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/*Window capture example*/
#include "stdafx.h"
using namespace Gdiplus;
using namespace Gdiplus::DllExports;
// using namespace GdiPlus;
// #define SCREENWIDTH GetSystemMetrics(SM_CXSCREEN)
// #define SCREENHEIGHT GetSystemMetrics(SM_CYSCREEN)
int main()
{
/////////////////////////////////////////////////////////////////////////////////////////////////////
// PART 1 - PREPARATION OF THE BASIC BITMAP
/////////////////////////////////////////////////////////////////////////////////////////////////////
HWND HCapture = FindWindow(NULL, _T("Map Viewer") ); // get window handle
// HWND HCapture = GetDesktopWindow(); // get desktop handle (but can be handle of any window)
if(!IsWindow(HCapture)) return 1;
/*
BOOL PrintWindow(
HWND hwnd, // A handle to the window that will be copied.
HDC hdcBlt, // A handle to the device context.
UINT nFlags // The drawing options: PW_CLIENTONLY
// Only the client area of the window is copied to hdcBlt. By default, the entire window is copied.
);
*/
// get window dimensions
RECT rect; GetWindowRect(HCapture, &rect);
size_t dx = rect.right - rect.left;
size_t dy = rect.bottom - rect.top;
// create BITMAPINFO structure
// used by CreateDIBSection
BITMAPINFO info;
info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
info.bmiHeader.biWidth = dx;
info.bmiHeader.biHeight = dy;
info.bmiHeader.biPlanes = 1;
info.bmiHeader.biBitCount = 24;
info.bmiHeader.biCompression = BI_RGB;
info.bmiHeader.biSizeImage = 0;
info.bmiHeader.biXPelsPerMeter = 0;
info.bmiHeader.biYPelsPerMeter = 0;
info.bmiHeader.biClrUsed = 0;
info.bmiHeader.biClrImportant = 0;
// a bitmap handle and a pointer its bit data
HBITMAP HBitmap = 0;
BYTE* memory = 0; // ppvBits - A pointer to a variable that will receive a pointer to the location of the DIB bit values. See CreateDIBSection()
/** We should create Bitmap first and then Device Context,
however when I want to create snapshot of window, I need to use
fnc PrintWindow to copy the visual window to Device Context.
So I need to create DC first. The DC will be compatible with
current screen.
*/
// 1. FIRST we need to Create DC for PrintWindow function
// HDC HDevice = GetDC(HCapture);
HDC HDevice = CreateCompatibleDC(NULL);
// 2. SECOND we need to CREATE BITMAP (Device Independent Bitmap)
// HBitmap = CreateCompatibleBitmap(HDevice, dx, dy);
HBitmap = CreateDIBSection(HDevice, &info, DIB_RGB_COLORS, (void**)&memory, 0, 0);
DWORD dw = GetLastError();
// 3. Make HBitmap to be destination of the following work
SelectObject(HDevice, HBitmap);
///////////////////////////////////////////////////////////////////////////////////////////
// PART 2 - GET VISUAL CONTENT OF WINDOW //
// AND SAVE IT TO BITMAP //
///////////////////////////////////////////////////////////////////////////////////////////
// THIS WAS WRONG DECLARATION: unsigned int * pBitmap;
GpBitmap *pBitmap = NULL; // type Gdiplus::GpBitmap
if (!PrintWindow(HCapture, HDevice, PW_CLIENTONLY)) return 2;
// INIT GDI
ULONG_PTR gdiplusToken;
GdiplusStartupInput gdiplusStartupInput;
GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
if (!gdiplusToken) return 3;
// pBitmap is null.
int state = Gdiplus::DllExports::GdipCreateBitmapFromHBITMAP(HBitmap, 0, &pBitmap);
ReleaseDC(HCapture, HDevice);
// if(!HBitmap || !memory) return 1;
/*
The GetWindowDC function retrieves the device context (DC) for
the entire window, including title bar, menus, and scroll bars.
A window device context permits painting anywhere in a window */
// blit the contents of the desktop (winDC)
// to the bitmap (selected in memDC)
HDC winDC = GetWindowDC(HCapture);
HDC memDC = CreateCompatibleDC(winDC);
SelectObject(memDC, HBitmap);
BitBlt(memDC, 0, 0, dx, dy, winDC, 0, 0, SRCCOPY);
DeleteDC(memDC);
ReleaseDC(HCapture, winDC);
/** THIS IS WRONG! VARIABLE CANNOT POINT TO NOWHERE!*/
// char *buffer; // First set the type and range and then make pointer:
char *buffer = new char[50]; // RIGHT DECLARATION
sprintf(buffer,"capture%d%d.bmp",dx,dy);
// create bitmap file
std::basic_ofstream <char> file(buffer, std::ios::binary);
if(!file) { DeleteObject(HBitmap); return 1; }
// initialize bitmap file headers
BITMAPFILEHEADER fileHeader;
BITMAPINFOHEADER infoHeader;
fileHeader.bfType = 0x4d42;
fileHeader.bfSize = 0;
fileHeader.bfReserved1 = 0;
fileHeader.bfReserved2 = 0;
fileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
infoHeader.biSize = sizeof(infoHeader);
infoHeader.biWidth = dx;
infoHeader.biHeight = dy;
infoHeader.biPlanes = 1;
infoHeader.biBitCount = 24;
infoHeader.biCompression = BI_RGB;
infoHeader.biSizeImage = 0;
infoHeader.biXPelsPerMeter = 0;
infoHeader.biYPelsPerMeter = 0;
infoHeader.biClrUsed = 0;
infoHeader.biClrImportant = 0;
// save file headers
file.write((char*)&fileHeader, sizeof(fileHeader));
file.write((char*)&infoHeader, sizeof(infoHeader));
// save 24-bit bitmap data
int wbytes = (((24*dx + 31) & (~31))/8);
int tbytes = (((24*dx + 31) & (~31))/8)*dy;
file.write((char*)memory, tbytes);
// delete bitmap
DeleteObject(HBitmap);
HBitmap = 0;
memory = 0;
GdiplusShutdown(gdiplusToken);
return 0;
} |
