our code to make sure the pixbuf
> >> is always placed in a pixel boundary, with respect to the top,corner
> >> of the canvas.
> >> 
> >> My hypothesis for the blurring is that the scrolling seems  to place
> >> it in an offset of the visible canvas that is a subpixel coordinate,
> >> making it blurry.
> >> 
> >> what would you recommend is a way to fix this?
>
> Damon> I think GooCanvas only scrolls by integer numbers of pixels - it moves
> Damon> around a child GdkWindow to do the scrolling, and that can only be done
> Damon> in pixels.
>
> Damon> So I'm not sure what is causing your problem. Both pictures look a bit
> Damon> blurry to me. Maybe the image is being scaled a tiny bit accidentally?
>
> I thought so originally, so I exported the pixbuf and compared it
> against what is on the screen.
>
> Look at these files:
>
> http://turingmachine.org/~dmg/temp/goocanvas/
>
> original is the pixbuf that is to be rendered.
>
> before is the goocanvas with that pixbuf when it looks "blurry". 
>
> after is the goocanvas with the pibxuf when it looks good. 
>
> I made crops that show it more (see directory crops). The difference is
> subtle. 
>
> The only difference between "before" and "after" is pressing the down key
> twice. I am almost certain we don't do anything when the down key is
> pressed.
>
> thanks again for any insight into this,
>
> --daniel
>
>
> Damon> Damon
>
>
>
> --
> Daniel M. German                  "A coin symbolizes our free will"
>                                   El Zah?r, Jorge Luis Borges
> http://turingmachine.org/
> http://silvernegative.com/
> dmg (at) uvic (dot) ca
> replace (at) with @ and (dot) with .
>
>
> _______________________________________________
> goocanvas-list mailing list
> goocanvas-list gnome org
> https://mail.gnome.org/mailman/listinfo/goocanvas-list

--
 ------------------------------------------------------------------------
| Ed Griffiths, Acedb/ZMap development, Informatics Group,               |
|  The Morgan Building, Sanger Institute, Wellcome Trust Genome Campus   |
|  Hinxton, Cambridge CB10 1HH                                           |
|                                                                        |
| email: edgrif sanger ac uk  Tel: +44-1223-496844  Fax: +44-1223-494919 |
 ------------------------------------------------------------------------


--
The Wellcome Trust Sanger Institute is operated by Genome Research 
Limited, a charity registered in England with number 1021457 and a 
company registered in England with number 2742969, whose registered 
office is 215 Euston Road, London, NW1 2BE.