How to: Select Ink from a Custom Control
By adding an IncrementalLassoHitTester to your custom control, you can enable your control so that a user can select ink with a lasso tool, similar to the way the InkCanvas selects ink with a lasso.
This example assumes you are familiar with creating an ink-enabled custom control. To create a custom control that accepts ink input, see Creating an Ink Input Control.
Example
When the user draws a lasso, the IncrementalLassoHitTester predicts which strokes will be within the lasso path's boundaries after the user completes the lasso. Strokes that are determined to be within the lasso path's boundaries can be thought of as being selected. Selected strokes can also become unselected. For example, if the user reverses direction while drawing the lasso, the IncrementalLassoHitTester may unselect some strokes.
The IncrementalLassoHitTester raises the SelectionChanged event, which enables your custom control to respond while the user is drawing the lasso. For example, you can change the appearance of strokes as the user selects and unselects them.
Managing the Ink Mode
It is helpful to the user if the lasso appears differently than the ink on your control. To accomplish this, your custom control must keep track of whether the user is writing or selecting ink. The easiest way to do this is to declare an enumeration with two values: one to indicate that the user is writing ink and one to indicate that the user is selecting ink.
' Enum that keeps track of whether StrokeCollectionDemo is in ink mode
' or select mode.
Public Enum InkMode
Ink
[Select]
End Enum 'InkMode
// Enum that keeps track of whether StrokeCollectionDemo is in ink mode
// or select mode.
public enum InkMode
{
Ink, Select
}
Next, add two DrawingAttributes to the class: one to use when the user writes ink, one to use when the user selects ink. In the constructor, initialize the DrawingAttributes and attach both AttributeChanged events to the same event handler. Then set the DrawingAttributes property of the DynamicRenderer to the ink DrawingAttributes.
Private inkDA As DrawingAttributes
Private selectDA As DrawingAttributes
...
' In the constructor.
' Selection drawing attributes use dark gray ink.
selectDA = New DrawingAttributes()
selectDA.Color = Colors.DarkGray
' ink drawing attributes use default attributes
inkDA = New DrawingAttributes()
inkDA.Width = 5
inkDA.Height = 5
AddHandler inkDA.AttributeChanged, _
AddressOf DrawingAttributesChanged
AddHandler selectDA.AttributeChanged, _
AddressOf DrawingAttributesChanged
DrawingAttributes inkDA;
DrawingAttributes selectDA;
...
// In the constructor.
// Selection drawing attributes use dark gray ink.
selectDA = new DrawingAttributes();
selectDA.Color = Colors.DarkGray;
// ink drawing attributes use default attributes
inkDA = new DrawingAttributes();
inkDA.Width = 5;
inkDA.Height = 5;
inkDA.AttributeChanged += new PropertyDataChangedEventHandler(DrawingAttributesChanged);
selectDA.AttributeChanged += new PropertyDataChangedEventHandler(DrawingAttributesChanged);
Add a property that exposes the selection mode. When the user changes the selection mode, set the DrawingAttributes property of the DynamicRenderer to the appropriate DrawingAttributes object and then reattach the RootVisual Property to the InkPresenter.
' Property to indicate whether the user is inputting or
' selecting ink.
Public Property Mode() As InkMode
Get
Return Mode
End Get
Set(ByVal value As InkMode)
modeState = value
' Set the DrawingAttributes of the DynamicRenderer
If modeState = InkMode.Ink Then
renderer.DrawingAttributes = inkDA
Else
renderer.DrawingAttributes = selectDA
End If
' Reattach the visual of the DynamicRenderer to the InkPresenter.
presenter.DetachVisuals(renderer.RootVisual)
presenter.AttachVisuals(renderer.RootVisual, renderer.DrawingAttributes)
End Set
End Property
// Property to indicate whether the user is inputting or
// selecting ink.
public InkMode Mode
{
get
{
return mode;
}
set
{
mode = value;
// Set the DrawingAttributes of the DynamicRenderer
if (mode == InkMode.Ink)
{
renderer.DrawingAttributes = inkDA;
}
else
{
renderer.DrawingAttributes = selectDA;
}
// Reattach the visual of the DynamicRenderer to the InkPresenter.
presenter.DetachVisuals(renderer.RootVisual);
presenter.AttachVisuals(renderer.RootVisual, renderer.DrawingAttributes);
}
}
Expose the DrawingAttributes as properties so applications can determine the appearance of the ink strokes and selection strokes.
