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Amiga computer related discussion => Amiga Software Issues and Discussion => Topic started by: XDelusion on June 04, 2007, 05:00:34 AM

Title: Reducing Image Resolution
Post by: XDelusion on June 04, 2007, 05:00:34 AM
 I have been working on a project for GZDOOM, and thus far, every single windows paint aplication I have tried out has failed me.

 What I am doing is taking screen shots of Jedi Knight II models, and pasting them in the paint program as images.

 What I need to do is DRAMATICALLY reduce the image size from something like 640x480 to something the size of a thumbnail I.E. 64x52.

 The bad part is that no matter what I do, the paint program seems to want to reduce the # of sprites and enlarge the size of the sprites at that.

 So my question I was wondering is if there are any Paint apps for the Amiga that can reduce the resolution of my graphic image without making everything blocky, and destroying all detail? Also if so, would I need to do this on a real Amiga (don't have mine atm) or would doing it under an Emu in Winblows screw things up?

 Thankx in advance.
Title: Re: Reducing Image Resolution
Post by: rkauer on June 04, 2007, 05:10:16 AM
If u are using Windoz, why don't u use the built-in paint editor?:crazy:

Title: Re: Reducing Image Resolution
Post by: XDelusion on June 04, 2007, 05:15:24 AM
Actually the results in MSPAINT come back the same as if I was using Paint Shop or any other commercial program. :)
Title: Re: Reducing Image Resolution
Post by: Piru on June 04, 2007, 07:48:28 AM
Well, some information is bound to be lost if you reduce the resolution that much. There's no way around this.
Title: Re: Reducing Image Resolution
Post by: Thomas on June 04, 2007, 07:48:58 AM
IrfanView (http://www.irfanview.com/) is a Windows app which can change the size with interpolation.

On the Amiga PicShow (http://picshow.ch.to) does a similar job, but not in batch mode, though. SuperView (http://aminet.net/package/gfx/misc/SView5) is another Amiga application which can do any kind of image manipulation.

Of course you can use the Amiga apps both on a real Amiga and in an Amiga emulation, given that the emulation has a complete AmigaOS installed.

However, reducing the image size by a factor of 100 always looses details, although with interpolation it looks much better than without.

Bye,
Thomas
Title: Re: Reducing Image Resolution
Post by: motorollin on June 04, 2007, 08:14:33 AM
If you're using Windows and you can afford it, then I would try Photoshop. I use it all the time to dramatically reduce the size of images. I have created a "90% resize" macro. I then keep clicking it until the picture is the size I want. Reducing it by 90% lots of times seems to lose less quality than reducing it in one hit.

There is also software which plugs in to Photoshop which actually turns your image in to a Fractal algorithm. It can then use this mathematical formula to generate a larger/smaller copy of the image without losing quality. The one that springs to mind is "Genuine Fractals", but their web site focusses on enlarging rather than shrinking pictures. You may want to research this or other apps which do a similar thing.

--
moto
Title: Re: Reducing Image Resolution
Post by: Piru on June 04, 2007, 08:17:00 AM
No algorithm can help. You will lose detail and information when you resize down.

Smart programs can try to retain detail however, but typically this results in in somewhat deformed output, esp with huge size reduce.
Title: Re: Reducing Image Resolution
Post by: motorollin on June 04, 2007, 08:22:27 AM
Well the examples on the Genuine Fractals home page were amazing. The difference between the same resize operation using bicubic resampling compared to Genuine Fractals was like chalk and cheese. Well, it was the same picture, so it was like two very different cheeses :-)

Having said that, there is nothing on there about shrinking the image so I don't know whether this software will help you there.

--
moto
Title: Re: Reducing Image Resolution
Post by: shoggoth on June 04, 2007, 10:01:07 AM
Er... Photoshop has had great image scaling filter since... since forever.

If you don't have it, try GIMP instead. AFAIK it has similar features.

-- Peter
Title: Re: Reducing Image Resolution
Post by: JaXanim on June 04, 2007, 11:27:02 AM
I recommend Photofiltre. It's a nice piece of French freeware and does a brilliant job of size reduction and many other things too. Lots of filters and stuff. A very large size reduction inevitably reduces the resolution, but Photofilre does it very well indeed.

JaX

EDIT: Photofiltre is for Windows
Title: Re: Reducing Image Resolution
Post by: amigean on June 04, 2007, 06:47:27 PM
I used Paint.net recently for a similar operation and got acceptable results. It's open source, is generally a bit slow but it is coming along nicely. Plus Paint.net's relatively basic interface and cut-down features is reminiscent of Amiga programmes :-) . You can get it gere:

http://www.getpaint.net (http://www.getpaint.net)

I don't know if that would help, but if the elements of the picture are reasonably traceable (e.g. as in a sketch) it may make sense to convert it into some sort of vector scalable format and then do any size conversions. While that migh help a bit, Piru is right in saying that there is just far too little space for detail in a 64x52 thumb.

