这是个简单的支持多点触摸的画板控件, 绘制功能基于WPF InkCanvas,也是我drawTool系列文章的开篇。
阅读该文章后可能产生一些问题:
1. 如果对生成的笔迹对象进行控制
如果要对生成的stroke笔迹进行控制，这里需要单独用一个基于UIElement的对象关联到笔迹对象，例如Polyline元素的points绑定到stroke的点集合,这样对笔记的对象控制就转化为对UIlement对象的控制了
2. 如何给笔迹对象添加控制边框
在1的基础上给对象添加边框其实就变成给UIElement对象添加边框了，在WPF中可以使用装饰器来实现，包括对对象的控制，例如旋转，拉伸等等
ps:1，2问题会在后面文章实现~ 上个简单的图~
/// PenType = 画笔类型，支持普通画笔，荧光笔，点擦除,后面我扩充到支持图像笔，纹理笔以及flash笔，至于排笔的实现其实只要上何止width和height不同就可以了
/// PenColor = 画笔的颜色
/// EraseWidth = 橡皮擦粗细
直接上源码，代码理解起来还是很简单的(MultiTouchCanvas)
/// <summary>
/// 支持多点触摸的InkCanvas
/// </summary
public class MultiTouchCanvas : FrameworkElement
{
private InkCanvasProxy _inkCanvas = new InkCanvasProxy();
private Grid transparentOverlay = new Grid();
private StrokeType _strokeType = StrokeType.Stroke;
private Dictionary<object, StrokeCollection> _strokes = new Dictionary<object, StrokeCollection>();
private Dictionary<object, Stroke> _currentStroke = new Dictionary<object, Stroke>(); private Color _penColor = Colors.Green;
public Color PenColor{
get{
return this._inkCanvas.DefaultDrawingAttributes.Color;
}
set{
this._penColor = value;
this._inkCanvas.DefaultDrawingAttributes.Color = value;
if (this.PenType == StrokeType.HighlighterStroke)
{
value.ScA = System.Convert.ToSingle(0.5);
this._inkCanvas.DefaultDrawingAttributes.Color = value;
}
}
} private double _penWidth = 4.0;
public double PenWidth
{
get { return this._penWidth; }
set
{
this._penWidth = value;
this._inkCanvas.DefaultDrawingAttributes.Width = value;
this._inkCanvas.DefaultDrawingAttributes.Height = value;
}
} private double _eraseWidth = 30.0;
public double EraseWidth
{
get
{
return this._eraseWidth;
}
set
{
this._eraseWidth = value;
this._inkCanvas.DefaultDrawingAttributes.Height = value;
this._inkCanvas.DefaultDrawingAttributes.Width = value;
}
} public StrokeType PenType
{
get { return this._strokeType; }
set
{
this._strokeType = value;
if (this._strokeType == StrokeType.Stroke || this._strokeType == StrokeType.HighlighterStroke)
{
this._inkCanvas.EditingMode = InkCanvasEditingMode.Ink;
this._inkCanvas.DefaultDrawingAttributes.Width = this.PenWidth;
this._inkCanvas.DefaultDrawingAttributes.Height = this.PenWidth;
this._inkCanvas.DefaultDrawingAttributes.Color = this.PenColor;
} if (this._strokeType == StrokeType.HighlighterStroke)
{
Color dColor = this.PenColor;
dColor.ScA = System.Convert.ToSingle(0.5);
this._inkCanvas.DefaultDrawingAttributes.Color = dColor;
} if (this._strokeType == StrokeType.EraseByPoint)
{
this._inkCanvas.EditingMode = InkCanvasEditingMode.EraseByPoint;
this._inkCanvas.DefaultDrawingAttributes.Width = this.EraseWidth;
this._inkCanvas.DefaultDrawingAttributes.Height = this.EraseWidth;
}
}
} public Brush Background
{
get { return this._inkCanvas.Background; }
set
{
this._inkCanvas.Background = value;
}
} protected override int VisualChildrenCount
{
get
{
return ; //grid + inkcanvas
}
} public MultiTouchCanvas(){
base.IsManipulationEnabled = true;
this.transparentOverlay.Background = Brushes.Transparent;
base.IsEnabled =true; this.InitInkCanvasPropertys();