' Property to allow the user to change the pen's DrawingAttributes.
Public ReadOnly Property InkDrawingAttributes() As DrawingAttributes
Get
Return inkDA
End Get
End Property
' Property to allow the user to change the Selector'newStroke DrawingAttributes.
Public ReadOnly Property SelectDrawingAttributes() As DrawingAttributes
Get
Return selectDA
End Get
End Property
// Property to allow the user to change the pen's DrawingAttributes.
public DrawingAttributes InkDrawingAttributes
{
get
{
return inkDA;
}
}
// Property to allow the user to change the Selector'newStroke DrawingAttributes.
public DrawingAttributes SelectDrawingAttributes
{
get
{
return selectDA;
}
}
When a property of a DrawingAttributes object changes, the RootVisual must be reattached to the InkPresenter. In the event handler for the AttributeChanged event, reattach the RootVisual to the InkPresenter.
Private Sub DrawingAttributesChanged(ByVal sender As Object, _
ByVal e As PropertyDataChangedEventArgs)
' Reattach the visual of the DynamicRenderer to the InkPresenter
' whenever the DrawingAttributes change.
presenter.DetachVisuals(renderer.RootVisual)
presenter.AttachVisuals(renderer.RootVisual, _
renderer.DrawingAttributes)
End Sub 'DrawingAttributesChanged
void DrawingAttributesChanged(object sender, PropertyDataChangedEventArgs e)
{
// Reattach the visual of the DynamicRenderer to the InkPresenter
// whenever the DrawingAttributes change.
presenter.DetachVisuals(renderer.RootVisual);
presenter.AttachVisuals(renderer.RootVisual, renderer.DrawingAttributes);
}
Using the IncrementalLassoHitTester
Create and initialize a StrokeCollection that contains the selected strokes.
' StylusPointCollection that collects the stylus points from the stylus events.
Private stylusPoints As StylusPointCollection
// StylusPointCollection that collects the stylus points from the stylus events.
StylusPointCollection stylusPoints;
When the user starts to draw a stroke, either ink or the lasso, unselect any selected strokes. Then, if the user is drawing a lasso, create an IncrementalLassoHitTester by calling GetIncrementalLassoHitTester, subscribe to the SelectionChanged event, and call AddPoints. This code can be a separate method and called from the OnStylusDown and OnMouseDown methods.
Private Sub InitializeHitTester(ByVal collectedPoints As StylusPointCollection)
' Deselect any selected strokes.
Dim selectedStroke As Stroke
For Each selectedStroke In selectedStrokes
selectedStroke.DrawingAttributes.Color = inkDA.Color
Next selectedStroke
selectedStrokes.Clear()
If modeState = InkMode.Select Then
' Remove the previously drawn lasso, if it exists.
If Not (lassoPath Is Nothing) Then
presenter.Strokes.Remove(lassoPath)
lassoPath = Nothing
End If
selectionTester = presenter.Strokes.GetIncrementalLassoHitTester(80)
AddHandler selectionTester.SelectionChanged, AddressOf selectionTester_SelectionChanged
selectionTester.AddPoints(collectedPoints)
End If
End Sub 'InitializeHitTester
private void InitializeHitTester(StylusPointCollection collectedPoints)
{
// Deselect any selected strokes.
foreach (Stroke selectedStroke in selectedStrokes)
{
selectedStroke.DrawingAttributes.Color = inkDA.Color;
}
selectedStrokes.Clear();
if (mode == InkMode.Select)
{
// Remove the previously drawn lasso, if it exists.
if (lassoPath != null)
{
presenter.Strokes.Remove(lassoPath);
lassoPath = null;
}
selectionTester =
presenter.Strokes.GetIncrementalLassoHitTester(80);
selectionTester.SelectionChanged +=
new LassoSelectionChangedEventHandler(selectionTester_SelectionChanged);
selectionTester.AddPoints(collectedPoints);
}
}
Add the stylus points to the IncrementalLassoHitTester while the user draws the lasso. Call the following method from the OnStylusMove, OnStylusUp, OnMouseMove, and OnMouseLeftButtonUp methods.
