如何将Map中显示的图形转化成栅格文件

本例要实现的是如何将当前激活的Map中显示的图形转化成栅格文件。

l   要点

通过IMap实例获得IActiveView接口对象，定义IExporter接口变量，使用TiffExporter实现该接口并对其中的属性进行赋值，使用IActiveView.Output方法将Map中显示的图形导出。

主要用到IActiveView接口，IExporter接口和IEnvelope接口。

l   程序说明

函数Output将当前激活的Map中显示的图形转化成栅格文件，栅格文件路径及名称由参数sFileAllName确定。

l   代码

Private Sub Output(ByVal sFileAllName As String)

    Dim pMxDocument             As IMxDocument

    Dim pActiveView             As IActiveView

    Dim pExporter               As IExporter

    Dim pEnvelope               As IEnvelope

    Dim ptagRECT                As tagRECT

    Dim pTrackCancel            As ITrackCancel

    Dim lscreenResolution       As Long   

On Error GoTo ErrorHandler:

    Set pMxDocument = ThisDocument

    Set pActiveView = pMxDocument.ActiveView

    lscreenResolution = pActiveView.ScreenDisplay.DisplayTransformation.Resolution

    ptagRECT.Top = 0

    ptagRECT.Left = 0

    ptagRECT.Right = pActiveView.Extent.Width

    ptagRECT.bottom = pActiveView.Extent.Height

    'We must calculate the size of the user specified Rectangle in Device units

    'Hence convert width and height

    Set pEnvelope = New Envelope

    pEnvelope.PutCoords ptagRECT.Left, ptagRECT.bottom, ptagRECT.Right, ptagRECT.Top

    Set pExporter = New TiffExporter

    pExporter.Resolution = lscreenResolution

    pExporter.ExportFileName = sFileAllName

    pExporter.PixelBounds = pEnvelope

    Set pTrackCancel = New CancelTracker

    pActiveView.Output pExporter.StartExporting, lscreenResolution, _

                        ptagRECT, pActiveView.Extent, pTrackCancel

                       

    pExporter.FinishExporting

    Exit Sub

ErrorHandler:

    MsgBox Err.Description

End Sub

Private Sub UIButtonControl1_Click()

    Dim pVBProject              As VBProject

On Error GoTo ErrorHandler:

    Set pVBProject = ThisDocument.VBProject

    Output pVBProject.FileName & "\..\..\..\.." & "\data\MyTifFile.tif"

    Exit Sub

ErrorHandler:

    MsgBox Err.Description

End Sub