Cómo capturar e imprimir la pantalla, un formulario o cualquier ventana

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Resumen

En este artículo se muestra cómo capturar un formulario o ventana que incluya la pantalla en un objeto Picture de Visual Basic. Una vez capturada la imagen de la pantalla en el objeto Picture, se puede imprimir con facilidad utilizando el método PaintPicture del objeto Printer de Visual Basic.

Más información

El ejemplo incluido proporciona varias rutinas útiles para capturar las imágenes. Todas las rutinas se han escrito de modo que funcionen en plataformas de Windows de 16 y de 32 bits, y admiten todas las paletas. Las rutinas del ejemplo pueden:
  • Capturar todo el contenido de un formulario.
  • Capturar el área cliente de un formulario.
  • Capturar la pantalla completa.
  • Capturar la ventana activa en la pantalla.
  • Capturar un fragmento de una ventana dado su identificador.
  • Crear un objeto Picture a partir de un mapa de bits y una paleta.
  • Imprimir un objeto Picture tan grande como quepa en la página.
Visual Basic 4.0 introdujo un nuevo objeto Picture. El objeto Picture realmente es un tipo OLE estándar y se documenta en el Kit del programador de controles (CDK, Control Developer's Kit).

El CDK incluye la función OleCreatePictureIndirect, que se puede usar para crear nuevos objetos Picture en Visual Basic 4.0. La rutina CreateBitmapPicture del ejemplo llama a OleCreatePictureIndirect para generar un objeto Picture a partir de un identificador de un mapa de bits y de un identificador de una paleta. Si el objeto Picture incluye una paleta válida, Visual Basic sabrá usarla al representarlo en la pantalla o impresora. La rutina CaptureWindow utiliza la rutina CreateBitmapPicture para construir objetos Picture que contienen un mapa de bits de una parte de una ventana o de toda la ventana.

La rutina CaptureWindow del ejemplo captura una parte de una ventana dado un identificador de ventana. La rutina incluye varios parámetros para describir la parte exacta de la ventana que se va a capturar. Para capturar la ventana, se copia su imagen en la pantalla en un nuevo mapa de bits. También se comprueba si la pantalla tiene una paleta y, en ese caso, se realiza una copia de la misma. CaptureWindow llama a continuación a CreateBitmapPicture para construir un mapa de bits de la paleta y del mapa de bits recién creado.

Las rutinas CaptureForm, CaptureClient, CaptureScreen y CaptureActiveWindow incluidas en el ejemplo usan todas CaptureWindow para capturar ventanas concretas. CaptureForm y CaptureClient llaman ambos a CaptureWindow y le pasan la propiedad hWnd de un objeto Form. CaptureScreen simplemente obtiene el identificador de la ventana de la parte superior del escritorio y llama a CaptureWindow. De igual forma, CaptureActiveWindow sólo obtiene el identificador de la ventana activa y llama a CaptureWindow.

Una vez capturada en un objeto Picture la imagen deseada, es fácil imprimir en Visual Basic 4.0 utilizando el método PaintPicture del objeto Printer. El ejemplo proporciona la rutina PrintPictureToFitPage que utiliza PaintPictureMethod para imprimir las imágenes capturadas tan grandes como quepan en el área imprimible de la página.

Ejemplo

  1. Inicie un nuevo proyecto. De forma predeterminada, se crea Form1.
  2. Coloque seis CommandButtons en el formulario en el lado izquierdo.
  3. Coloque un cuadro de imagen en el formulario a la derecha de los botones.
  4. Ponga el código siguiente en Form1:
          '--------------------------------------------------------------------
          ' Capture the entire screen.
    
          Private Sub Command1_Click()
             Set Picture1.Picture = CaptureScreen()
          End Sub
    
          ' Capture the entire form including title and border.
          Private Sub Command2_Click()
             Set Picture1.Picture = CaptureForm(Me)
          End Sub
    
          ' Capture the client area of the form.
          Private Sub Command3_Click()
             Set Picture1.Picture = CaptureClient(Me)
          End Sub
    
          ' Capture the active window after two seconds.
          Private Sub Command4_Click()
             MsgBox "Two seconds after you close this dialog " & _
                "the active window will be captured."
    