Private Sub AddPointsToHitTester(ByVal collectedPoints As StylusPointCollection)
If modeState = InkMode.Select AndAlso _
Not selectionTester Is Nothing AndAlso _
selectionTester.IsValid Then
' When the control is selecting strokes, add the
' stylus packetList to selectionTester.
selectionTester.AddPoints(collectedPoints)
End If
End Sub 'AddPointsToHitTester
private void AddPointsToHitTester(StylusPointCollection collectedPoints)
{
if (mode == InkMode.Select &&
selectionTester != null &&
selectionTester.IsValid)
{
// When the control is selecting strokes, add the
// stylus packetList to selectionTester.
selectionTester.AddPoints(collectedPoints);
}
}
Handle the IncrementalLassoHitTester.SelectionChanged event to respond when the user selects and unselects strokes. The LassoSelectionChangedEventArgs class has the SelectedStrokes and DeselectedStrokes properties that get the strokes that were selected and unselected, respectively.
Private Sub selectionTester_SelectionChanged(ByVal sender As Object, _
ByVal args As LassoSelectionChangedEventArgs)
' Change the color of all selected strokes to red.
Dim selectedStroke As Stroke
For Each selectedStroke In args.SelectedStrokes
selectedStroke.DrawingAttributes.Color = Colors.Red
selectedStrokes.Add(selectedStroke)
Next selectedStroke
' Change the color of all unselected strokes to
' their original color.
Dim unselectedStroke As Stroke
For Each unselectedStroke In args.DeselectedStrokes
unselectedStroke.DrawingAttributes.Color = inkDA.Color
selectedStrokes.Remove(unselectedStroke)
Next unselectedStroke
End Sub 'selectionTester_SelectionChanged
void selectionTester_SelectionChanged(object sender,
LassoSelectionChangedEventArgs args)
{
// Change the color of all selected strokes to red.
foreach (Stroke selectedStroke in args.SelectedStrokes)
{
selectedStroke.DrawingAttributes.Color = Colors.Red;
selectedStrokes.Add(selectedStroke);
}
// Change the color of all unselected strokes to
// their original color.
foreach (Stroke unselectedStroke in args.DeselectedStrokes)
{
unselectedStroke.DrawingAttributes.Color = inkDA.Color;
selectedStrokes.Remove(unselectedStroke);
}
}
When the user finishes drawing the lasso, unsubscribe from the SelectionChanged event and call EndHitTesting.
If modeState = InkMode.Select AndAlso lassoPath Is Nothing Then
' Add the lasso to the InkPresenter and add the packetList
' to selectionTester.
lassoPath = newStroke
lassoPath.DrawingAttributes = selectDA.Clone()
presenter.Strokes.Add(lassoPath)
RemoveHandler selectionTester.SelectionChanged, _
AddressOf selectionTester_SelectionChanged
selectionTester.EndHitTesting()
End If
if (mode == InkMode.Select && lassoPath == null)
{
// Add the lasso to the InkPresenter and add the packetList
// to selectionTester.
lassoPath = newStroke;
lassoPath.DrawingAttributes = selectDA.Clone();
presenter.Strokes.Add(lassoPath);
selectionTester.SelectionChanged -= new LassoSelectionChangedEventHandler
(selectionTester_SelectionChanged);
selectionTester.EndHitTesting();
}
Putting it All Together.
The following example is a custom control that enables a user to select ink with a lasso.
Imports System
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Input
Imports System.Windows.Input.StylusPlugIns
Imports System.Windows.Ink
' Enum that keeps track of whether StrokeCollectionDemo is in ink mode
' or select mode.
Public Enum InkMode
Ink
[Select]
End Enum 'InkMode
' This control allows the user to input and select ink. When the
' user selects ink, the lasso remains visible until they erase, or clip
' the selected strokes, or clear the selection. When the control is
' in selection mode, strokes that are selected turn red.
Public Class InkSelector
Inherits Label
Private modeState As InkMode
Private inkDA As DrawingAttributes
Private selectDA As DrawingAttributes
Private presenter As InkPresenter
Private selectionTester As IncrementalLassoHitTester
Private selectedStrokes As New StrokeCollection()
' StylusPointCollection that collects the stylus points from the stylus events.
Private stylusPoints As StylusPointCollection
' Stroke that represents the lasso.
Private lassoPath As Stroke
Private renderer As DynamicRenderer
Public Sub New()
modeState = InkMode.Ink
' Use an InkPresenter to display the strokes on the custom control.
presenter = New InkPresenter()
Me.Content = presenter
' In the constructor.
