Making Site Opaque -- This Strategy Feasible?

Ben C schrieb am 27.04.2008 12:23:

On 2008-04-26, Nik Coughlin <nrkn.com (AT) gmail (DOT) com> wrote:
"Prisoner at War" <prisoner_at_war (AT) yahoo (DOT) com> wrote in message
[...]
It doesn't matter that it's CSS 3. All the major browsers support opacity.
IE of course implements it differently, although I think newer versions get
it right, but don't quote me on that.

Opera gets it slightly wrong too, but it doesn't show until you start
nesting opacity contexts.

Here is an obscure example:
http://www.tidraso.co.uk/misc/opacityContexts.html

Firefox gets it right (according to the CSS 3 draft), Opera doesn't.

FF2 does it here exactly the same way like opera 9.2 and 9.5 beta.

--
Mit freundlichen Grüßen
Holger Jeromin

On 2008-04-28, Holger Jeromin <news03_2008 (AT) katur (DOT) de> wrote:

Ben C schrieb am 27.04.2008 12:23:
On 2008-04-26, Nik Coughlin <nrkn.com (AT) gmail (DOT) com> wrote:
"Prisoner at War" <prisoner_at_war (AT) yahoo (DOT) com> wrote in message
[...]
It doesn't matter that it's CSS 3. All the major browsers support opacity.
IE of course implements it differently, although I think newer versions get
it right, but don't quote me on that.

Opera gets it slightly wrong too, but it doesn't show until you start
nesting opacity contexts.

Here is an obscure example:
http://www.tidraso.co.uk/misc/opacityContexts.html

Firefox gets it right (according to the CSS 3 draft), Opera doesn't.

FF2 does it here exactly the same way like opera 9.2 and 9.5 beta.

Are you sure? I have Opera 9.25 on GNU/Linux and it gets it wrong.

You need to look quite closely. Here is an illustration based on a
screenshot of Opera:

http://www.tidraso.co.uk/misc/opacityContexts.png

I have labelled three of the rectangles F, G and H.

G should not be visible through H although F should be. This is because
CSS 3 says "Conceptually, after the element (including its children) is
rendered into an RGBA offscreen image, the opacity setting specifies how
to blend the offscreen rendering into the current composite rendering".
(http://www.w3.org/TR/css3-color/#transparency)

So it should look as though H were first rendered on top of G in an
offscreen image. In that rendering operation, bits of G will be obscured
completely by H. Then the result is blended on top of F, meaning in the
final result you should be able to see F through H but not G through H.

Opera looks like it's just given each element an alpha value equal to
the product of its ancestors' opacities and blended the whole lot
together.

Ben C schrieb am 28.04.2008 09:44:

On 2008-04-28, Holger Jeromin <news03_2008 (AT) katur (DOT) de> wrote:
Ben C schrieb am 27.04.2008 12:23:
On 2008-04-26, Nik Coughlin <nrkn.com (AT) gmail (DOT) com> wrote:
"Prisoner at War" <prisoner_at_war (AT) yahoo (DOT) com> wrote in message
[...]
It doesn't matter that it's CSS 3. All the major browsers support opacity.
IE of course implements it differently, although I think newer versions get
it right, but don't quote me on that.
Opera gets it slightly wrong too, but it doesn't show until you start
nesting opacity contexts.
Here is an obscure example:
http://www.tidraso.co.uk/misc/opacityContexts.html
Firefox gets it right (according to the CSS 3 draft), Opera doesn't.
FF2 does it here exactly the same way like opera 9.2 and 9.5 beta.
Are you sure? I have Opera 9.25 on GNU/Linux and it gets it wrong.
You need to look quite closely. Here is an illustration based on a
screenshot of Opera:

http://www.tidraso.co.uk/misc/opacityContexts.png

I have labelled three of the rectangles F, G and H.

G should not be visible through H although F should be. This is because
CSS 3 says "Conceptually, after the element (including its children) is
rendered into an RGBA offscreen image, the opacity setting specifies how
to blend the offscreen rendering into the current composite rendering".
(http://www.w3.org/TR/css3-color/#transparency)

So it should look as though H were first rendered on top of G in an
offscreen image. In that rendering operation, bits of G will be obscured
completely by H. Then the result is blended on top of F, meaning in the
final result you should be able to see F through H but not G through H.

Opera looks like it's just given each element an alpha value equal to
the product of its ancestors' opacities and blended the whole lot
together.

Sorry, you were right. I did not recognised this little piece :-) :-)

--
Mit freundlichen Grüßen
Holger Jeromin

On Apr 27, 7:00 am, ddailey <ddai... (AT) zoominternet (DOT) net> wrote:

I will confess to not having read all the replies here, and the
example I'll mention is pretty old and probably contains a lot of old-
fashioned stuff, but it (according to my notes) works across browsers:http://srufaculty.sru.edu/david.dail...pacity/opasimp...

cheers
David

Wow, thanks, that's a very interesting page! I've just more or less
"digested" some of the other references others have made...time to
start tinkering with this one!

Thanks again!