             ' Wait for two seconds.
             Dim EndTime As Date
             EndTime = DateAdd("s", 2, Now)
             Do Until Now > EndTime
                DoEvents
             Loop
    
             Set Picture1.Picture = CaptureActiveWindow()
    
             ' Set focus back to form.
             Me.SetFocus
          End Sub
    
          ' Print the current contents of the picture box.
          Private Sub Command5_Click()
             PrintPictureToFitPage Printer, Picture1.Picture
             Printer.EndDoc
          End Sub
    
          ' Clear out the picture box.
          Private Sub Command6_Click()
             Set Picture1.Picture = Nothing
          End Sub
    
          ' Initialize the form and controls.
          Private Sub Form_Load()
             Me.Caption = "Capture and Print Example"
             Command1.Caption = "&Screen"
             Command2.Caption = "&Form"
             Command3.Caption = "&Client"
             Command4.Caption = "&Active"
             Command5.Caption = "&Print"
             Command6.Caption = "C&lear"
             Picture1.AutoSize = True
          End Sub
          '--------------------------------------------------------------------
    
    					
  5. Agregue un nuevo módulo estándar al proyecto (module1, de forma predeterminada).
  6. Ponga el siguiente código en el nuevo módulo:
          '--------------------------------------------------------------------
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' Visual Basic 4.0 16/32 Capture Routines
          '
          ' This module contains several routines for capturing windows into a
          ' picture.  All the routines work on both 16 and 32 bit Windows
          ' platforms.
          ' The routines also have palette support.
          '
          ' CreateBitmapPicture - Creates a picture object from a bitmap and
          ' palette.
          ' CaptureWindow - Captures any window given a window handle.
          ' CaptureActiveWindow - Captures the active window on the desktop.
          ' CaptureForm - Captures the entire form.
          ' CaptureClient - Captures the client area of a form.
          ' CaptureScreen - Captures the entire screen.
          ' PrintPictureToFitPage - prints any picture as big as possible on
          ' the page.
          '
          ' NOTES
          '    - No error trapping is included in these routines.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          Option Explicit
          Option Base 0
    
          Private Type PALETTEENTRY
             peRed As Byte
             peGreen As Byte
             peBlue As Byte
             peFlags As Byte
          End Type
    
          Private Type LOGPALETTE
             palVersion As Integer
             palNumEntries As Integer
             palPalEntry(255) As PALETTEENTRY  ' Enough for 256 colors.
          End Type
    
          Private Type GUID
             Data1 As Long
             Data2 As Integer
             Data3 As Integer
             Data4(7) As Byte
          End Type
    
          #If Win32 Then
    
             Private Const RASTERCAPS As Long = 38
             Private Const RC_PALETTE As Long = &H100
             Private Const SIZEPALETTE As Long = 104
    
             Private Type RECT
                Left As Long
                Top As Long
                Right As Long
                Bottom As Long
             End Type
    
             Private Declare Function CreateCompatibleDC Lib "GDI32" ( _
                ByVal hDC As Long) As Long
             Private Declare Function CreateCompatibleBitmap Lib "GDI32" ( _
                ByVal hDC As Long, ByVal nWidth As Long, _
                ByVal nHeight As Long) As Long
             Private Declare Function GetDeviceCaps Lib "GDI32" ( _
                ByVal hDC As Long, ByVal iCapabilitiy As Long) As Long
             Private Declare Function GetSystemPaletteEntries Lib "GDI32" ( _
                ByVal hDC As Long, ByVal wStartIndex As Long, _
                ByVal wNumEntries As Long, lpPaletteEntries As PALETTEENTRY) _
                As Long
             Private Declare Function CreatePalette Lib "GDI32" ( _
                lpLogPalette As LOGPALETTE) As Long
             Private Declare Function SelectObject Lib "GDI32" ( _
                ByVal hDC As Long, ByVal hObject As Long) As Long
             Private Declare Function BitBlt Lib "GDI32" ( _
                ByVal hDCDest As Long, ByVal XDest As Long, _
                ByVal YDest As Long, ByVal nWidth As Long, _
                ByVal nHeight As Long, ByVal hDCSrc As Long, _
                ByVal XSrc As Long, ByVal YSrc As Long, ByVal dwRop As Long) _
                As Long
             Private Declare Function DeleteDC Lib "GDI32" ( _
                ByVal hDC As Long) As Long
             Private Declare Function GetForegroundWindow Lib "USER32" () _
                As Long
             Private Declare Function SelectPalette Lib "GDI32" ( _
                ByVal hDC As Long, ByVal hPalette As Long, _
                ByVal bForceBackground As Long) As Long
             Private Declare Function RealizePalette Lib "GDI32" ( _
                ByVal hDC As Long) As Long
             Private Declare Function GetWindowDC Lib "USER32" ( _
                ByVal hWnd As Long) As Long
             Private Declare Function GetDC Lib "USER32" ( _
                ByVal hWnd As Long) As Long
             Private Declare Function GetWindowRect Lib "USER32" ( _
                ByVal hWnd As Long, lpRect As RECT) As Long
             Private Declare Function ReleaseDC Lib "USER32" ( _
                ByVal hWnd As Long, ByVal hDC As Long) As Long
             Private Declare Function GetDesktopWindow Lib "USER32" () As Long
    
