# encoding: ascii
# api: csharp
# title: Take-Screenshot
# description: This script has a function that allows you to take a screenshot of the entire desktop or of an active window.  Also includes option to save the screenshot to a file.
# version: 0.1
# type: function
# author: Boe Prox
# license: CC0
# function: Take-ScreenShot
# x-poshcode-id: 2021
# x-archived: 2016-11-07T08:27:04
# x-published: 2010-07-25T16:19:00
#
#
Function Take-ScreenShot {
    <#  
.SYNOPSIS  
    Used to take a screenshot of the desktop or the active window. 
.DESCRIPTION  
    Used to take a screenshot of the desktop or the active window and save to an image file if needed.
.PARAMETER screen
    Screenshot of the entire screen
.PARAMETER activewindow
    Screenshot of the active window
.PARAMETER file
    Name of the file to save as. Default is image.bmp
.PARAMETER imagetype
    Type of image being saved. Can use JPEG,BMP,PNG. Default is bitmap(bmp)    
.INPUTS
.OUTPUTS    
.NOTES  
    Name: Take-ScreenShot
    Author: Boe Prox
    DateCreated: 07/25/2010     
.EXAMPLE  
    Take-ScreenShot -activewindow
    Takes a screen shot of the active window        
.EXAMPLE  
    Take-ScreenShot -Screen
    Takes a screenshot of the entire desktop
.EXAMPLE  
    Take-ScreenShot -activewindow -file "C:\image.bmp" -imagetype bmp
    Takes a screenshot of the active window and saves the file named image.bmp with the image being bitmap
.EXAMPLE  
    Take-ScreenShot -screen -file "C:\image.png" -imagetype png    
    Takes a screenshot of the entire desktop and saves the file named image.png with the image being png
#>  
#Requires -Version 2
        [cmdletbinding(
                SupportsShouldProcess = $True,
                DefaultParameterSetName = "screen",
                ConfirmImpact = "low"
        )]
Param (
       [Parameter(
            Mandatory = $False,
            ParameterSetName = "screen",
            ValueFromPipeline = $True)]
            [switch]$screen,
       [Parameter(
            Mandatory = $False,
            ParameterSetName = "window",
            ValueFromPipeline = $False)]
            [switch]$activewindow,
       [Parameter(
            Mandatory = $False,
            ParameterSetName = "",
            ValueFromPipeline = $False)]
            [string]$file, 
       [Parameter(
            Mandatory = $False,
            ParameterSetName = "",
            ValueFromPipeline = $False)]
            [string]
            [ValidateSet("bmp","jpeg","png")]
            $imagetype = "bmp"           
       
)
# C# code
$code = @'
using System;
using System.Runtime.InteropServices;
using System.Drawing;
using System.Drawing.Imaging;
namespace ScreenShotDemo
{
  /// <summary>
  /// Provides functions to capture the entire screen, or a particular window, and save it to a file.
  /// </summary>
  public class ScreenCapture
  {
    /// <summary>
    /// Creates an Image object containing a screen shot the active window
    /// </summary>
    /// <returns></returns>
    public Image CaptureActiveWindow()
    {
      return CaptureWindow( User32.GetForegroundWindow() );
    }
    /// <summary>
    /// Creates an Image object containing a screen shot of the entire desktop
    /// </summary>
    /// <returns></returns>
    public Image CaptureScreen()
    {
      return CaptureWindow( User32.GetDesktopWindow() );
    }    
    /// <summary>
    /// Creates an Image object containing a screen shot of a specific window
    /// </summary>
    /// <param name="handle">The handle to the window. (In windows forms, this is obtained by the Handle property)</param>
    /// <returns></returns>
    private Image CaptureWindow(IntPtr handle)
    {
      // get te hDC of the target window
      IntPtr hdcSrc = User32.GetWindowDC(handle);
      // get the size
      User32.RECT windowRect = new User32.RECT();
      User32.GetWindowRect(handle,ref windowRect);
      int width = windowRect.right - windowRect.left;
      int height = windowRect.bottom - windowRect.top;
      // create a device context we can copy to
      IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
      // create a bitmap we can copy it to,
      // using GetDeviceCaps to get the width/height
      IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc,width,height);
      // select the bitmap object
      IntPtr hOld = GDI32.SelectObject(hdcDest,hBitmap);
      // bitblt over
      GDI32.BitBlt(hdcDest,0,0,width,height,hdcSrc,0,0,GDI32.SRCCOPY);
      // restore selection
      GDI32.SelectObject(hdcDest,hOld);
      // clean up
      GDI32.DeleteDC(hdcDest);
      User32.ReleaseDC(handle,hdcSrc);
      // get a .NET image object for it
      Image img = Image.FromHbitmap(hBitmap);
      // free up the Bitmap object
      GDI32.DeleteObject(hBitmap);
      return img;
    }
    /// <summary>
    /// Captures a screen shot of the active window, and saves it to a file
    /// </summary>
    /// <param name="filename"></param>
    /// <param name="format"></param>
    public void CaptureActiveWindowToFile(string filename, ImageFormat format)
    {
      Image img = CaptureActiveWindow();
      img.Save(filename,format);
    }
    /// <summary>
    /// Captures a screen shot of the entire desktop, and saves it to a file
    /// </summary>
    /// <param name="filename"></param>
    /// <param name="format"></param>
    public void CaptureScreenToFile(string filename, ImageFormat format)
    {
      Image img = CaptureScreen();
      img.Save(filename,format);
    }    
   
