I would like a downsampling script-fu that follows the following flow:

Gausean Blur radius equals Original size divided by new size which equals GB.

Image blurred with GB,then reduce the size to the new size (straight downsample; no interpolation).

Can add an optional USM, but I would prefer to use my own sharpening technique afterwards.

Currently, I downsample using this method and it appears to help with the aliasing and stuff.

Thanks in advance.

I think i get you.
You want to take an image any size, divide it by your new INPUT size, and use that value for Gaussian blur correct?
Then resize the ORIGINAL image to the INPUT size.
Also do not include Unsharp Mask.
OR
Include an area you can place a value for sharpening with Unsharp Mask?

Am i following you so far?

How about a simple script that you can enter your own GSB and USM in, and then resize it?

Rod, I guess Lylejk suggestion (automatically determining the amount of GaussianBlur) is preferable to the option of inputing it.
As far as my incompetence can understand, in any case it should be a not very complex task for a nice programmer like you Rod, to implement this function, am I wrong?

This is what i get from Lyles post.


Still working on the resize part though.

This image is 2816x2112 and i want it 5 times smaller so i divide by 5 and get 563x422 give or take.
Then i set the hblur and vblur for 5.

Oh i think i got it now.You want the script to calculate the blur radius after you input a new image size right?
So what would be your blur for the above image Lyle?

(2816x2112/5)

Yes; I want the script to apply a guassean blur before downsizing the image (no interpolation). The applied blur before downsizing helps with aliasing issues and such. Again, when I downsize, I do this flow all the time. You can add an unsharp mask afterwards if you want (a little sharpening is necessary), but I prefer using wavelet sharpening (so just rather do that step on my own since sharpening tends to be subjective anyway). Only reason I do downsize is posting images for view at other sites. It's not a critical Script-fu for me, but you all know how lazy I am so why not. lol

Try this one for size Lyle

It appears in a contributed >> Preblur Resize... menu (you can decide where you actually want to put it)


You can tell it not to detect which is bigger - width or height in which case it will use both values you enter.

Kevin

Thanks Kevin; works fine.

Here's a result after I applied wavelet sharpening as the followup (downsized from 2164px to 900px). No aliasing. Happy I am.

It would be interesting to see what the result is if you post an image that this forum doesn't automatically re-size (i.e. max 760px wide)

Kevin

Just to clarify, this forum doesn't physically resize images. Images are dynamically scaled for the display. You can view large images (>760px) at their actual size by clicking the image, then clicking the "full size" square in the Lightbox navigation tab.

I understand that, but the end result is that an image is displayed that has been re-sized using a process that's out of the control of the creator of the image and creators should be aware of that. Obviously in most cases it's not important, but occasionally it will matter.

My point in suggesting Lyle re-size an image to "GimpChat" size was to see if there is any noticeable difference- In Lyle's case I suspect not In the case of some of the (in my opinion) overly large images that get posted here I'm not so sure

Kevin

Again, just to clarify, following the steps I pointed out will result in a display of actual unprocessed, raw image that was uploaded. It's exactly the same as if you right click and select view image. This forum does not physically change the image in any way. Some forum software does physically resize images and even create thumbnails, but this forum doesn't.

Browsers, however, can and will, render images differently than what we see when we view the raw image in GIMP but that is not due to this forum's software.