             Private Type PicBmp
                Size As Long
                Type As Long
                hBmp As Long
                hPal As Long
                Reserved As Long
             End Type
    
             Private Declare Function OleCreatePictureIndirect _
                Lib "olepro32.dll" ( PicDesc As PicBmp, RefIID As GUID, _
                ByVal fPictureOwnsHandle As Long, IPic As IPicture) As Long
    
          #ElseIf Win16 Then
    
             Private Const RASTERCAPS As Integer = 38
             Private Const RC_PALETTE As Integer = &H100
             Private Const SIZEPALETTE As Integer = 104
    
             Private Type RECT
                Left As Integer
                Top As Integer
                Right As Integer
                Bottom As Integer
             End Type
    
             Private Declare Function CreateCompatibleDC Lib "GDI" ( _
                ByVal hDC As Integer) As Integer
             Private Declare Function CreateCompatibleBitmap Lib "GDI" ( _
                ByVal hDC As Integer, ByVal nWidth As Integer, _
                ByVal nHeight As Integer) As Integer
             Private Declare Function GetDeviceCaps Lib "GDI" ( _
                ByVal hDC As Integer, ByVal iCapabilitiy As Integer) As Integer
             Private Declare Function GetSystemPaletteEntries Lib "GDI" ( _
                ByVal hDC As Integer, ByVal wStartIndex As Integer, _
                ByVal wNumEntries As Integer, _
                lpPaletteEntries As PALETTEENTRY) As Integer
             Private Declare Function CreatePalette Lib "GDI" ( _
                lpLogPalette As LOGPALETTE) As Integer
             Private Declare Function SelectObject Lib "GDI" ( _
                ByVal hDC As Integer, ByVal hObject As Integer) As Integer
             Private Declare Function BitBlt Lib "GDI" ( _
                ByVal hDCDest As Integer, ByVal XDest As Integer, _
                ByVal YDest As Integer, ByVal nWidth As Integer, _
                ByVal nHeight As Integer, ByVal hDCSrc As Integer, _
                ByVal XSrc As Integer, ByVal YSrc As Integer, _
                ByVal dwRop As Long) As Integer
             Private Declare Function DeleteDC Lib "GDI" ( _
                ByVal hDC As Integer) As Integer
             Private Declare Function GetForegroundWindow Lib "USER" _
                Alias "GetActiveWindow" () As Integer
             Private Declare Function SelectPalette Lib "USER" ( _
                ByVal hDC As Integer, ByVal hPalette As Integer, ByVal _
                bForceBackground As Integer) As Integer
             Private Declare Function RealizePalette Lib "USER" ( _
                ByVal hDC As Integer) As Integer
             Private Declare Function GetWindowDC Lib "USER" ( _
                ByVal hWnd As Integer) As Integer
             Private Declare Function GetDC Lib "USER" ( _
                ByVal hWnd As Integer) As Integer
             Private Declare Function GetWindowRect Lib "USER" ( _
                ByVal hWnd As Integer, lpRect As RECT) As Integer
             Private Declare Function ReleaseDC Lib "USER" ( _
                ByVal hWnd As Integer, ByVal hDC As Integer) As Integer
             Private Declare Function GetDesktopWindow Lib "USER" () As Integer
    
             Private Type PicBmp
                Size As Integer
                Type As Integer
                hBmp As Integer
                hPal As Integer
                Reserved As Integer
             End Type
    
             Private Declare Function OleCreatePictureIndirect _
                Lib "oc25.dll" ( PictDesc As PicBmp, RefIID As GUID, _
                ByVal fPictureOwnsHandle As Integer, IPic As IPicture) _
                As Integer
    
          #End If
    
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' CreateBitmapPicture
          '    - Creates a bitmap type Picture object from a bitmap and
          '      palette.
          '
          ' hBmp
          '    - Handle to a bitmap.
          '
          ' hPal
          '    - Handle to a Palette.
          '    - Can be null if the bitmap doesn't use a palette.
          '
          ' Returns
          '    - Returns a Picture object containing the bitmap.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          #If Win32 Then
             Public Function CreateBitmapPicture(ByVal hBmp As Long, _
                ByVal hPal As Long) As Picture
    