' Selection drawing attributes use dark gray ink.
selectDA = New DrawingAttributes()
selectDA.Color = Colors.DarkGray
' ink drawing attributes use default attributes
inkDA = New DrawingAttributes()
inkDA.Width = 5
inkDA.Height = 5
AddHandler inkDA.AttributeChanged, _
AddressOf DrawingAttributesChanged
AddHandler selectDA.AttributeChanged, _
AddressOf DrawingAttributesChanged
' Add a DynmaicRenderer to the control so ink appears
' to "flow" from the tablet pen.
renderer = New DynamicRenderer()
renderer.DrawingAttributes = inkDA
Me.StylusPlugIns.Add(renderer)
presenter.AttachVisuals(renderer.RootVisual, _
renderer.DrawingAttributes)
End Sub 'New
Shared Sub New()
' Allow ink to be drawn only within the bounds of the control.
Dim owner As Type = GetType(InkSelector)
ClipToBoundsProperty.OverrideMetadata(owner, _
New FrameworkPropertyMetadata(True))
End Sub 'New
' Prepare to collect stylus packets. If Mode is set to Select,
' get the IncrementalHitTester from the InkPresenter'newStroke
' StrokeCollection and subscribe to its StrokeHitChanged event.
Protected Overrides Sub OnStylusDown(ByVal e As StylusDownEventArgs)
MyBase.OnStylusDown(e)
Stylus.Capture(Me)
' Create a new StylusPointCollection using the StylusPointDescription
' from the stylus points in the StylusDownEventArgs.
stylusPoints = New StylusPointCollection()
Dim eventPoints As StylusPointCollection = e.GetStylusPoints(Me, stylusPoints.Description)
stylusPoints.Add(eventPoints)
InitializeHitTester(eventPoints)
End Sub 'OnStylusDown
Protected Overrides Sub OnMouseLeftButtonDown(ByVal e As MouseButtonEventArgs)
MyBase.OnMouseLeftButtonDown(e)
Mouse.Capture(Me)
If Not (e.StylusDevice Is Nothing) Then
Return
End If
Dim pt As Point = e.GetPosition(Me)
Dim collectedPoints As New StylusPointCollection(New Point() {pt})
stylusPoints = New StylusPointCollection()
stylusPoints.Add(collectedPoints)
InitializeHitTester(collectedPoints)
End Sub 'OnMouseLeftButtonDown
Private Sub InitializeHitTester(ByVal collectedPoints As StylusPointCollection)
' Deselect any selected strokes.
Dim selectedStroke As Stroke
For Each selectedStroke In selectedStrokes
selectedStroke.DrawingAttributes.Color = inkDA.Color
Next selectedStroke
selectedStrokes.Clear()
If modeState = InkMode.Select Then
' Remove the previously drawn lasso, if it exists.
If Not (lassoPath Is Nothing) Then
presenter.Strokes.Remove(lassoPath)
lassoPath = Nothing
End If
selectionTester = presenter.Strokes.GetIncrementalLassoHitTester(80)
AddHandler selectionTester.SelectionChanged, AddressOf selectionTester_SelectionChanged
selectionTester.AddPoints(collectedPoints)
End If
End Sub 'InitializeHitTester
' Collect the stylus packets as the stylus moves.
Protected Overrides Sub OnStylusMove(ByVal e As StylusEventArgs)
If stylusPoints Is Nothing Then
Return
End If
Dim collectedPoints As StylusPointCollection = e.GetStylusPoints(Me, stylusPoints.Description)
stylusPoints.Add(collectedPoints)
AddPointsToHitTester(collectedPoints)
End Sub 'OnStylusMove
Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)
MyBase.OnMouseMove(e)
If Not (e.StylusDevice Is Nothing) Then
Return
End If
If e.LeftButton = MouseButtonState.Released Then
Return
End If
If stylusPoints Is Nothing Then
stylusPoints = New StylusPointCollection()
End If
Dim pt As Point = e.GetPosition(Me)
Dim collectedPoints As New StylusPointCollection(New Point() {pt})
stylusPoints.Add(collectedPoints)
AddPointsToHitTester(collectedPoints)
End Sub 'OnMouseMove
Private Sub AddPointsToHitTester(ByVal collectedPoints As StylusPointCollection)
If modeState = InkMode.Select AndAlso _
Not selectionTester Is Nothing AndAlso _
selectionTester.IsValid Then
' When the control is selecting strokes, add the
' stylus packetList to selectionTester.
selectionTester.AddPoints(collectedPoints)
End If
End Sub 'AddPointsToHitTester
' When the user lifts the stylus, create a Stroke from the
' collected stylus points and add it to the InkPresenter.
