Computer Science Canada

Rotating Objects
Author:  Sivann.. [ Thu Nov 06, 2008 5:31 pm ]
Post subject:  Rotating Objects
I'm working on a project for school, and I need to rotate an oval for it. I dont need it to spin, it just needs to be on a different angle. The problem is I don't understand how the variables work for rotating an object. When I try to rotate my oval, it creates a random box that is on that angle? This doesn't make sense. The code I placed is here, as well as the oval im trying to rotate 45 degrees.

var f : int
drawoval (420,70,40,15,11)
var pic : int := Pic.New (50,50,120,45)
var pic45 : int := Pic.Rotate (pic, 45, -1, -1)
Pic.Draw (pic45, 5, 50, picCopy)

The oval i want rotated is: drawoval (420,70,40,15,11)

and yes, i have included: setscreen ("graphics:640,480,nobuttonbar") at the top of my screen.

Help would be very appreciated. Thank You.
Author:  The_Bean [ Thu Nov 06, 2008 7:12 pm ]
Post subject:  Re: Rotating Objects
The problem is that the Pic.New that your creating is not of the oval your trying to rotate.

Draw.Oval (x, y, xRadius, yRadius, Color : int)
where x,y are the center of the circle

Pic.New (x1, y1, x2, y2 : int) : int
where x1,y1 is the bottom left of the pic and x2,y2 is the top right of the pic

In your program:
Your making an oval at (420,70) with a x radius of 40 and y radius of 15.
That oval will go from (380,55) to (460,85) if you were to make a box around it.

So your Pic.New shouldn't be Pic.New(50,50,120,45)
But Pic.New (380,55,460,85)

other than that your Pic.Rotate is working properly
Author:  The_Bean [ Fri Nov 07, 2008 1:50 pm ]
Post subject:  Re: Rotating Objects
There is also this method of actually drawing a rotated oval. Beware

Turing:

View.Set ("graphics:500,500,nobuttonbar,offscreenonly")
type points :
    record
        x, y : int
    end record
var p : array 0 .. 360 of points
for i : 0 .. 360
    p (i).x := round (cosd (i) * 50) + 249
    p (i).y := round (sind (i + 45) * 50) + 249
end for
%Drawing as a FillOval
for i : 0 .. 180
    Draw.Line (p (i).x, p (i).y, p (360 - i).x, p (360 - i).y, 5)
end for
%Drawing as a Oval
for i : 1 .. 360
    Draw.Line (p (i).x, p (i).y, p (i - 1).x, p (i - 1).y, 7)
end for
Author:  Sivann.. [ Sun Nov 09, 2008 8:46 pm ]
Post subject:  RE:Rotating Objects
Thank you soo much.
You saved my project Smile.

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