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Re: proposal: background-image-alpha

From: Andrew Fedoniouk <news@terrainformatica.com>
Date: Mon, 8 May 2006 14:26:44 -0700
Message-ID: <002f01c672e6$1b985350$c302000a@internal.toppro.net>
To: "David Woolley" <david@djwhome.demon.co.uk>, <www-style@w3.org>


----- Original Message ----- 
From: "David Woolley" <david@djwhome.demon.co.uk>
To: <www-style@w3.org>


|
| > Reasons: 1) GIF does not support grayscale (needed to serve alpha mask
| > purpose)
|
| GIF does support grayscale to the same resolution as it supports
| RGB (8 bit depth) but without the losses involved in paletisation,
| as the palette can be a trivial, identity palette (0 = #000000,
| 1 = #010101.... 255 = #ffffff).
|

Yes, but it is still RGB value in GIF. So to be able to use it as single alpha 
channel
value you need also to define how this single value produced from *arbitrary* 
RGB GIF.
This RGB to grayscale translation is a subject of holy wars on the Net, like is 
it
luminance or what... And what if this GIF contains transparent color...
It is better to use just PNG and JPEGs (JPEG 2000) with alpha to be short.

Andrew Fedoniouk.
http://terrainformatica.com
Received on Monday, 8 May 2006 21:27:05 GMT

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