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Re: getScreenCTM (again)

From: Sigurd Lerstad <sigler@bredband.no>
Date: Sat, 8 Feb 2003 01:37:44 +0100
Message-ID: <035501c2cf0a$4b905d10$591273d5@mmstudio>
To: "Thomas E Deweese" <thomas.deweese@kodak.com>
Cc: <www-svg@w3.org>

>
> Hello Sigurd,
>
>     Sorry for the delay.

That's okay, and thank you.


> SL> Wouldn't it be more useful if getBBox returned the bounding box
> SL> BEFORE any transform, since you can always apply that afterwards
> SL> to the BBox, but you can't unapply it. (or am I missing
> SL> something?)
>
>     You can generally apply the inverse of the transform.

My understanding is that what will no longer give the tightest bounding box.

Say you have an ellipse with a transformation.

A bbox(1) before transformation gives the tightest bbox, you can then
transform each point of that bbox and you get a new bbox after
transformation.

However:

If you only get a bbox(2) after transformation, and you apply inverse
transform to each point of that bbox, then you get a new bbox, but that bbox
will not be the same as bbox(1)

Since you don't keep the transformed points of the bbox around, you keep the
"bounding box" of the transformed points.

(Okay, I'm not sure you understand what I mean :)

--
Sigurd Lerstad
Received on Thursday, 6 February 2003 18:36:39 GMT

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