' When the control is selecting strokes, add the
' point data to the IncrementalHitTester.
Protected Overrides Sub OnStylusUp(ByVal e As StylusEventArgs)
If stylusPoints Is Nothing Then
stylusPoints = New StylusPointCollection()
End If
Dim collectedPoints As StylusPointCollection = _
e.GetStylusPoints(Me, stylusPoints.Description)
stylusPoints.Add(collectedPoints)
AddPointsToHitTester(collectedPoints)
AddStrokeToPresenter()
stylusPoints = Nothing
Stylus.Capture(Nothing)
End Sub 'OnStylusUp
Protected Overrides Sub OnMouseLeftButtonUp(ByVal e As MouseButtonEventArgs)
MyBase.OnMouseLeftButtonUp(e)
If Not (e.StylusDevice Is Nothing) Then
Return
End If
If stylusPoints Is Nothing Then
stylusPoints = New StylusPointCollection()
End If
Dim pt As Point = e.GetPosition(Me)
Dim collectedPoints As New StylusPointCollection(New Point() {pt})
stylusPoints.Add(collectedPoints)
AddPointsToHitTester(collectedPoints)
AddStrokeToPresenter()
stylusPoints = Nothing
Mouse.Capture(Nothing)
End Sub 'OnMouseLeftButtonUp
Private Sub AddStrokeToPresenter()
Dim newStroke As New Stroke(stylusPoints)
If modeState = InkMode.Ink Then
' Add the stroke to the InkPresenter.
newStroke.DrawingAttributes = inkDA.Clone()
presenter.Strokes.Add(newStroke)
End If
If modeState = InkMode.Select AndAlso lassoPath Is Nothing Then
' Add the lasso to the InkPresenter and add the packetList
' to selectionTester.
lassoPath = newStroke
lassoPath.DrawingAttributes = selectDA.Clone()
presenter.Strokes.Add(lassoPath)
RemoveHandler selectionTester.SelectionChanged, _
AddressOf selectionTester_SelectionChanged
selectionTester.EndHitTesting()
End If
End Sub 'AddStrokeToPresenter
Private Sub selectionTester_SelectionChanged(ByVal sender As Object, _
ByVal args As LassoSelectionChangedEventArgs)
' Change the color of all selected strokes to red.
Dim selectedStroke As Stroke
For Each selectedStroke In args.SelectedStrokes
selectedStroke.DrawingAttributes.Color = Colors.Red
selectedStrokes.Add(selectedStroke)
Next selectedStroke
' Change the color of all unselected strokes to
' their original color.
Dim unselectedStroke As Stroke
For Each unselectedStroke In args.DeselectedStrokes
unselectedStroke.DrawingAttributes.Color = inkDA.Color
selectedStrokes.Remove(unselectedStroke)
Next unselectedStroke
End Sub 'selectionTester_SelectionChanged
' Property to indicate whether the user is inputting or
' selecting ink.
Public Property Mode() As InkMode
Get
Return Mode
End Get
Set(ByVal value As InkMode)
modeState = value
' Set the DrawingAttributes of the DynamicRenderer
If modeState = InkMode.Ink Then
renderer.DrawingAttributes = inkDA
Else
renderer.DrawingAttributes = selectDA
End If
' Reattach the visual of the DynamicRenderer to the InkPresenter.
presenter.DetachVisuals(renderer.RootVisual)
presenter.AttachVisuals(renderer.RootVisual, renderer.DrawingAttributes)
End Set
End Property
Private Sub DrawingAttributesChanged(ByVal sender As Object, _
ByVal e As PropertyDataChangedEventArgs)
' Reattach the visual of the DynamicRenderer to the InkPresenter
' whenever the DrawingAttributes change.
presenter.DetachVisuals(renderer.RootVisual)
presenter.AttachVisuals(renderer.RootVisual, _
renderer.DrawingAttributes)
End Sub 'DrawingAttributesChanged
' Property to allow the user to change the pen's DrawingAttributes.
Public ReadOnly Property InkDrawingAttributes() As DrawingAttributes
Get
Return inkDA
End Get
End Property
' Property to allow the user to change the Selector'newStroke DrawingAttributes.
