Question

I created a GuiWindow class that held a texture, title, and rectangle so I can draw the texture and title. I’ve been trying to make it draggable, though I am having a bit of trouble. Originally I had the GuiWindow’s bounds rectangle just lock onto the mouse positions:

if(bounds.contains(MouseHandle.Update()) && MouseHandle.Pressed()) //checks if the bounds rectangle contains the mouse rectangle and the mouse left button is pressed
{
    bounds.X = MouseHandle.Update().X;
    bounds.Y = MouseHandle.Update().Y;
}

which would allow me to drag, though only in a single direction. I then tried

if(bounds.contains(MouseHandle.Update()) && MouseHandle.Pressed())
{
    int offx = bounds.X - MouseHandle.Update().X;
    int offy = bounds.Y - MouseHandle.Update().Y;
    bounds.X = MouseHandle.Update().X + offx;
    bounds.Y = MouseHandle.Update().Y + offy;
}

this time the window just stayed still when I tried dragging. I’m pretty sure I have the basic concept of dragging down. Am I doing something wrong?

Answer 1

Alright this is some code that I’ve been using to move objects with the mouse in some of my XNA applications. Hopefully this will help you with your problem.

//Fields
Texture2D object;
Vector2 object_position;
Rectangle collisionRectangle;
MouseState preMouse;
bool moving = false;
Vector2 mouseOffset;


//initialize fields in LoadContent method
protected override void LoadContent()
{
    object = Content.Load<Texture2D>("nameOfYourImage");
    object_position = new Vector2((graphics.PreferredBackBufferWidth - object.Width)/2, graphics.PreferredBackBufferHeight - object.Height - 60);
    collisionRectangle = new Rectangle((int)object_position.X, (int)object_position.Y, (int)object.Width, (int)object.Height);
}


//add code to Update method



public void MouseInput(MouseState mouse)
{
    if (collsionRectangle.Contains(mouse.X, mouse.Y) && //mouse is over the object
        //the user is clicking the left mousebutton
        mouse.LeftButton == ButtonState.Pressed && 
        //in the previous Update() call the left mousebutton was released, 
        //meaning the user has just clicked the object
        preMouse.LeftButton == ButtonState.Released)
    {
        moving = true;

        //stores what the objects position should be offset by so it doesn't
        //snap to the mouse's position every time you click on it
        mouseOffset = new Vector2(Position.X - mouse.X, Position.Y - mouse.Y);
    }

    if (moving)
    {
        //if the player stops holding down the mousebutton i.e stops moving the object
        if (mouse.LeftButton == ButtonState.Released)  
            moving = false;

        //modifies the position
        Position.X = mouse.X + mouseOffset.X;
        Position.Y = mouse.Y + mouseOffset.Y;

        //prevents object from going off the screen and getting lost
        if (Convert.ToInt32(object_position.X) < 0)
            object_position.X = 0;
        if (object_position.X + object.Width > graphics.PreferredBackBufferWidth)
            object_position.X = graphics.PreferredBackBufferWidth - object.Width;
        if (Convert.ToInt32(object_position.Y) < 0)
            object_position.Y = 0;
        if (object_position.Y + object.Height > graphics.PreferredBackBufferHeight)
            object_position.Y = graphics.PreferredBackBufferHeight - object.Height;

        //updates the collision rectangle
        collisionRectangle = new Rectangle(Postion.X, Position.Y, WIDTH, HEIGHT);
    }

    preMouse = mouse; //stores the current mouseState for use in the next Update() call
}

This will make you able to drag the object with the mouse. Now of course this won’t be directly copyable to your application, as i don’t know how the code of your GuiWindow, but it should be easy to convert to your needs. Hope this helps 🙂