Thorsten Froehlich <tho### [at] trfde> wrote:
: Well, if you look at the images I posted, don't you agree that the result
: looks like it should look like and indeed does look like in image editing
: programs?

  I'm sorry but I don't quite understand.
  What I see in the snapshots you posted is that the version which doesn't
use the alpha channel for preview does something weird. Pixels which are
antialiased against the background use the alpha channel, and the alpha
channel alone, for this. The color of these pixels is _not_ changed due to
antialiasing, but only the proper alpha value is calculated for them.
  This means that if alpha channel is turned off in the preview, the edges
of objects against background should not look smooth (because it's precisely
the alpha channel which makes them smooth, not the color of the pixels).

:  There is no other program that I know that sets the color of
: pixels that are "invisible" to black

  If a pixel is completely transparent, it doesn't really matter what is
its color. It could be black, white, cyan or orange; if it's completely
transparent, then it's completely transparent; the color has no effect
whatsoever.

: and doing so causes lots of problems
: as no other program (that I have) expects it that way.

  What problems?

:  In particular is
: makes the images unusable without alpha channel display always on...

  But that's absolutely normal!
  The alpha channel contains essential information about the image. It tells
how the pixels should be blended against the background in order to get the
correct result. If an image viewing program does not take into account the
alpha channel then it's dropping out this essential information, thus
destroying the original image.
  The image is unusable without alpha channel because it isn't even supposed
to be usable. There isn't anything wrong here.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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