On Wednesday, September 14, 2005, 8:15:29 PM, Tonny wrote:

TK> Hi,

>> > Oh, by the way, do you know any way to apply 2D effects like
>> > perspective? Thanks again!
>> 
>>     Perspective is not a 2D effect, it is a 3D effect.  It is
>> difficult to apply Perspective and other weird effects to
>> complex geometry and keep the geometry as 'curves' because the
>> effects do not map spline to spline.  If you are willing to
>> flatten the data then this becomes a simple matter of mapping
>> points.

TK> The most simple ways to fake perspective in 2D, is using strech/skew.
TK> It will fool the human eye, but keep in mind it is not true 3D (z axis
TK> is still missing).

You are both half right. Its a 2.5D effect. You can do it with a 3x3
matrix (but not a 2x3 as used in SVG).

One of the reasons we should have used NURBS rather than sequences of
lines, cubic and quadratic beziers etc is because a perspective
transform of NURB control points is the same as a perspective transform
of the curve itself. Plus you can interpolate two NURBS of
different order.

well, anyway.

TK> Of course if you are applying Thomas technique (mapping point) it will
TK> be better.

TK> Regards
TK> Tonny Kohar




-- 
 Chris Lilley                    mailto:[EMAIL PROTECTED]
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG


---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Reply via email to