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Re: [CSS3-color] [css3-images] [css3-transitions] transparent transitions

From: Alan Gresley <alan@css-class.com>
Date: Sun, 10 Jul 2011 23:19:12 +1000
Message-ID: <4E19A6D0.3010908@css-class.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: fantasai <fantasai.lists@inkedblade.net>, www-style@w3.org, Tantek Çelik <tantek@cs.stanford.edu>
On 9/07/2011 4:02 AM, Tab Atkins Jr. wrote:
> On Fri, Jul 8, 2011 at 12:48 AM, Alan Gresley<alan@css-class.com>  wrote:
>> On 29/06/2011 4:27 AM, Tab Atkins Jr. wrote:
>>> On Mon, Jun 27, 2011 at 10:46 AM, fantasai
>>> <fantasai.lists@inkedblade.net>    wrote:
>>>> On 01/12/2011 12:26 PM, Tab Atkins Jr. wrote:

>> So apart from this suggested change affecting transparent-black, any
>> gradient with a transition to transparent-white are also broken along with
>> transitions to the other 16,777,214 transparent color points apart from ones
>> that behaves as a gradients in premultiplied space similar to this one.
>>   linear-gradient(white, rgba(255,255,255,0.0))
> I don't understand what you're trying to say here.

What I am an trying to say is that a very large percentage of potential 
gradient transitions will never work if all gradients are forced to 
transition in premultiplied space.

Please view this test in Firefox 5, IE10 preview 2 or a WebKit nightly.


Now please view the same test in Opera 11.50.

Here are the screenshot for non Opera 11.50 UAs.


Here are the screenshot for Opera 11.50.


>>>> Is there a way to avoid things like this? It seems to me that having
>>>> 'transparent' mean 'transparent black' means you almost never get what
>>>> you want, which is the opacity fading without the color itself changing.
>>>> I think that's a common enough use case that it should be easy to do.
>>> dbaron's got it - Image Values requires gradients to transition in
>>> premultiplied space for precisely this reason.
>> What reason? The supposed reason is based on a problem that never existent.
>> Can you clearly state a problem or an issue?
> The problem is stated clearly in the quote that I was responding to
> there: "having 'transparent' mean 'transparent black' means you almost
> never get what you want... I think that's a common enough use case
> that it should be easy to do.".

How many transparent colors are there?

   rgba(0~255, 0~255, 0-~255, 0.0)

Alan Gresley
Received on Sunday, 10 July 2011 13:19:45 UTC

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