Windows Touch 便笺簿的

Windows Touch 便笺簿的 C# 示例 (MTScratchpadWMTouchCS)

 

本节介绍 Windows Touch 便笺簿的 C# 示例。

Windows Touch 便笺簿的 C# 示例演示如何使用 Windows Touch 消息在窗口上绘制触控点的踪迹。主手指（最先放置到数字化器上的手指）的踪迹是用黑色绘制的。辅助手指的踪迹用其他六种颜色绘制：红色、绿色、蓝色、蓝绿色、洋红色和黄色。下图演示了应用程序在运行时的可能外观。

 

 

 

在此示例中，将创建一个具有触控功能的表单来处理 WM_TOUCH 消息。继承此表单以便在便笺簿应用程序上启用 Windows Touch。当WM_TOUCH 消息传入到此表单时，这些消息将被解释为点并添加到笔画集合中。然后向 Graphics 对象呈现笔画集合。以下代码演示具有触控功能的表单如何注册自身以处理 WM_TOUCH 消息，以及它如何处理 WM_TOUCH 消息。

 

 

private void OnLoadHandler(Object sender, EventArgs e)
        {
            try
            {
                // Registering the window for multi-touch, using the default settings.
                // p/invoking into user32.dll
                if (!RegisterTouchWindow(this.Handle, 0))
                {
                    Debug.Print("ERROR: Could not register window for multi-touch");
                }
            }
            catch (Exception exception)
            {
                Debug.Print("ERROR: RegisterTouchWindow API not available");
                Debug.Print(exception.ToString());
                MessageBox.Show("RegisterTouchWindow API not available", "MTScratchpadWMTouch ERROR",
                    MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1, 0);
            }
        }
(...)
        [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
        protected override void WndProc(ref Message m)
        {
            // Decode and handle WM_TOUCH message.
            bool handled;
            switch (m.Msg)
            {
                case WM_TOUCH:
                    handled = DecodeTouch(ref m);
                    break;
                default:
                    handled = false;
                    break;
            }

            // Call parent WndProc for default message processing.
            base.WndProc(ref m);

            if (handled)
            {
                // Acknowledge event if handled.
                m.Result = new System.IntPtr(1);
            }
        }

以下代码演示如何解释 Windows Touch 消息，以及如何将数据添加到笔画集合中。

 

 

private bool DecodeTouch(ref Message m)
        {
            // More than one touchinput may be associated with a touch message,
            // so an array is needed to get all event information.
            int inputCount = LoWord(m.WParam.ToInt32()); // Number of touch inputs, actual per-contact messages

            TOUCHINPUT[] inputs; // Array of TOUCHINPUT structures
            inputs = new TOUCHINPUT[inputCount]; // Allocate the storage for the parameters of the per-contact messages

            // Unpack message parameters into the array of TOUCHINPUT structures, each
            // representing a message for one single contact.
            if (!GetTouchInputInfo(m.LParam, inputCount, inputs, touchInputSize))
            {
                // Get touch info failed.
                return false;
            }

            // For each contact, dispatch the message to the appropriate message
            // handler.
            bool handled = false; // Boolean, is message handled
            for (int i = 0; i < inputCount; i++)
            {
                TOUCHINPUT ti = inputs[i];

                // Assign a handler to this message.
                EventHandler<WMTouchEventArgs> handler = null;     // Touch event handler
                if ((ti.dwFlags & TOUCHEVENTF_DOWN) != 0)
                {
                    handler = Touchdown;
                }
                else if ((ti.dwFlags & TOUCHEVENTF_UP) != 0)
                {
                    handler = Touchup;
                }
                else if ((ti.dwFlags & TOUCHEVENTF_MOVE) != 0)
                {
                    handler = TouchMove;
                }

                // Convert message parameters into touch event arguments and handle the event.
                if (handler != null)
                {
                    // Convert the raw touchinput message into a touchevent.
                    WMTouchEventArgs te = new WMTouchEventArgs(); // Touch event arguments

                    // TOUCHINFO point coordinates and contact size is in 1/100 of a pixel; convert it to pixels.
                    // Also convert screen to client coordinates.
                    te.ContactY = ti.cyContact/100;
                    te.ContactX = ti.cxContact/100;
                    te.Id = ti.dwID;
                    {
                        Point pt = PointToClient(new Point(ti.x/100, ti.y/100));
                        te.LocationX = pt.X;
                        te.LocationY = pt.Y;
                    }
                    te.Time = ti.dwTime;
                    te.Mask = ti.dwMask;
                    te.Flags = ti.dwFlags;

                    // Invoke the event handler.
                    handler(this, te);

                    // Mark this event as handled.
                    handled = true;
                }
            }

            CloseTouchInputHandle(m.LParam);

            return handled;
        }
    }

以下代码演示如何呈现笔画集合。

 

 

public void Draw(Graphics graphics)
        {
            if ((points.Count < 2) || (graphics == null))
            {
                return;
            }

            Pen pen = new Pen(color, penWidth);
            graphics.DrawLines(pen, (Point[]) points.ToArray(typeof(Point)));
        }

以下代码演示各个笔画对象如何使用 Graphics 对象呈现自己。

 

 

public void Draw(Graphics graphics)
        {
            if(points.Count < 2 || graphics == null)
            {
                return;
            }

            Pen pen = new Pen(color, penWidth);
            graphics.DrawLines(pen, (Point[]) points.ToArray(typeof(Point)));
        }