CODEWITHSUNDEEP
c#wpf
Finchsize
Finchsize

Reputation: 935

Rotate a rectangle

I tried to rotate a rectangle when mouse is moving.
My code:

private int i = 0;

private void Canvas_MouseMove(object sender, MouseEventArgs e)
{
    RotateTransform rotation = new RotateTransform();
    rotation.Angle = i;
    rotation.CenterX = Canvas.GetLeft(rect) + rect.Width/2;
    rotation.CenterY = Canvas.GetTop(rect) + rect.Height/2;
    rect.LayoutTransform = rotation;
    i++;         
}

I want to make rotation by center of my rectangle, but it making it in another way. This lines:

rotation.CenterX = Canvas.GetLeft(rect) + rect.Width/2;
rotation.CenterY = Canvas.GetTop(rect) + rect.Height/2;

dont change anything at all. Do you know why ?

I found a solution in another post in this forum, so my solution for this is:

            double left = Canvas.GetLeft(rect);
            double top = Canvas.GetTop(rect);

            Canvas.SetLeft(rect, 0);
            Canvas.SetTop(rect, 0);

            RotateTransform rotation = new RotateTransform();
            rotation.Angle = i;
            rotation.CenterX = rect.Width/2;
            rotation.CenterY = rect.Height/2;
            rect.RenderTransform = rotation;

            Canvas.SetLeft(rect, left);
            Canvas.SetTop(rect, top);
            i++;

Upvotes: 3

Views: 8463

Answers (1)

Clemens
Clemens

Reputation: 128106

I guess what you actually want is a RenderTransform with a RenderTransformOrigin at the center of the Rectangle:

<Rectangle Fill="Orange" Width="100" Height="100" RenderTransformOrigin="0.5,0.5">
    <Rectangle.RenderTransform>
        <RotateTransform x:Name="rotateTransform"/>
    </Rectangle.RenderTransform>
</Rectangle>

Write the MouseMove handler like this:

double angle = 0;

private void Canvas_MouseMove(object sender, MouseEventArgs e)
{
    rotateTransform.Angle = angle; // yes, Angle is a double
    angle += 1;
}

Upvotes: 6

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