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[Conor Boyd]

My take on this would be these are just resampling artifacts.  Different
sampling algorithms (of which Irfanview provides quite a few) may well
give different results.

If you've got a simple graphic like you describe, I would suggest
decreasing the colour depth to e.g. 16 colours prior to
resizing/resampling, and then you shouldn't find you get subtle
differences in e.g. blue.

Other than that, the resampling results you describe are exactly what I
would expect from a photographic image-manipulating program like
Irfanview (I would content that Irfanview is for manipulating images,
not necessarily graphics - they're different beasts).  I wouldn't expect
Sharpening to solve the problem.  When one talks about sharpening an
image it's probably exactly what you in particular don't want -
sharpening makes the dark side of an edge subtley darker, and the light
side lighter; that's what sharpening means in image-manipulating terms.

In summary I would disagree that this is in any way a "problem" with
Irfanview and it's ilk, but more a matter of expectations.

Hope this helps,

C.

-----Original Message-----
From: delphi-bounces at delphi.org.nz [mailto:delphi-bounces at delphi.org.nz]
On Behalf Of John Bird

The only problem I have struck with Irfanview (and other programs) is in
resizing images:

If I have an image I want to use, I will usually resize it to several
different sizes, some small enough to be used as images on a TBitButton.

If for example the image is Blue, and has a transparent (eg white)
background and is resized smaller, there are a few pixels on and around
the edge of the blue image on the background that get to be averaged to
a light 
blue - in between white and blue.   This is not a problem until the
image is 
shown on a darker background, and the light blue pixels show as a small
ragged bright edge to the image because they are not the transparent
colour any more.

I have experimented with the IrfanView  option "Sharpen after resize"
but this does not quite solve the problem - it seems to sharpen the edge
of bright pixels, and sometimes introduces other oddities.

Anyone else have a way to deal with this?   I have often blown up the 
resized image using Photofiltre (ie view at 800%) and carefully brush
the 
offending edge pixels back to the transparent colour.   Very fiddly!

John

--------------------------------------------------
From: "Conor Boyd" <Conor.Boyd at trimble.co.nz>

> Yeah, Irfanview would be my tool of choice for this sort of task (and 
> many others).
>
> www.irfanview.com
>
> Cheers,
>
> C.
>
> -----Original Message-----
> From: delphi-bounces at delphi.org.nz 
> [mailto:delphi-bounces at delphi.org.nz]
> On Behalf Of John Bird
>
> I think it disappeared in later Delphi,
>
> I use any of IrfanView, PhotoFiltre, Paint.Net   - all freeware -
> Irfanview
> is a converter and viewer, the other two are excellent image editors 
> and convert too.
>
> What do others use?