// Touch down event handler. /// <summary> /// 输入一个点,判定是否为手势,是则不需要在继续判断,手指离开时,将手势标识设置为false /// 如果不是则继续判断是否为手势. /// </summary> /// <param name="drawingCanvas"></param> /// <param name="e"></param> public void TouchDownHandler(DrawingCanvas drawingCanvas, TouchEventArgs e) { GestureData.Fingers++;//记录手指数 GraphicsPolyLine polyLine; TouchPoint touchPoint = e.GetTouchPoint(drawingCanvas); Point p = touchPoint.Position; if (GestureData.Fingers == 1)//记录第一个手指的基本信息,后后续手势判断使用 { if (!GestureData.IsSignFoFingerOne) { GestureData.IsTouch = true; GestureData.FirstDeviceId = e.TouchDevice.Id; GestureData.FirstFingerBeginPoint = p; GestureData.FirstFingerCurPoint = p; GestureData.IsSignFoFingerOne = true; } } HelperFunctions.IsGesture(drawingCanvas, e);//判断是否为手势 //如果是手势,则将第一个手指画的几何型的Candraw属性置为false,使得后续不在画出来 if (GestureData.IsGesture && GestureData.Fingers == 2 && _activeStrokes.TryGetValue(GestureData.FirstDeviceId, out polyLine)) { polyLine.CanDraw = false; } if (_activeStrokes.TryGetValue(e.TouchDevice.Id, out polyLine)) { FinishStroke(polyLine); return; } //当手指的个数大于2时,将第一个手指与第二个手指的canDraw属性置回true if (!GestureData.IsGesture && GestureData.Fingers > 2) { if (_activeStrokes.TryGetValue(GestureData.FirstDeviceId, out polyLine)) { polyLine.CanDraw = true; } if (_activeStrokes.TryGetValue(GestureData.SecondDeviceId, out polyLine)) { polyLine.CanDraw = true; } } // Create new stroke, add point and assign a color to it. GraphicsPolyLine newPolyLine = new GraphicsPolyLine( new Point[] { p, new Point(p.X + 1, p.Y + 1) }, drawingCanvas.LineWidth, drawingCanvas.ObjectColor, drawingCanvas.ActualScale); newPolyLine.DeviceID = e.TouchDevice.Id; //是手势并且是第二个手指,将其画的几何的CanDraw置为false,不用画 if (GestureData.IsGesture && GestureData.Fingers == 2) { if (!GestureData.IsSignForFingerTwo) { GestureData.SecondDeviceId = e.TouchDevice.Id; GestureData.SecFingerBeginPoint = p; GestureData.StartDistInTwoFingers = HelperFunctions.CalcDistanceSquare(GestureData.FirstFingerBeginPoint, GestureData.SecFingerBeginPoint); GestureData.StartCenterPointInTwoFingers = HelperFunctions.getCenterPoint(GestureData.FirstFingerBeginPoint, GestureData.SecFingerBeginPoint); GestureData.SecFingerCurPoint = p; newPolyLine.CanDraw = false; GestureData.IsSignForFingerTwo = true; if (GestureData.FirstFingerBeginPoint.X < GestureData.SecFingerBeginPoint.X) { GestureData.MaxPositionX = true; } } } //防止已经是手势了,但因为用户不小心使得其他手指不小心碰到了触控,需要使得该误碰的手写内容不画出来 if (GestureData.IsGesture && GestureData.Fingers > 2) { newPolyLine.CanDraw = false; } AddNewObject(drawingCanvas, newPolyLine); // Add new stroke to the collection of strokes in drawing. _activeStrokes[newPolyLine.DeviceID] = newPolyLine; System.Diagnostics.Debug.WriteLine("Touchdown:{0}", GestureData.IsGesture); }