Title: Re: Reducing Image Resolution
Post by: jorkany on June 04, 2007, 08:45:32 PM
Why don't you post a link to the larger image(s) and let people here take a crack at it? I mean, 64x52 is small enough to be pasted in messages as a reply here.
Title: Re: Reducing Image Resolution
Post by: AmiGeezer on June 04, 2007, 09:11:44 PM
Quote

XDelusion wrote:
The bad part is that no matter what I do, the paint program seems to want to reduce the # of sprites and enlarge the size of the sprites at that.


I personally use PaintShopPro - On the resize options, select "Bilinear Resample" or "Bicubic Resample" - the default of "Smart Resize" produces results as you have described.

Try both the above settings and compare the results, different images give better results with one or the other.

Always ensure you keep the aspect ratio when resizing or it will all look very odd.


Cheers,
Matt
Title: Re: Reducing Image Resolution
Post by: DamageX on June 05, 2007, 08:08:59 AM
I made my own DOS program to resize bitmaps some years ago. It works well, but is slow, use as a last resort http://www.hyakushiki.net/xsize12.exe
Title: Re: Reducing Image Resolution
Post by: motrucker on June 05, 2007, 01:29:39 PM
There is a Windows power tools utility that will change resolution as well as anything around, but only gives you three size options. It is worth a try though. It is a really handy routine to have on your computer anyway.
I agree with GIMP most likely being the best choice. It is easily as powerful as photoshop, and it's free!! It is also harder to use however...
How are you getting the screen shots? any way to reduce resolution on the front end??
Title: Re: Reducing Image Resolution
Post by: jmbattle on June 05, 2007, 02:03:01 PM
motorollin,
Quote
Reducing it by 90% lots of times seems to lose less quality than reducing it in one hit.


I'm more than a little skeptical of this claim, as the filtering that Photoshop employs when resizing images will undoubtedly prove to be more destructive when repeated several times.

Kind regards,
James
x
Title: Re: Reducing Image Resolution
Post by: XDelusion on June 06, 2007, 12:54:28 AM
AmiGeezer: You got me going, I thought I had tried those options, but apparently not because the end result looks very acceptable, now I just need to look at it in game and see how it turns out!

 Thank you!

 Thank everyone else for the quick responces and suggestions as well!
Title: Re: Reducing Image Resolution
Post by: JaXanim on June 06, 2007, 01:29:11 AM
Quote

jorkany wrote:
Why don't you post a link to the larger image(s) and let people here take a crack at it? I mean, 64x52 is small enough to be pasted in messages as a reply here.


Great idea! Upload the parent image to some host or other and post the link here. Let's see how all the contenders manage the task. Chocky bickies for the winner!

JaX
Title: Re: Reducing Image Resolution
Post by: XDelusion on June 06, 2007, 07:45:20 AM
I can upload some stuff, would be fun!
Title: Re: Reducing Image Resolution
Post by: AmiGeezer on June 06, 2007, 11:48:05 AM
Quote

XDelusion wrote:
AmiGeezer: You got me going


I have that effect on people!

 :lol:

No probs - glad you got sorted out.

Matt
Title: Re: Reducing Image Resolution
Post by: XDelusion on June 09, 2007, 01:44:00 AM
http://files.frashii.com/~sp00nz/Doom/=work=/StarWarsLegacy/sprites/Trandoshan.rar

Here is one example of the original file, and the smaller version I have made (which still needs to be a wee bit smaller).

 What I am doing is using the Jedi Knight Model viewer, taking screen shots of the models using CONTROL and C, the pastin them into Photo Shop and resizing.

 If anyone can retain quality better than this (with translucent backgrounds) then I'd be all ears, thankx!
Title: Re: Reducing Image Resolution
Post by: JaXanim on June 09, 2007, 11:36:48 AM
@XDelusion

Here's what I got using Photofiltre (freeware) on your large image. The resolution of this (right) and the Photoshop one (left) are the same. Displayed together like this, I don't think there's a great difference, but there is some.
(http://i5.photobucket.com/albums/y191/waveguide/Trandoshan2Custom.png)(http://i5.photobucket.com/albums/y191/waveguide/Trandoshan3.png)
Maybe the right one has a more defined outline and looks very slightly 'slimmer'. This is a difference in antialiasing.
Looking at these magnified in a different viewer, the Photoshop one has less contrast and looks more washed out.
I think the original image needs to be improved to get anything better. It looks like a cut and paste has been done, so there's no antialiasing around the outer edge. This causes Photoshop, etc to do a lot of work on the outline. You may be losing some pixels there. The only way to improve the apparent detail on images this small is to add it manually pixel by pixel.

JaX
Title: Re: Reducing Image Resolution
Post by: Framiga on June 09, 2007, 01:51:28 PM
probably because the one on the right side carries its own background while the other have a transparent background.