// OpenTween - Client of Twitter
// Copyright (c) 2015 kim_upsilon (@kim_upsilon)
// All rights reserved.
//
// This file is part of OpenTween.
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program. If not, see , or write to
// the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
// Boston, MA 02110-1301, USA.
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace OpenTween
{
///
/// コントロールにフォーカスが当たってなくても無理矢理 MouseWheel イベントを発生させるクラス
///
public class MouseWheelMessageFilter : IMessageFilter
{
private readonly List controls = new List();
public MouseWheelMessageFilter()
=> Application.AddMessageFilter(this);
public void Register(Control target)
=> this.controls.Add(target);
public void Unregister(Control target)
=> this.controls.Remove(target);
public bool PreFilterMessage(ref Message m)
{
const int WM_MOUSEWHEEL = 0x020A;
if (m.Msg == WM_MOUSEWHEEL)
{
foreach (var control in this.controls)
{
var details = ParseMessage(m);
var controlRectangle = control.Parent.RectangleToScreen(control.DisplayRectangle);
if (controlRectangle.Contains(details.ScreenLocation))
{
var clientLocation = control.PointToClient(details.ScreenLocation);
var ev = new HandledMouseEventArgs(MouseButtons.None, 0, clientLocation.X, clientLocation.Y, details.WheelDelta);
this.RaiseMouseWheelEvent(control, ev);
// フォーカスが当たっているか否かに関わらず OnMouseWheel イベントを発生させているため、
// 二重にイベントが発生することを防ぐために標準のメッセージ処理は抑制する
return true;
}
}
}
return false;
}
internal class MouseEvent
{
public Point ScreenLocation { get; }
public int WheelDelta { get; }
public MouseEvent(Point location, int delta)
{
this.ScreenLocation = location;
this.WheelDelta = delta;
}
}
internal static MouseEvent ParseMessage(Message m)
{
var screenLocation = new Point((int)(m.LParam.ToInt64() & 0xffffffff));
var wheelDelta = (int)(m.WParam.ToInt64() & 0xffff0000) >> 16;
return new MouseEvent(screenLocation, wheelDelta);
}
public void RaiseMouseWheelEvent(Control control, MouseEventArgs e)
{
var method = typeof(Control).GetMethod("OnMouseWheel", BindingFlags.Instance | BindingFlags.NonPublic);
method.Invoke(control, new[] { e });
}
}
}