如何在 XNA 游戏中获得 IBeam 光标？

Question

我已经设法让光标在一个简单的 XNA“游戏”中更改为 IBeam，更新为：

protected override void Update(GameTime gameTime)
    {
        // Allows the game to exit
        if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            this.Exit();

        // TODO: Add your update logic here

        if (Keyboard.GetState().IsKeyDown(Keys.A))
        {
            System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Arrow;
        }
        if (Keyboard.GetState().IsKeyDown(Keys.I))
        {
            System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.IBeam;
        }

        base.Update(gameTime);
    }

按下“I”时，鼠标更改为 IBeam 光标，但当您移动鼠标时，立即更改回箭头。有没有办法让它保持默认的 Windows IBeam，或者我需要创建和跟踪自定义光标？

[编辑] 我还应该指出，每帧设置光标都会导致鼠标移动时光标闪烁。似乎 XNA（或 Windows）在每帧内部将光标重置为箭头？

Answer 1

在手动绘制之前，我会尝试设置底层 System.Windows.Forms.Form 的 Cursor 属性：

Form f = (Form)Control.FromHandle(Game.Window.Handle);
f.Cursor = System.Windows.Forms.Cursors.IBeam;

由于我现在没有安装 XNA，所以我不知道这是否可行，或者是否可行它将是永久性的，但我不明白为什么不会。

Answer 2

听起来你必须手动绘制它。它应该不会太难 - 只需通过 SpriteBatch 在光标位置绘制一个精灵即可。

// ex.
protected override void Draw(GameTime gameTime)
{
    // Other stuff...

    base.Draw(gameTime);

    // Retrieve mouse position
    MouseState mState = Mouse.GetState();
    Vector2 mousePos = new Vector2(mState.X, mState.Y);

    // Use this instead to optionally center the texture:
    // Vector2 mousePos = new Vector2(mState.X - cursorTexture.Width / 2, mState.Y - cursorTexture.Height / 2);

    // Draw cursor after base.Draw in order to draw it after any DrawableGameComponents.
    this.spriteBatch.Begin(); // Optionally save state
    this.spriteBatch.Draw(cursorTexture, mousePos, Color.White);
    this.spriteBatch.End();
}

这是一些提取光标图像的代码。请记住，您将需要对 System.Drawing 的额外引用。

protected override void LoadContent()
{
    // Other stuff...

    // The size of the cursor in pixels.
    int cursorSize = 32;

    // Draw the cursor to a Bitmap
    Cursor cursor = Cursors.IBeam;
    Bitmap image = new Bitmap(cursorSize, cursorSize);
    Graphics graphics = Graphics.FromImage(image);
    cursor.Draw(graphics, new Rectangle(0, 0, cursorSize, cursorSize));

    // Extract pixels from the bitmap, and copy into the texture.
    cursorTexture = new Texture2D(GraphicsDevice, cursorSize, cursorSize);
    Microsoft.Xna.Framework.Graphics.Color[] data = new Microsoft.Xna.Framework.Graphics.Color[cursorSize * cursorSize];
    for (int y = 0; y < cursorSize; y++)
    {
        for (int x = 0; x < cursorSize; x++)
        {
            System.Drawing.Color color = image.GetPixel(x, y);
            data[x + y * cursorSize] = new Microsoft.Xna.Framework.Graphics.Color(color.R, color.G, color.B, color.A);
        }
    }
    cursorTexture.SetData<Microsoft.Xna.Framework.Graphics.Color>(data);
}

请记住，这不是我的想法 - 不能保证有效。不过，基本的想法就在那里。