this._inkCanvas.DefaultDrawingAttributes = new DrawingAttributes();
this._inkCanvas.DefaultDrawingAttributes.Color = Colors.Green;
this._inkCanvas.DefaultDrawingAttributes.Width = ;
this._inkCanvas.DefaultDrawingAttributes.Height = ; this.PenType = StrokeType.Stroke;
} public void ClearStrokes(object device)
{
if (this._strokes.ContainsKey(device) && this._inkCanvas.Strokes != null && this._inkCanvas.Strokes.Count > )
{
StrokeCollection sc = this._strokes[device];
this._inkCanvas.Strokes.Remove(sc);
this._strokes.Remove(device);
}
} public StrokeCollection GetStrokes(object device)
{
return this._strokes.ContainsKey(device) ? this._strokes[device] : null;
} #region Event handle
protected override void OnPreviewTouchDown(TouchEventArgs e)
{
TouchPoint tp = e.GetTouchPoint(this);
if (this._inkCanvas.EditingMode == InkCanvasEditingMode.Ink)
{
this._startStroke(e.Device, tp.Position);
}
else
{
if (this._inkCanvas.EditingMode == InkCanvasEditingMode.EraseByPoint)
{
this._removeStroke(e.Device, tp.Position);
}
} e.Handled = true;
base.Focusable = true;
base.Focus();
base.Focusable = false;
e.TouchDevice.Capture(this);
} protected override void OnPreviewTouchMove(TouchEventArgs e)
{
_handleTouchMove(e);
} protected override void OnTouchUp(TouchEventArgs e)
{
e.TouchDevice.Capture(null); //
} protected override void OnMouseDown(MouseButtonEventArgs e)
{
if (base.Visibility == System.Windows.Visibility.Visible)
{
if (this._inkCanvas.EditingMode == InkCanvasEditingMode.Ink)
{
this._startStroke(e.Device, e.GetPosition(this));
}
else
{
if (this._inkCanvas.EditingMode == InkCanvasEditingMode.EraseByPoint)
{
this._removeStroke(e.Device, e.GetPosition(this));
}
} e.MouseDevice.Capture(this);
}
} protected override void OnMouseMove(MouseEventArgs e)
{
if (e.LeftButton == MouseButtonState.Pressed)
{
if (this._inkCanvas.EditingMode == InkCanvasEditingMode.EraseByPoint)
{
this._removeStroke(e.Device, e.GetPosition(this));
return;
}
if (this._strokes.ContainsKey(e.Device) && this._currentStroke.ContainsKey(e.Device))
{
this._addPointToStroke(e.Device, e.GetPosition(this));
}
else
{
this._startStroke(e.Device, e.GetPosition(this));
}
}
} protected override void OnMouseUp(MouseButtonEventArgs e)
{
e.MouseDevice.Capture(null);
}
#endregion protected override Visual GetVisualChild(int index)
{
switch (index)
{
case : return this._inkCanvas;
case : return this.transparentOverlay;
default:
throw new ArgumentOutOfRangeException("index");
}
} protected override Size MeasureOverride(Size availableSize)
{
this._inkCanvas.Measure(availableSize);
this.transparentOverlay.Measure(availableSize);
return this._inkCanvas.DesiredSize;
} protected override Size ArrangeOverride(Size finalSize)
{
this._inkCanvas.Arrange(new Rect(finalSize));
this.transparentOverlay.Arrange(new Rect(finalSize));
return base.ArrangeOverride(finalSize); } protected override void OnInitialized(EventArgs e)
{
base.OnInitialized(e);
base.AddVisualChild(this._inkCanvas);
base.AddVisualChild(this.transparentOverlay);
}
