Практическое руководство. Выбор рукописного ввода из пользовательского элемента управления
Обновлен: Ноябрь 2007
Добавляя IncrementalLassoHitTester в пользовательский элементу управления, можно включить элемент управления, так что пользователь сможет выбрать рукописные данные с помощью инструмента лассо так же, как InkCanvas выделяет рукописные данные с помощью лассо.
В этом примере требуется знакомство с процессом создания пользовательского элемента управления, поддерживающего рукописный ввод. О создании пользовательского элемента управления, который принимает рукописный ввод, см. в разделе Создание элемента управления рукописным вводом.
Пример
Когда пользователь рисует лассо, IncrementalLassoHitTester прогнозирует какие штрихи будут в пределах границы контура лассо после того, как пользователь завершит лассо. Штрихи, которые находятся в пределах границы контура лассо, могут быть рассмотрены как выбранные. С выбранных штрихов также можно снять выделение. Например, если пользователь изменяет направление во время рисования лассо, IncrementalLassoHitTester может снять выделение некоторых штрихов.
IncrementalLassoHitTester вызывает событие SelectionChanged, которое включает реагирование пользовательского элемента управления, пока пользователь рисует лассо. Например, можно изменить внешний вид штрихов, когда пользователь выделяет и снимает выделение с них.
Управление режимом рукописного ввода
Для пользователей удобнее, если лассо отображается иначе, чем рукописные данные элемента управления. Чтобы выполнить это, пользовательский элемент управления должен следить за тем, пишет ли пользователь или выбирает рукописный ввод. Простейший способ сделать это состоит в том, чтобы объявить перечисление с двумя значениями, одно будет указывать, что пользователь записывает рукописные данные, а второе ― что пользователь выделяет их.
' 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
}
Далее, добавить два DrawingAttributes в класс: один для использования при записи пользователем рукописного ввода, другой ― при выборе пользователем рукописного ввода. В конструкторе инициализируйте DrawingAttributes и присоедините оба события AttributeChanged к одному и тому же обработчику событий. Затем установите свойство DrawingAttributesDynamicRenderer в атрибут рукописного ввода 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);
Добавьте свойство, которое предоставляет режим выделения. Когда пользователь изменяет режим выделения, установите свойство DrawingAttributesDynamicRenderer в соответствующий объект DrawingAttributes, и затем повторно присоедините свойство RootVisual к 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);
}
}
Предоставьте DrawingAttributes в качестве свойств, чтобы приложения могли определить внешний вид рукописных штрихов и штрихов выделенного фрагмента.
' 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;
}
}
Когда свойство объекта DrawingAttributes изменяется, RootVisual должен быть повторно присоединен к InkPresenter. В обработчике событий для события AttributeChanged повторно присоедините RootVisual к 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);
}
Использование IncrementalLassoHitTester
Создайте и инициализируйте StrokeCollection, содержащую выбранные штрихи.
' 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;
Когда пользователь начинает рисовать штрих, рукописный текст или лассо, снимите выделение со всех выделенных штрихов. Затем, если пользователь рисует лассо, создайте IncrementalLassoHitTesterс помощью вызова GetIncrementalLassoHitTester, подпишитесь на событие SelectionChanged и вызовите AddPoints. Этот код может быть отдельным методом и вызваться из методов OnStylusDown и OnMouseDown.
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);
}
}
Добавляйте точки пера к IncrementalLassoHitTester, пока пользователь рисует лассо. Вызовите следующий метод у методов OnStylusMove, OnStylusUpOnMouseMove и OnMouseLeftButtonUp.
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);
}
}
Обработайте событие IncrementalLassoHitTester.SelectionChanged для реагирования на то, когда пользователь выделяет и снимает выделение с штрихов. Класс LassoSelectionChangedEventArgs имеет SelectedStrokes и DeselectedStrokes свойства, получающие штрихи, которые были выделены и сняты с выделения, соответственно.
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);
}
}
Когда пользователь завершает рисование лассо, откажитесь от подписки события SelectionChanged и вызовите 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();
}
Объединение частей приложения
Следующий пример представляет пользовательский элемент управления, дающий пользователю возможность выбрать рукописный ввод с помощью лассо.
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;
}
}
}
См. также
Основные понятия
Создание элемента управления рукописным вводом