Question

I’m a student and i’m new around here. I have a course project to make a Paint-like program. I have a base class Shape with DrawSelf, Contains ect. methods and classes for Rectangle, Ellipse and Triangle for now. Also i have two other classed DisplayProccesor which is class for drawing, and DialogProcessor, which controls the dialog with the user. Theese are requirements for the project.

public class DisplayProcessor
{

    public DisplayProcessor()
    {
    }

    /// <summary>
    /// List of shapes
    /// </summary>
    private List<Shape> shapeList = new List<Shape>();
    public List<Shape> ShapeList
    {
        get { return shapeList; }
        set { shapeList = value; }
    }

    /// <summary>
    /// Redraws all shapes in shapeList
    /// </summary>
    public void ReDraw(object sender, PaintEventArgs e)
    {
        e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
        Draw(e.Graphics);
    }

    public virtual void Draw(Graphics grfx)
    {
        int n = shapeList.Count;
        Shape shape;

        for (int i = 0; i <= n - 1; i++)
        {
            shape = shapeList[i];
            DrawShape(grfx, shape);
        }
    }

    public virtual void DrawShape(Graphics grfx, Shape item)
    {
        item.DrawSelf(grfx);
    }
}

And here`s the other one:

public class DialogProcessor : DisplayProcessor
{
    public DialogProcessor()
    {
    }

    private Shape selection;
    public Shape Selection
    {
        get { return selection; }
        set { selection = value; }
    }

    private bool isDragging;
    public bool IsDragging
    {
        get { return isDragging; }
        set { isDragging = value; }
    }

    private PointF lastLocation;
    public PointF LastLocation
    {
        get { return lastLocation; }
        set { lastLocation = value; }
    }

   public void AddRandomRectangle()
    {
        Random rnd = new Random();
        int x = rnd.Next(100, 1000);
        int y = rnd.Next(100, 600);

        RectangleShape rect = new RectangleShape(new Rectangle(x, y, 100, 200));
        rect.FillColor = Color.White;

        ShapeList.Add(rect);
    }
}

So, i want to rotate one shape, which is selected by the user.
I try like this. It rotates it, but i get this: http://www.freeimagehosting.net/qj3zp

public class RectangleShape : Shape
{

    public override void DrawSelf(Graphics grfx)
    {
        grfx.TranslateTransform(Rectangle.X + Rectangle.Width / 2, Rectangle.Y + Rectangle.Height / 2);
        grfx.RotateTransform(base.RotationAngle);
        grfx.TranslateTransform( - (Rectangle.X + Rectangle.Width / 2), -( Rectangle.Y + Rectangle.Height / 2));
        grfx.FillRectangle(new SolidBrush(FillColor), Rectangle.X, Rectangle.Y, Rectangle.Width, Rectangle.Height);
        grfx.DrawRectangle(Pens.Black, Rectangle.X, Rectangle.Y, Rectangle.Width, Rectangle.Height);
        grfx.ResetTransform();
    }
}

Answer 1

I’ve soleved it! The problem was that i draw selection for each shape and when i rotate the shape, the selection was staying unrotated. I’ve made the same transformation as in DrawSelf method to the selection and everything was fine! Cheers!