Message-ID: <3C6022A3.8040606@huckfinn.de>
Date: Tue, 05 Feb 2002 19:21:23 +0100
From: Alex Weidauer <alex.weidauer@huckfinn.de>
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Subject: Re: Rotate an Ellipse
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TJ wrote:

>I create an object based off of TGraphicControl and I used the TCanvas.Ellipse method to create an ellipse. I would like to give the user the ability to rotate this ellipse. I would also like to give the user the ability after rotating the ellipse to still adjust the size and shape. 
>
>If anyone has any idea about how to go about doing this I would greatly appreciate it.
>
You can use Win32GDI Routines.
It works like this.
   
Procedure RotatedEllipse(aCanvas:TCanvas;X1,Y1,X2,Y2:Integer);
   Var T,O:TXForm; // in unit Windows
Begin..
   SetGraphicsMode(aCanvas.Handle,GM_Advanced);
   GetWorldTransform(aCanvas.Handle,O);
   // Angle in degree
    T.eM11:=1* Cos(w/360*Pi*2);
    T.eM22:=1* Cos(w/360*Pi*2);
    T.eM12:=1* Sin(w/360*Pi*2);
    T.eM21:=1*-Sin(w/360*Pi*2);
    T.eDX:=Round((X1+X2)/2);
    T.eDY:=Round((Y1+Y2))/2);
   ModifyWorldTransform(aCanvas.Handle,T,MWT_LEFTMULTIPLY);
   aCanvas.Ellipse(X1,Y1,X2,Y2)   
   SetWorldTransform(TheDraw.Handle,O);
 End;