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Re: [css-transforms] Making 'transform' match author expectations better with specialized 'rotate'/etc shorthands

From: Shane Stephens <shans@google.com>
Date: Thu, 17 Jul 2014 18:48:29 +1000
Message-ID: <CAGTfzwTgUrdikVB22vCnZnJC_uMRz5Kq4nHM4xk2hRjF26wzuQ@mail.gmail.com>
To: Dean Jackson <dino@apple.com>
Cc: www-style list <www-style@w3.org>, Dirk Schulze <dschulze@adobe.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, Alan Stearns <stearns@adobe.com>
As I've already noted in this thread, I made a mistake here. Please don't
hold that against me, these transform things are tricky :)

TRS is the correct ordering.

Cheers,
    -Shane

On 17 Jul 2014 18:30, "Dean Jackson" <dino@apple.com> wrote:
>
>
> > On 17 Jul 2014, at 3:23 pm, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
> >
> > On Wed, Jul 16, 2014 at 3:06 PM, Shane Stephens <shans@google.com>
wrote:
> >>> As it turns out, you'd actually need to apply these in the order
> >>> translate, scale, rotate to get the result you've pointed out as
natural.
> >>> And it's the fact that even obvious transform wizards like yourself
get this
> >>> wrong which is motivating me to want us to add this affordance
(Francois
> >>> made a very similar point).
> >>
> >> Ah, my bad. I just realized that you have the order correct. Sorry
about
> >> that :) Substitute my confusion for your own.
> >
> > I'm not sure which result he thought was natural
>
> My email didn't say which I thought was natural (FWIW, I think most
people... not all... would be trying to get a rotated rect, not a diamond).
>
> > , or which order he
> > thought was applying - it was unclear from the email
>
> I was applying the order that Shane said. Let's quote him directly:
>
> [[[
>
> > However, there is one ordering for which the local transformations
produce matching global transformations:
> > translate(500px, 200px) scale(1.2, 1.1) rotate(25deg)
>
> > This ordering is clearly special, and clearly has strong advantages for
the purposes of individual rotate, translate and scale properties - the
result of setting these properties will always match across a global and a
local coordinate system.
>
>
> ]]]
>
> At which point I noted this confusion, predicting Tab's mind:
>
> [[[
> (Of course, I applied the transforms in the order you specify below, not
the order in which you described them above. If I'd done them in the order
you describe above, I would get a 200x100 rectangle rotated 45 degrees...
because order matters :)
> ]]]
>
>
> > - but the
> > "rotated rectangle" result is definitely what comes out of my
> > proposal.  The "squished diamond" isn't what you'd get from
> > independent properties; it comes from a TSR ordering.
>
> So I think you Google folk need to get together and work out which is the
magical ordering you are proposing (or which is the muggle). Tab is saying
he expects a rotated rectangle. Shane is saying TSR is the *clearly
special* one. The fact that you don't seem to be able to get it straight is
a concern.
>
> Dean
>
>
Received on Thursday, 17 July 2014 08:48:57 UTC

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