RSS/Atom feed Twitter
Site is read-only, email is disabled
  1. Chat
  2. Useful links
  3. Polls

Featured content

bad results after rotating a image

This discussion is connected to the gimp-user-list.gnome.org mailing list which is provided by the GIMP developers and not related to gimpusers.com.

This is a read-only list on gimpusers.com so this discussion thread is read-only, too.

2 of 2 messages available
Toggle history

Please log in to manage your subscriptions.
bad results after rotating a image Michael_Hoeller@hugoboss.com 06 Jul 09:14
  bad results after rotating a image Olivier Ripoll 06 Jul 14:29
Michael_Hoeller@hugoboss.com
2006-07-06 09:14:01 UTC (almost 18 years ago)

bad results after rotating a image

Hello experts,

I have a problem with a rotating logo.. (akazia_logo_v5.xcf) -> http://www.agenda21-bad-urach.de/demo.html. I rotated it by 5 degres each over the full 360 cirlce, I scaled it down and indexed the colour (sorry this might not be the correct word in English) and created the gif with 50ms per frame.

Now when you look at the result akazia_logo_v5_ani_demo.gif -> http://www.agenda21-bad-urach.de/demo.html you can easily see how bad it comes out: - the text akazia is no more readable - the "frame" in has got steps when it rotates - at 90 and 270 degre there is a too long gap where nothing is visibable though I have set the 90degre frame to 88 and 270 to 268 resp. -92 degree

I think this are "user" issues I just can not find out by try and error how to make it better. Has someone a hint what I can do? My assumption is not that
nessesarly the downscale is the reason - I think already the induvidal frames could be better. This leads to the question in which size and resolution (dpi)
I need to create the base and if there are does and donts for the rotation to get a better result.
And last: I created 72 frames manually - is there a tool to automate this ???

Thanks a lot
Michael

This e-mail (and/or attachments) is confidential and may be privileged. Use or disclosure of it by anyone other than a designated addressee is unauthorized. If you are not an intended recipient, please delete this e-mail from the computer on which you received it. We thank you for notifying us immediately.

Olivier Ripoll
2006-07-06 14:29:53 UTC (almost 18 years ago)

bad results after rotating a image

Michael_Hoeller@hugoboss.com wrote:

Hello experts,

I have a problem with a rotating logo.. (akazia_logo_v5.xcf) -> http://www.agenda21-bad-urach.de/demo.html. I rotated it by 5 degres each over the full 360 cirlce, I scaled it down and indexed the colour (sorry this might not be the correct word in English) and created the gif with 50ms per frame.

looks fine.

Now when you look at the result akazia_logo_v5_ani_demo.gif -> http://www.agenda21-bad-urach.de/demo.html you can easily see how bad it comes out: - the text akazia is no more readable - the "frame" in has got steps when it rotates

see below for the explanation...

- at 90 and 270 degre there is a too long gap where nothing is visibable though I have set the 90degre frame to 88 and 270 to 268 resp. -92 degree

To me it looks ok. You could make these frames shorter in time or paint the line by hand to give a thickness to the plane.

I think this are "user" issues I just can not find out by try and error how to make it better. Has someone a hint what I can do? My assumption is not that
nessesarly the downscale is the reason - I think already the induvidal frames could be better. This leads to the question in which size and resolution (dpi)

First I thought you had either used a bad downscale ("nearest neighbor" instead of "linear" or "cubic") or a bad indexing (the gif uses only 16 colours), but after playing with your xcf, I understand the problem:

You are trying to make a transparent gif. The problem is due to the gif format. The only way to solve this is to forget about transparency and make any frame opaque with the colour you want to use on the web page. Gif cannot handle real transparency, just a cut-through illusion. You are hitting a fundamental limitation of GIF.

I need to create the base and if there are does and donts for the rotation to get a better result.
And last: I created 72 frames manually - is there a tool to automate this ???

You can script it with script-fu, and perhaps python-fu (depends on your OS, I think it's not yet ready for windows) and perl-fu.

Thanks a lot
Michael

Best regards,

Olivier