                Dim r As Long
          #ElseIf Win16 Then
             Public Function CreateBitmapPicture(ByVal hBmp As Integer, _
                ByVal hPal As Integer) As Picture
    
                Dim r As Integer
          #End If
             Dim Pic As PicBmp
             ' IPicture requires a reference to "Standard OLE Types."
             Dim IPic As IPicture
             Dim IID_IDispatch As GUID
    
             ' Fill in with IDispatch Interface ID.
             With IID_IDispatch
                .Data1 = &H20400
                .Data4(0) = &HC0
                .Data4(7) = &H46
             End With
    
             ' Fill Pic with necessary parts.
             With Pic
                .Size = Len(Pic)          ' Length of structure.
                .Type = vbPicTypeBitmap   ' Type of Picture (bitmap).
                .hBmp = hBmp              ' Handle to bitmap.
                .hPal = hPal              ' Handle to palette (may be null).
             End With
    
             ' Create Picture object.
             r = OleCreatePictureIndirect(Pic, IID_IDispatch, 1, IPic)
    
             ' Return the new Picture object.
             Set CreateBitmapPicture = IPic
          End Function
    
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' CaptureWindow
          '    - Captures any portion of a window.
          '
          ' hWndSrc
          '    - Handle to the window to be captured.
          '
          ' Client
          '    - If True CaptureWindow captures from the client area of the
          '      window.
          '    - If False CaptureWindow captures from the entire window.
          '
          ' LeftSrc, TopSrc, WidthSrc, HeightSrc
          '    - Specify the portion of the window to capture.
          '    - Dimensions need to be specified in pixels.
          '
          ' Returns
          '    - Returns a Picture object containing a bitmap of the specified
          '      portion of the window that was captured.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          ''''''
          '
          #If Win32 Then
             Public Function CaptureWindow(ByVal hWndSrc As Long, _
                ByVal Client As Boolean, ByVal LeftSrc As Long, _
                ByVal TopSrc As Long, ByVal WidthSrc As Long, _
                ByVal HeightSrc As Long) As Picture
    
                Dim hDCMemory As Long
                Dim hBmp As Long
                Dim hBmpPrev As Long
                Dim r As Long
                Dim hDCSrc As Long
                Dim hPal As Long
                Dim hPalPrev As Long
                Dim RasterCapsScrn As Long
                Dim HasPaletteScrn As Long
                Dim PaletteSizeScrn As Long
          #ElseIf Win16 Then
             Public Function CaptureWindow(ByVal hWndSrc As Integer, _
                ByVal Client As Boolean, ByVal LeftSrc As Integer, _
                ByVal TopSrc As Integer, ByVal WidthSrc As Long, _
                ByVal HeightSrc As Long) As Picture
    
                Dim hDCMemory As Integer
                Dim hBmp As Integer
                Dim hBmpPrev As Integer
                Dim r As Integer
                Dim hDCSrc As Integer
                Dim hPal As Integer
                Dim hPalPrev As Integer
                Dim RasterCapsScrn As Integer
                Dim HasPaletteScrn As Integer
                Dim PaletteSizeScrn As Integer
          #End If
             Dim LogPal As LOGPALETTE
    
             ' Depending on the value of Client get the proper device context.
             If Client Then
                hDCSrc = GetDC(hWndSrc) ' Get device context for client area.
             Else
                hDCSrc = GetWindowDC(hWndSrc) ' Get device context for entire
                                              ' window.
             End If
    
             ' Create a memory device context for the copy process.
             hDCMemory = CreateCompatibleDC(hDCSrc)
             ' Create a bitmap and place it in the memory DC.
             hBmp = CreateCompatibleBitmap(hDCSrc, WidthSrc, HeightSrc)
             hBmpPrev = SelectObject(hDCMemory, hBmp)
    
             ' Get screen properties.
             RasterCapsScrn = GetDeviceCaps(hDCSrc, RASTERCAPS) ' Raster
                                                                ' capabilities.
             HasPaletteScrn = RasterCapsScrn And RC_PALETTE       ' Palette
                                                                  ' support.
             PaletteSizeScrn = GetDeviceCaps(hDCSrc, SIZEPALETTE) ' Size of
                                                                  ' palette.
    