Public ReadOnly Property SelectDrawingAttributes() As DrawingAttributes
Get
Return selectDA
End Get
End Property
End Class 'InkSelector
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Input;
using System.Windows.Input.StylusPlugIns;
using System.Windows.Ink;
// Enum that keeps track of whether StrokeCollectionDemo is in ink mode
// or select mode.
public enum InkMode
{
Ink, Select
}
// This control allows the user to input and select ink. When the
// user selects ink, the lasso remains visible until they erase, or clip
// the selected strokes, or clear the selection. When the control is
// in selection mode, strokes that are selected turn red.
public class InkSelector : Label
{
InkMode mode;
DrawingAttributes inkDA;
DrawingAttributes selectDA;
InkPresenter presenter;
IncrementalLassoHitTester selectionTester;
StrokeCollection selectedStrokes = new StrokeCollection();
// StylusPointCollection that collects the stylus points from the stylus events.
StylusPointCollection stylusPoints;
// Stroke that represents the lasso.
Stroke lassoPath;
DynamicRenderer renderer;
public InkSelector()
{
mode = InkMode.Ink;
// Use an InkPresenter to display the strokes on the custom control.
presenter = new InkPresenter();
this.Content = presenter;
// In the constructor.
// Selection drawing attributes use dark gray ink.
selectDA = new DrawingAttributes();
selectDA.Color = Colors.DarkGray;
// ink drawing attributes use default attributes
inkDA = new DrawingAttributes();
inkDA.Width = 5;
inkDA.Height = 5;
inkDA.AttributeChanged += new PropertyDataChangedEventHandler(DrawingAttributesChanged);
selectDA.AttributeChanged += new PropertyDataChangedEventHandler(DrawingAttributesChanged);
// Add a DynmaicRenderer to the control so ink appears
// to "flow" from the tablet pen.
renderer = new DynamicRenderer();
renderer.DrawingAttributes = inkDA;
this.StylusPlugIns.Add(renderer);
presenter.AttachVisuals(renderer.RootVisual,
renderer.DrawingAttributes);
}
static InkSelector()
{
// Allow ink to be drawn only within the bounds of the control.
Type owner = typeof(InkSelector);
ClipToBoundsProperty.OverrideMetadata(owner,
new FrameworkPropertyMetadata(true));
}
// Prepare to collect stylus packets. If Mode is set to Select,
// get the IncrementalHitTester from the InkPresenter'newStroke
// StrokeCollection and subscribe to its StrokeHitChanged event.
protected override void OnStylusDown(StylusDownEventArgs e)
{
base.OnStylusDown(e);
Stylus.Capture(this);
// Create a new StylusPointCollection using the StylusPointDescription
// from the stylus points in the StylusDownEventArgs.
stylusPoints = new StylusPointCollection();
StylusPointCollection eventPoints = e.GetStylusPoints(this, stylusPoints.Description);
stylusPoints.Add(eventPoints);
InitializeHitTester(eventPoints);
}
protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
{
base.OnMouseLeftButtonDown(e);
Mouse.Capture(this);
if (e.StylusDevice != null)
{
return;
}
Point pt = e.GetPosition(this);
StylusPointCollection collectedPoints = new StylusPointCollection(new Point[] { pt });
stylusPoints = new StylusPointCollection();
stylusPoints.Add(collectedPoints);
InitializeHitTester(collectedPoints);
}
private void InitializeHitTester(StylusPointCollection collectedPoints)
{
// Deselect any selected strokes.
foreach (Stroke selectedStroke in selectedStrokes)
{
selectedStroke.DrawingAttributes.Color = inkDA.Color;
}
selectedStrokes.Clear();
if (mode == InkMode.Select)
{
// Remove the previously drawn lasso, if it exists.
if (lassoPath != null)
{
presenter.Strokes.Remove(lassoPath);
lassoPath = null;
}
selectionTester =
presenter.Strokes.GetIncrementalLassoHitTester(80);
selectionTester.SelectionChanged +=
new LassoSelectionChangedEventHandler(selectionTester_SelectionChanged);
selectionTester.AddPoints(collectedPoints);
}
}
// Collect the stylus packets as the stylus moves.
