Re: Looking for project to work on
On Tue, 9 Mar 1999, Wichert Akkerman wrote:
> Previously Andreas Tille wrote:
> > There I set up a page for the image viewer paul. I split
> > gtkimreg from this project. I have plans to add a widget, say
> > GtkRotate, which lets the user rotate images. There are rotating
> > algorithms in ImageMagick (I had a look at the 4.2 code and have
> > access to the relavant rotating code) or in Gimp.
>
> Are those rotating algorithms which also do subsampling? That takes more
> CPU, but makes the image much better..
I'm not sure, what you mean with subsamplimg. May be it enlightens you id
I cite from the source of ImageMagick-4.2.0/magick/shear.c:
%
% Method RotateImage, XShearImage, and YShearImage is based on the paper
% "A Fast Algorithm for General Raster Rotatation" by Alan W. Paeth,
% Graphics Interface '86 (Vancouver). RotateImage is adapted from a similar
% routine based on the Paeth paper written by Michael Halle of the Spatial
% Imaging Group, MIT Media Lab.
%
...
/*
Perform a fractional rotation. First, shear the image rows.
*/
In general I want to focus on *high quality* rotation and will spend
more CPU time for that purpose. I started writing paul to get the
most of my images and to know *what* the image processing does. So
I'm interested in the highest quality algorithms.
As I said in another mail: If there is some interest in enhancing
paul (libgtkimreg was just split from paul for the stated purpose)
I would like to invite everybody to make it a full featured image
viewer. There could be easily added features but I will only work
on the feautures I need myself. By the way I started using
gettext for internationalisation support (not successful yet) and
so its possibly interesting for common use.
Kind regards
Andreas.
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