             ' If the screen has a palette make a copy and realize it.
             If HasPaletteScrn And (PaletteSizeScrn = 256) Then
                ' Create a copy of the system palette.
                LogPal.palVersion = &H300
                LogPal.palNumEntries = 256
                r = GetSystemPaletteEntries(hDCSrc, 0, 256, _
                    LogPal.palPalEntry(0))
                hPal = CreatePalette(LogPal)
                ' Select the new palette into the memory DC and realize it.
                hPalPrev = SelectPalette(hDCMemory, hPal, 0)
                r = RealizePalette(hDCMemory)
             End If
    
             ' Copy the on-screen image into the memory DC.
             r = BitBlt(hDCMemory, 0, 0, WidthSrc, HeightSrc, hDCSrc, _
                LeftSrc, TopSrc, vbSrcCopy)
    
          ' Remove the new copy of the  on-screen image.
             hBmp = SelectObject(hDCMemory, hBmpPrev)
    
             ' If the screen has a palette get back the palette that was
             ' selected in previously.
             If HasPaletteScrn And (PaletteSizeScrn = 256) Then
                hPal = SelectPalette(hDCMemory, hPalPrev, 0)
             End If
    
             ' Release the device context resources back to the system.
             r = DeleteDC(hDCMemory)
             r = ReleaseDC(hWndSrc, hDCSrc)
    
             ' Call CreateBitmapPicture to create a picture object from the
             ' bitmap and palette handles. Then return the resulting picture
             ' object.
             Set CaptureWindow = CreateBitmapPicture(hBmp, hPal)
          End Function
    
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' CaptureScreen
          '    - Captures the entire screen.
          '
          ' Returns
          '    - Returns a Picture object containing a bitmap of the screen.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          Public Function CaptureScreen() As Picture
             #If Win32 Then
                Dim hWndScreen As Long
             #ElseIf Win16 Then
                Dim hWndScreen As Integer
             #End If
    
             ' Get a handle to the desktop window.
             hWndScreen = GetDesktopWindow()
    
             ' Call CaptureWindow to capture the entire desktop give the handle
             ' and return the resulting Picture object.
    
             Set CaptureScreen = CaptureWindow(hWndScreen, False, 0, 0, _
                Screen.Width \ Screen.TwipsPerPixelX, _
                Screen.Height \ Screen.TwipsPerPixelY)
          End Function
    
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' CaptureForm
          '    - Captures an entire form including title bar and border.
          '
          ' frmSrc
          '    - The Form object to capture.
          '
          ' Returns
          '    - Returns a Picture object containing a bitmap of the entire
          '      form.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          Public Function CaptureForm(frmSrc As Form) As Picture
             ' Call CaptureWindow to capture the entire form given its window
             ' handle and then return the resulting Picture object.
             Set CaptureForm = CaptureWindow(frmSrc.hWnd, False, 0, 0, _
                frmSrc.ScaleX(frmSrc.Width, vbTwips, vbPixels), _
                frmSrc.ScaleY(frmSrc.Height, vbTwips, vbPixels))
          End Function
    
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' CaptureClient
          '    - Captures the client area of a form.
          '
          ' frmSrc
          '    - The Form object to capture.
          '
          ' Returns
          '    - Returns a Picture object containing a bitmap of the form's
          '      client area.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          Public Function CaptureClient(frmSrc As Form) As Picture
             ' Call CaptureWindow to capture the client area of the form given
             ' its window handle and return the resulting Picture object.
             Set CaptureClient = CaptureWindow(frmSrc.hWnd, True, 0, 0, _
                frmSrc.ScaleX(frmSrc.ScaleWidth, frmSrc.ScaleMode, vbPixels), _
                frmSrc.ScaleY(frmSrc.ScaleHeight, frmSrc.ScaleMode, vbPixels))
          End Function
    
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' CaptureActiveWindow
          '    - Captures the currently active window on the screen.
          '
          ' Returns
          '    - Returns a Picture object containing a bitmap of the active
          '      window.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          Public Function CaptureActiveWindow() As Picture
             #If Win32 Then
                Dim hWndActive As Long
                Dim r As Long
             #ElseIf Win16 Then
                Dim hWndActive As Integer
                Dim r As Integer
             #End If
             Dim RectActive As RECT
    
             ' Get a handle to the active/foreground window.
             hWndActive = GetForegroundWindow()
    
             ' Get the dimensions of the window.
             r = GetWindowRect(hWndActive, RectActive)
    
