Hi all,
Sorry my head has been in the sand -- last semester was brutal.
This will be fine, but I am in the last frantic weeks of finishing an
Adirondack hiking book (using lots of good J to overlay GPS info
on topo maps etc) and so didn't catch this thread sooner.
It does sound like image3 was really developed to solve tasks
like the image resizing mentioned. Indeed, automatically creating web
scaled picture galleries was the first main application.
Bicubic is more suited to scaling up (vs down) -- say a poster
oversized print that might become pixelated otherwise.
A sample web sized gallery from the image3 stuff:
http://ww2.lafayette.edu/~reiterc/hikes/misc/2008_01_jt/index.html
Anyway, resize_image from there should suit the need mentioned,
but let me say more.
To read a file, resize, work with than save, consider
load '~addons/media/image3/prevare.ijs'
fn=:'c:\i\2007\11_hike\pict5353.jpg'
$b=:read_image fn
3264 2448 3
$(1024 1024 resize_image b)
1024 768 3
fo=:'c:/temp/temp.jpg'
(1024 1024 resize_image b)write_image fo
195918
resize_image
+-+-+-------------------------------------+
|4|:|szi=.2{.$y |
| | |szo=.<.szi*<./(|.x)%szi |
| | |ind=.(<"0 szi%szo) <[EMAIL PROTECTED]&.> <@i."0 szo|
| | |(<ind){y |
+-+-+-------------------------------------+
The 1024 1024 gives a width height window into which it will fit
the image, respecting the aspect ratio of the original.
To do the same thing, file to file:
1024 1024 mk_th_image fn;fo
195918
To do an entire directory of images, or subset, consider using prevare:
prevare images_in 'c:\i\2007\11_hike\'
Then use "list"-"Full list to group" menu to select all images,
and then select the window size you want with the "web"-"set web size"
menu. Then click the "web html group" button and it will create
web sized versions of all the images in a subdirectory (you will
be prompted for where, but subdirectory of the first image named 'www'
is the default location. In fact, a bit more -- it will also create
thumbnails and an html index showing the thumbnails with clickable links
to the new images.
Hope you find this useful.
Best,
Cliff
Brian Schott wrote:
Ric,
I have used Reiters' fine software and aware of the
rescaling afforded by it. It is a little difficult for me to
extract that single routine from the script suite, so I
thought I would rework the idea for my needs.
I am not familiar with bicubic algorithms and will
look into the link you supplied. Thanks very much.
(B=)
On Mon, 4 Feb 2008, Sherlock, Ric wrote:
+ ---Brian Schott wrote:
+ > I want to rescale
+ > photos that start at about 2000x3000 pixels, to about 1r3
+ > ratio. So approximately 667r2000 would likely give an even
+ > distribution. eg:
+ >
+
+ Maybe you'd be better coding/using one of the image-resampling
+ algorithms - bicubic is supposed to be pretty good I think, maybe
+ someone has one in implemented in J?
+
+ Also, I think there is an image resizing/rescaling verb in Cliff
+ Reiter's image3 addon in JAL.
+
+ This link give some basic ideas of interpolating images.
+ http://www.cambridgeincolour.com/tutorials/image-interpolation.htm
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--
Clifford A. Reiter
Mathematics Department, Lafayette College
Easton, PA 18042 USA, 610-330-5277
http://www.lafayette.edu/~reiterc
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