如何从Bitmap对象创建Cursor对象？

Question

假设我有一个现有的System.Drawing.Bitmap对象，如何使用与System.Windows.Forms.Cursor对象相同的像素数据创建Bitmap对象？

Answer 1

此答案取自this question。它允许您从Bitmap对象创建Cursor并设置其热点。

public struct IconInfo
{
    public bool fIcon;
    public int xHotspot;
    public int yHotspot;
    public IntPtr hbmMask;
    public IntPtr hbmColor;
}
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetIconInfo(IntPtr hIcon, ref IconInfo pIconInfo);
[DllImport("user32.dll")]
public static extern IntPtr CreateIconIndirect(ref IconInfo icon);

/// <summary>
/// Create a cursor from a bitmap without resizing and with the specified
/// hot spot
/// </summary>
public static Cursor CreateCursorNoResize(Bitmap bmp, int xHotSpot, int yHotSpot)
{
    IntPtr ptr = bmp.GetHicon();
    IconInfo tmp = new IconInfo();
    GetIconInfo(ptr, ref tmp);
    tmp.xHotspot = xHotSpot;
    tmp.yHotspot = yHotSpot;
    tmp.fIcon = false;
    ptr = CreateIconIndirect(ref tmp);
    return new Cursor(ptr);
}


/// <summary>
/// Create a 32x32 cursor from a bitmap, with the hot spot in the middle
/// </summary>
public static Cursor CreateCursor(Bitmap bmp)
{
    int xHotSpot = 16;
    int yHotSpot = 16;

    IntPtr ptr = ((Bitmap)ResizeImage(bmp, 32, 32)).GetHicon();
    IconInfo tmp = new IconInfo();
    GetIconInfo(ptr, ref tmp);
    tmp.xHotspot = xHotSpot;
    tmp.yHotspot = yHotSpot;
    tmp.fIcon = false;
    ptr = CreateIconIndirect(ref tmp);
    return new Cursor(ptr);
}

修改：正如评论中所指出的，当从Cursor句柄创建IntPtr时，处理游标将不发布句柄本身会产生内存泄漏，除非您使用DestroyIcon函数手动释放它：

[DllImport("user32.dll")]
private static extern bool DestroyIcon(IntPtr hIcon);

然后你可以这样调用这个函数：

DestroyIcon(myCursor.Handle);