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Re: Problem with Grouping the rotated object.

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Re: Problem with Grouping the rotated object.

Subject: Re: Problem with Grouping the rotated object.
From: Gregory Weston <email@hidden>
Date: Wed, 2 Apr 2008 14:47:06 -0400

Quincey Morris wrote:

On Apr 2, 2008, at 04:00, Ghufran Ahamad wrote:

[xform translateXBy:center.x yBy:center.y];
[xform rotateByDegrees:[curGraphic GetAngle]];
[xform translateXBy:-center.x yBy:-center.y];

This looks kind of wrong. Mathematically, wouldn't you want:

	[xform translateXBy:-center.x yBy:-center.y];
	[xform rotateByDegrees:[curGraphic GetAngle]];
	[xform translateXBy:center.x yBy:center.y];

?

Nope. The way the matrix multiplication works, the effect is that the transformations take place in the opposite order of the way they appeared in code. _______________________________________________

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