    /// <summary>
    /// Helper class containing Gdi32 API functions
    /// </summary>
    private class GDI32
    {
      
      public const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter
      [DllImport("gdi32.dll")]
      public static extern bool BitBlt(IntPtr hObject,int nXDest,int nYDest,
        int nWidth,int nHeight,IntPtr hObjectSource,
        int nXSrc,int nYSrc,int dwRop);
      [DllImport("gdi32.dll")]
      public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC,int nWidth,
        int nHeight);
      [DllImport("gdi32.dll")]
      public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
      [DllImport("gdi32.dll")]
      public static extern bool DeleteDC(IntPtr hDC);
      [DllImport("gdi32.dll")]
      public static extern bool DeleteObject(IntPtr hObject);
      [DllImport("gdi32.dll")]
      public static extern IntPtr SelectObject(IntPtr hDC,IntPtr hObject);
    }

    /// <summary>
    /// Helper class containing User32 API functions
    /// </summary>
    private class User32
    {
      [StructLayout(LayoutKind.Sequential)]
      public struct RECT
      {
        public int left;
        public int top;
        public int right;
        public int bottom;
      }
      [DllImport("user32.dll")]
      public static extern IntPtr GetDesktopWindow();
      [DllImport("user32.dll")]
      public static extern IntPtr GetWindowDC(IntPtr hWnd);
      [DllImport("user32.dll")]
      public static extern IntPtr ReleaseDC(IntPtr hWnd,IntPtr hDC);
      [DllImport("user32.dll")]
      public static extern IntPtr GetWindowRect(IntPtr hWnd,ref RECT rect);
      [DllImport("user32.dll")]
      public static extern IntPtr GetForegroundWindow();      
    }
  }
}
'@
#User Add-Type to import the code
add-type $code -ReferencedAssemblies 'System.Windows.Forms','System.Drawing'
#Create the object for the Function
$capture = New-Object ScreenShotDemo.ScreenCapture

#Take screenshot of the entire screen
If ($Screen) {
    Write-Verbose "Taking screenshot of entire desktop"
    #Save to a file
    If ($file) {
        If ($file -eq "") {
            $file = "$pwd\image.bmp"
            }
        Write-Verbose "Creating screen file: $file with imagetype of $imagetype"
        $capture.CaptureScreenToFile($file,$imagetype)
        }
    Else {
        $capture.CaptureScreen()
        }
    }
#Take screenshot of the active window    
If ($ActiveWindow) {
    Write-Verbose "Taking screenshot of the active window"
    #Save to a file
    If ($file) {
        If ($file -eq "") {
            $file = "$pwd\image.bmp"
            }
        Write-Verbose "Creating activewindow file: $file with imagetype of $imagetype"
        $capture.CaptureActiveWindowToFile($file,$imagetype)
        }
    Else {
        $capture.CaptureActiveWindow()
        }    
    }    
}
