#!/usr/bin/perl

use strict;
use Win32::API;
use Win32::Clipboard;

#############################################
## MAIN BLOCK                              ##
#############################################
print "Using device: " . getDeviceList() . "...\n";

captureImage(0);

print "DONE!\n";
#############################################
## SUBROUTINES                             ##
#############################################
sub getDeviceList {
  my $device = '';
  my $strName = " " x 100; #necessary for the API call
  my $strVer = " " x 100;
  my $i = 0;
  
  my $driverGet = new Win32::API('avicap32.dll', 'capGetDriverDescriptionA', 'IPIPI', 'I');
  if($driverGet->Call($i, $strName, 100, $strVer, 100)) { #make API call to find devices
    $strName = unpack('A*', $strName); #trim trailing nulls
    $device = $strName;
  }
  
  return ($device ? $device : "Error - No device found"); #if theres a device, show it
}

sub captureImage {
  my $iDevice = shift;
  
  my $getD = new Win32::API('user32.dll', 'GetDesktopWindow', '', 'N');
  my $desktopHwnd = $getD->Call(); #need the desktop handle

  my $cCreate = new Win32::API('avicap32.dll', 'capCreateCaptureWindowA', 'PIIIIIII', 'I');
  my $sMsg = new Win32::API('user32.dll', 'SendMessageA', 'IIIP', 'I');
  my $wDestroy = new Win32::API('user32.dll', 'DestroyWindow', 'I', 'I');
  my $wDC = new Win32::API('gdi32.dll', 'CreateCompatibleDC', 'N', 'N'); #create memory DC as a temporary workspace
  my $memHwnd = $wDC->Call($desktopHwnd);
  
  my $handle = $cCreate->Call($iDevice, 0, 0, 0, 640, 480, $memHwnd, 0); #Invisible
  if ($sMsg->Call($handle, 1034, $iDevice, 0)) { #if DRIVER_CONNECT
    $sMsg->Call($handle, 1077, 1 , 0); print "Scale Set...\n";
    $sMsg->Call($handle, 1074, 1, 0); print "Previewing...\n";
    $sMsg->Call($handle, 1076, 1, 0); print "Preview Rate...\n";
    $sMsg->Call($handle, 1054, 0, 0); print "Copying...\n";#copy to clipboard
    sleep 1;
    $wDestroy->Call($handle);
  } else {
    print "Device invalid or in use.\n";
    $wDestroy->Call($handle);
  }
  
  #save the clipboard to file
  my $image = Win32::Clipboard::GetBitmap();
  open (BITMAP, ">current_image.bmp");
  binmode (BITMAP);
  print BITMAP $image;
  close (BITMAP);
}