private void _handleTouchMove(TouchEventArgs e)
{
if(this._inkCanvas.EditingMode == InkCanvasEditingMode.EraseByPoint){
this._removeStroke(e.Device , e.GetTouchPoint(this).Position);
e.Handled = true;
return ;
} if(this._strokes.ContainsKey(e.Device) && this._currentStroke.ContainsKey(e.Device))
{
Stroke stroke = this._currentStroke[e.Device];
StylusPointCollection sps = stroke.StylusPoints;
if(sps != null){
TouchPoint tp = e.GetTouchPoint(this);
Point p = tp.Position;
this._addPointToStroke( e.Device , p);
}
}
else
{
TouchPoint tp = e.GetTouchPoint(this);
this._startStroke( e.Device ,tp.Position);
}
e.Handled = true;
} private void _addPointToStroke(object device, Point position)
{
Stroke stroke = this._currentStroke[device];
if (stroke != null)
{
StylusPointCollection spc = stroke.StylusPoints;
if (spc != null)
{
spc.Add(new StylusPoint(position.X, position.Y, 0.5f));
}
}
} private void _removeStroke(object device, Point position)
{
for (int i = ; i < this._inkCanvas.Strokes.Count; i++)
{
Stroke stroke = this._inkCanvas.Strokes[i];
StrokeCollection sc = stroke.GetEraseResult(new Rect(position.X, position.Y, this._inkCanvas.DefaultDrawingAttributes.Width, this._inkCanvas.DefaultDrawingAttributes.Height));
this._inkCanvas.Strokes.Replace(stroke, sc);
}
} private void _startStroke(object device, Point inputPosition)
{
StylusPointCollection stylusPointCollection = new StylusPointCollection();
stylusPointCollection.Add(new StylusPoint(inputPosition.X, inputPosition.Y, 0.5f)); if (stylusPointCollection.Count > )
{
Stroke stroke = new Stroke(stylusPointCollection);
stroke.DrawingAttributes.Width = this._inkCanvas.DefaultDrawingAttributes.Width;
stroke.DrawingAttributes.Height = this._inkCanvas.DefaultDrawingAttributes.Height;
stroke.DrawingAttributes.Color = this._inkCanvas.DefaultDrawingAttributes.Color;
this._inkCanvas.Strokes.Add(stroke);//添加到canvas
if (this._currentStroke.ContainsKey(device))
{
this._currentStroke.Remove(device);
}
this._currentStroke.Add(device, stroke); if (this._strokes.ContainsKey(device))
{
this._strokes[device].Add(this._currentStroke[device]);
return;
} this._strokes.Add(device, new StrokeCollection { this._currentStroke[device] });
}
} private void InitInkCanvasPropertys(){
this._inkCanvas.Focusable = base.Focusable;
this._inkCanvas.Background = Brushes.Transparent;
this._inkCanvas.EditingMode = InkCanvasEditingMode.Ink;
this._inkCanvas.UseCustomCursor = true;
}
}
InkCanvasProxy和StrokeType的代码
public enum StrokeType
{
Stroke,
HighlighterStroke,
EraseByPoint
} public class InkCanvasProxy : InkCanvas
{
public InkCanvasProxy()
: base()
{
// base.IsHitTestVisible = false;
// base.StylusPlugIns.Remove(base.DynamicRenderer);
}
}
实例demo，调用: 新建一个WPF程序，然后在mainwindow.xaml添加
<Window x:Class="Metro.G.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="600" Width="600"
xmlns:ll="clr-namespace:Metro.G">
<Canvas Name="container" >
<ll:MultiTouchCanvas Width="600" Height="600" x:Name="_canvas"></ll:MultiTouchCanvas>
</Canvas>
</Window>
画笔的类型，颜色以及粗细通过MultiTouchCanvas的属性设置