「LEADTOOLS」を使ってWindowsストアアプリに画像処理機能を実装しよう

XAMLの定義

　XAMLエディタまたはBlendで定義するXAMLの内容は、次のようになります。

リスト1 MainPage.xaml

<Page
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:CZ1401ImagingVB"
    xmlns:common="using:CZ1401ImagingVB.Common"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:custom="using:Leadtools.Controls"
    xmlns:Converter="using:CZ1401ImagingVB.Converter"
    x:Name="pageRoot"
    x:Class="CZ1401ImagingVB.MainPage"
    mc:Ignorable="d">
 
    <Page.BottomAppBar>
        <CommandBar>
            <AppBarButton Label="画像指定" Icon="OpenFile" Command="{Binding OpenCommand}"/>
        </CommandBar>
    </Page.BottomAppBar>
 
    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <Grid.ChildrenTransitions>
            <TransitionCollection>
                <EntranceThemeTransition/>
            </TransitionCollection>
        </Grid.ChildrenTransitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="140"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
 
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="120"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <Button x:Name="backButton" Margin="39,59,39,0" 
                Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}"
                Style="{StaticResource NavigationBackButtonNormalStyle}"
                VerticalAlignment="Top"
                AutomationProperties.Name="Back"
                AutomationProperties.AutomationId="BackButton"
                AutomationProperties.ItemType="Navigation Button"/>
            <TextBlock x:Name="pageTitle" Text="{StaticResource AppName}" 
                Style="{StaticResource HeaderTextBlockStyle}" Grid.Column="1" 
                IsHitTestVisible="false" TextWrapping="NoWrap" 
                VerticalAlignment="Bottom" Margin="0,0,30,40"/>
        </Grid>
        <Grid Grid.Row="1">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="1*" />
                <ColumnDefinition Width="1*" />
            </Grid.ColumnDefinitions>
            <Image Grid.Column="0"
                   Stretch="None"
                   Source="{Binding ImageElement}"/>
            <custom:RasterImageViewer
                Grid.Column="1" 
                Image="{Binding RasterElement}"/>
        </Grid>
    </Grid>
</Page>

　LEADTOOLSのコンポーネントは、Imageプロパティに表示したい画像データをBindingしているだけで特に何もプロパティを指定していません。

LEADTOOLSでの読み込みロジックの記述（PictureModel）

リスト2 PictureModel.vb

Public Class PictureModel
    Implements INotifyPropertyChanged
 
    Private _ImageElement As ImageSource = Nothing
    Public Property ImageElement As ImageSource
        Get
            Return Me._ImageElement
        End Get
        Set(value As ImageSource)
            Me._ImageElement = value
            OnPropertyChanged()
        End Set
    End Property
 
    Private _RasterElement As Leadtools.RasterImage
    Public Property RasterElement As Leadtools.RasterImage              ' …①
        Get
            Return Me._RasterElement
        End Get
        Set(value As Leadtools.RasterImage)
            Me._RasterElement = value
            OnPropertyChanged()
        End Set
    End Property
 
    Public Async Function Open() As Task
        Dim picker = New Pickers.FileOpenPicker With {                  ' …②
            .ViewMode = Pickers.PickerViewMode.Thumbnail,
            .SuggestedStartLocation = Pickers.PickerLocationId.PicturesLibrary
        }
        picker.FileTypeFilter.Clear()
        picker.FileTypeFilter.Add(".jpg")
        picker.FileTypeFilter.Add(".png")
        picker.FileTypeFilter.Add(".tif")
        Dim file As StorageFile = Await picker.PickSingleFileAsync()    ' …③
        If file IsNot Nothing Then
            Using fileStream = Await file.OpenAsync(FileAccessMode.Read)
                Dim bitmap = New Windows.UI.Xaml.Media.Imaging.BitmapImage
                bitmap.SetSource(fileStream)
                Me.ImageElement = bitmap
            End Using
            Dim leadStream As Leadtools.ILeadStream = Leadtools.LeadStreamFactory.Create(file)
            Using disposable As IDisposable = TryCast(leadStream, IDisposable)
                Using codecs As New Leadtools.Codecs.RasterCodecs
                    Dim workImage = Await codecs.LoadAsync(leadStream)
                    Me.RasterElement = workImage                        ' …④
                End Using
            End Using
        End If
    End Function
 
    Public Event PropertyChanged(sender As Object,
                                 e As PropertyChangedEventArgs) _
                             Implements INotifyPropertyChanged.PropertyChanged
    Private Sub OnPropertyChanged(<CallerMemberName> Optional propertyName As String = Nothing)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
    End Sub
End Class

• ①LEADTOOLSのラスターイメージを格納するパブリックプロパティを定義
• ②画像ライブラリを開くためのFileOpenPickerを定義
• ③FileOpenPickerを実行
• ④指定された画像から作成したラスターイメージをパブリックプロパティに設定