             ' Call CaptureWindow to capture the active window given its
             ' handle and return the Resulting Picture object.
          Set CaptureActiveWindow = CaptureWindow(hWndActive, False, 0, 0, _
                RectActive.Right - RectActive.Left, _
                RectActive.Bottom - RectActive.Top)
          End Function
    
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          ' PrintPictureToFitPage
          '    - Prints a Picture object as big as possible.
          '
          ' Prn
          '    - Destination Printer object.
          '
          ' Pic
          '    - Source Picture object.
          '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
          '
          Public Sub PrintPictureToFitPage(Prn As Printer, Pic As Picture)
             Const vbHiMetric As Integer = 8
             Dim PicRatio As Double
             Dim PrnWidth As Double
             Dim PrnHeight As Double
             Dim PrnRatio As Double
             Dim PrnPicWidth As Double
             Dim PrnPicHeight As Double
    
             ' Determine if picture should be printed in landscape or portrait
             ' and set the orientation.
             If Pic.Height >= Pic.Width Then
                Prn.Orientation = vbPRORPortrait   ' Taller than wide.
             Else
                Prn.Orientation = vbPRORLandscape  ' Wider than tall.
             End If
    
             ' Calculate device independent Width-to-Height ratio for picture.
             PicRatio = Pic.Width / Pic.Height
    
             ' Calculate the dimentions of the printable area in HiMetric.
             PrnWidth = Prn.ScaleX(Prn.ScaleWidth, Prn.ScaleMode, vbHiMetric)
             PrnHeight = Prn.ScaleY(Prn.ScaleHeight, Prn.ScaleMode, vbHiMetric)
             ' Calculate device independent Width to Height ratio for printer.
             PrnRatio = PrnWidth / PrnHeight
    
             ' Scale the output to the printable area.
             If PicRatio >= PrnRatio Then
                ' Scale picture to fit full width of printable area.
                PrnPicWidth = Prn.ScaleX(PrnWidth, vbHiMetric, Prn.ScaleMode)
                PrnPicHeight = Prn.ScaleY(PrnWidth / PicRatio, vbHiMetric, _
                   Prn.ScaleMode)
             Else
                ' Scale picture to fit full height of printable area.
                PrnPicHeight = Prn.ScaleY(PrnHeight, vbHiMetric, Prn.ScaleMode)
                PrnPicWidth = Prn.ScaleX(PrnHeight * PicRatio, vbHiMetric, _
                   Prn.ScaleMode)
             End If
    
             ' Print the picture using the PaintPicture method.
             Prn.PaintPicture Pic, 0, 0, PrnPicWidth, PrnPicHeight
          End Sub
          '--------------------------------------------------------------------
    					
  7. Guarde el proyecto.
  8. Antes de ejecutar este proyecto, compruebe en Referencias del proyecto que existe una referencia a automatización OLE (StdOle2.tlb).
  9. Ejecute el proyecto y pruebe. Debería poder capturar el formulario, el área cliente del formulario, la pantalla y la ventana activa. También podrá imprimir cualquiera de ellos.
NOTA: cuando haya capturado la imagen que desee en un objeto Picture, puede colocarlo con facilidad en el portapapeles utilizando el método SetData del objeto Clipboard.

Referencias

Para obtener más información, haga clic en los números de artículo siguientes para verlos en Microsoft Knowledge Base:
230502 Cómo imprimir un formulario demasiado largo para la pantalla o la página
178076 Cómo usar un PictureBox para controlar la orientación al imprimir un formulario
194580 Cómo imprimir una imagen compuesta desde un RichTextBox
146022 Cómo configurar el control RichTextBox para una impresión WYSIWYG

Propiedades

Id. de artículo: 161299 - Última revisión: jueves, 27 de diciembre de 2007 - Versión: 3.2
La información de este artículo se refiere a:
  • Microsoft Visual Basic 5.0 Learning Edition
  • Microsoft Visual Basic 6.0 Edición de aprendizaje
  • Microsoft Visual Basic 5.0 Professional Edition
  • Microsoft Visual Basic 6.0 Professional Edition
  • Microsoft Visual Basic 5.0 Enterprise Edition
  • Microsoft Visual Basic 6.0 Edición empresarial
  • Microsoft Visual Basic 4.0 Professional Edition
  • Microsoft Visual Basic 4.0 Professional Edition
  • Microsoft Visual Basic 4.0 16-bit Enterprise Edition
  • Microsoft Visual Basic 4.0 32-Bit Enterprise Edition
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kbhowto kbprint KB161299

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