protected override void OnStylusMove(StylusEventArgs e)
{
if (stylusPoints == null)
{
return;
}
StylusPointCollection collectedPoints = e.GetStylusPoints(this, stylusPoints.Description);
stylusPoints.Add(collectedPoints);
AddPointsToHitTester(collectedPoints);
}
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (e.StylusDevice != null)
{
return;
}
if (e.LeftButton == MouseButtonState.Released)
{
return;
}
if (stylusPoints == null)
{
stylusPoints = new StylusPointCollection();
}
Point pt = e.GetPosition(this);
StylusPointCollection collectedPoints = new StylusPointCollection(new Point[] { pt });
stylusPoints.Add(collectedPoints);
AddPointsToHitTester(collectedPoints);
}
private void AddPointsToHitTester(StylusPointCollection collectedPoints)
{
if (mode == InkMode.Select &&
selectionTester != null &&
selectionTester.IsValid)
{
// When the control is selecting strokes, add the
// stylus packetList to selectionTester.
selectionTester.AddPoints(collectedPoints);
}
}
// When the user lifts the stylus, create a Stroke from the
// collected stylus points and add it to the InkPresenter.
// When the control is selecting strokes, add the
// point data to the IncrementalHitTester.
protected override void OnStylusUp(StylusEventArgs e)
{
if (stylusPoints == null)
{
stylusPoints = new StylusPointCollection();
}
StylusPointCollection collectedPoints =
e.GetStylusPoints(this, stylusPoints.Description);
stylusPoints.Add(collectedPoints);
AddPointsToHitTester(collectedPoints);
AddStrokeToPresenter();
stylusPoints = null;
Stylus.Capture(null);
}
protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)
{
base.OnMouseLeftButtonUp(e);
if (e.StylusDevice != null) return;
if (stylusPoints == null) stylusPoints = new StylusPointCollection();
Point pt = e.GetPosition(this);
StylusPointCollection collectedPoints = new StylusPointCollection(new Point[] { pt });
stylusPoints.Add(collectedPoints);
AddPointsToHitTester(collectedPoints);
AddStrokeToPresenter();
stylusPoints = null;
Mouse.Capture(null);
}
private void AddStrokeToPresenter()
{
Stroke newStroke = new Stroke(stylusPoints);
if (mode == InkMode.Ink)
{
// Add the stroke to the InkPresenter.
newStroke.DrawingAttributes = inkDA.Clone();
presenter.Strokes.Add(newStroke);
}
if (mode == InkMode.Select && lassoPath == null)
{
// Add the lasso to the InkPresenter and add the packetList
// to selectionTester.
lassoPath = newStroke;
lassoPath.DrawingAttributes = selectDA.Clone();
presenter.Strokes.Add(lassoPath);
selectionTester.SelectionChanged -= new LassoSelectionChangedEventHandler
(selectionTester_SelectionChanged);
selectionTester.EndHitTesting();
}
}
void selectionTester_SelectionChanged(object sender,
LassoSelectionChangedEventArgs args)
{
// Change the color of all selected strokes to red.
foreach (Stroke selectedStroke in args.SelectedStrokes)
{
selectedStroke.DrawingAttributes.Color = Colors.Red;
selectedStrokes.Add(selectedStroke);
}
// Change the color of all unselected strokes to
// their original color.
foreach (Stroke unselectedStroke in args.DeselectedStrokes)
{
unselectedStroke.DrawingAttributes.Color = inkDA.Color;
selectedStrokes.Remove(unselectedStroke);
}
}
// Property to indicate whether the user is inputting or
// selecting ink.
public InkMode Mode
{
get
{
return mode;
}
set
{
mode = value;
// Set the DrawingAttributes of the DynamicRenderer
if (mode == InkMode.Ink)
{
renderer.DrawingAttributes = inkDA;
}
else
{
renderer.DrawingAttributes = selectDA;
}
// Reattach the visual of the DynamicRenderer to the InkPresenter.
presenter.DetachVisuals(renderer.RootVisual);
presenter.AttachVisuals(renderer.RootVisual, renderer.DrawingAttributes);
}
}
void DrawingAttributesChanged(object sender, PropertyDataChangedEventArgs e)
{
// Reattach the visual of the DynamicRenderer to the InkPresenter
// whenever the DrawingAttributes change.
presenter.DetachVisuals(renderer.RootVisual);
presenter.AttachVisuals(renderer.RootVisual, renderer.DrawingAttributes);
}
// Property to allow the user to change the pen's DrawingAttributes.
public DrawingAttributes InkDrawingAttributes
{
get
{
return inkDA;
}
}
// Property to allow the user to change the Selector'newStroke DrawingAttributes.
public DrawingAttributes SelectDrawingAttributes
{
get
{
return selectDA;
}
}
}