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[SVG Transforms 1.0] - Feedback

From: G. Wade Johnson <gwadej@anomaly.org>
Date: Sat, 21 Mar 2009 19:25:37 -0500
To: www-svg@w3.org
Message-ID: <20090321192537.394f0405@sovvan>
Some quick feedback.

1. In section 3. TransformList Extensions, under scale(<sx> [<sy>

This states "If <sy> and <sz>  are not provided, it is assumed to be
equal to <sx>." What is the value of <sz> if <sx> and <sy> are
provided? If all objects are actually 2D, does scaling have any effect
beyond the translation effect due to the Z coordinate scaling?

2. In section 3. TransformList Extensions, under
   rotate(<rotate-angle> <nx> <ny> <nz> [<cx> <cy> <cz>])

An example showing what new construct would be equivalent to the old
rotate might help. (Other than rotateZ( <angle> [<cx> <cy>] )) I guess
I just don't understand the parameters <nx> <ny> <nz>.

3. In section 5. Converting a 4x4 to a 3x3 matrix, paragraph 5, "the
eqation is derived" should be "the equation is derived"

4. General conceptual feedback

I see that the viewing plane is defined as z=0, but I don't see any
mention of whether z increases toward the viewer or away from the

Personally, I see increasing z as getting farther from me, but I could
also argue that larger z should be in front of smaller z. Obviously,
this needs to be specified.

5. General conceptual feedback

What is the visual effect of objects that are in front of the viewing
plane? Are they "behind us" or in front of everything?

Despite these items, this looks really good to me. (I really want
transform-origin right now.<grin/>)

G. Wade
Who knows what email lurks in the hearts of men?
Received on Sunday, 22 March 2009 00:26:19 UTC

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