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Display screen remotely

David Lake · 2013-08-08T01:40:32

I have a program I made for remotely controlling PC's that uses bitblt, bitmaps, a bit of processing and compression and I would like to improve the way it captures and displays the desktop using SlimDX if that can be used to increase performance. At the moment the capture side is very heavy on the CPU, I use the threadpool for threading and split the screen capture and processing/sending of frames into different threads but would like to reduce CPU utilization without compromising performance if possible. Main problem is I cant control the login screen I would like to know if theres a way arround that. Also I need a faster way(than GDI+) to scale the images before sending, I'm hoping SlimDX can speed this up using the GPU Is there a relatively easy way to use SlimDX to capture the screen and display it remotely thats at least as fast as using bitblt, GDI+ and bitmaps?

General and Gameplay Programming Programming

Started by David Lake June 27, 2013 08:18 PM

58 comments, last by David Lake 10 years, 8 months ago

David Lake

117

Author

June 29, 2013 03:18 AM

Just make sure to pass a NULL pointer the first time this function is called

Please clarify?

Vortez

2,714

June 29, 2013 03:49 AM

I dont know how it's done in c# but in c++ you have to initalize pointers to NULL before using them most of the time, and this is one of those time, otherwise it will crash by calling delete [] on invalid memory location.

ex. (in c++)


// When program start

BYTE *pBuffer = NULL;

...

// Later...

int BufferSize = GenScreenShot(pBuffer);

...

// Just before quitting program

if(pBuffer)

    delete [] pBuffer;

You should include "Windows.h", it has every windows related header inside it.

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David Lake

117

Author

June 29, 2013 04:09 AM

Oh right, in C# we make a byte array like this: var array=new byte[size]; (var specifies the type implicitly which I prefer) then garbage collection automatically gets rid of it.

I included Windows.h and WinGDI.h but theres still 150 errors and BMISize is undefined.

Also in DrawCursor (you spelled it incorrectly) WinVer and _WIN_VISTA_ are undefined.

Vortez

2,714

June 29, 2013 04:30 AM

This compile just fine with visual studio


#include "Windows.h"

const int BMISize = sizeof(BITMAPINFOHEADER) + 256 * sizeof(RGBQUAD);

int GenScreenShot(BYTE *pBuffer)
{
	HWND hDesktopWnd = GetDesktopWindow();
	HDC  hdc = GetDC(hDesktopWnd);

	int x = 0;
	int y = 0;
	int w = GetSystemMetrics(SM_CXSCREEN);
	int h = GetSystemMetrics(SM_CYSCREEN);

	HDC     s_hdc   = CreateCompatibleDC(hdc);
	HBITMAP hbmp    = CreateCompatibleBitmap(hdc, w,h);
	HBITMAP ex_hbmp = (HBITMAP)SelectObject(s_hdc, hbmp);

/////////////////////////////////////////////////////////////////////////////////////////

	// Copy the screen image in our bitmap
	BitBlt(s_hdc, x,y,w,h, hdc, x,y, SRCCOPY);

	// Draw the cursor over the image
	//if(ShowCursor)
	//	DrawCurcor(s_hdc);
	
	ReleaseDC(hDesktopWnd, hdc);

/////////////////////////////////////////////////////////////////////////////////////////

	if(pBuffer)
		delete [] pBuffer;

	DWORD NumPixels = w * h;
	DWORD BufSize = NumPixels * 3;

	// Allocate buffers
	pBuffer = new BYTE[BufSize];
	ZeroMemory(pBuffer, BufSize);

	// Allocate a BITMAPINFO buffer 
	LPBITMAPINFO lpbi = (LPBITMAPINFO)(new BYTE[BMISize]);
	ZeroMemory(lpbi, sizeof(BITMAPINFO));
	lpbi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);

	// De-select our hbmp
	SelectObject(s_hdc, ex_hbmp);

	// Get information about the screenshot image format
	GetDIBits(s_hdc, hbmp, 0, h, NULL, lpbi, DIB_RGB_COLORS);
	lpbi->bmiHeader.biCompression = BI_RGB;
	// Make sure it's gonna be extracted in 24 bits format
	lpbi->bmiHeader.biBitCount  = 24;
	lpbi->bmiHeader.biSizeImage = BufSize;

	// Extract the image in 24 bits format
	GetDIBits(s_hdc, hbmp, 0, h, pBuffer, lpbi, DIB_RGB_COLORS);

	// Delete the BITMAPINFO buffer
	if(lpbi)
		delete [] lpbi;

	// Release the bitmap handles
	if(SelectObject(s_hdc, hbmp)){
		DeleteObject(hbmp);
		DeleteDC(s_hdc);
	}

	return BufSize;
}

void DeleteScreenShotBuffer(BYTE *pBuffer)
{
	if(pBuffer)
		delete [] pBuffer;
}

int main()
{
	BYTE *pBuffer = NULL;

	GenScreenShot(pBuffer);
	
	DeleteScreenShotBuffer(pBuffer);

	return 0;
}

It's a console program but it shouldn't be too hard to make a dll with it.

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Vortez

2,714

June 29, 2013 04:33 AM

Yea i commented DrawCursor because it's not very usefull to see 2 cursor one under the other, just comment the function.

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Vortez

2,714

June 29, 2013 04:46 AM

If you really wanna use it just remove some code (lol, never noticed the typo before, thx)


void DrawCursor(HDC hDC)
{
	CURSORINFO CursorInfo;
	CursorInfo.cbSize = sizeof(CURSORINFO);
	GetCursorInfo(&CursorInfo);

	//static DWORD Version = WinVer.DetectWindowsVersion();
	//static HCURSOR hCur = LoadCursor(NULL, IDC_ARROW);

	DWORD CursorWidth  = GetSystemMetrics(SM_CXCURSOR);
	DWORD CursorHeight = GetSystemMetrics(SM_CYCURSOR);

	POINT CursorPos;
	GetCursorPos(&CursorPos);
	
	// Needed for XP or older windows
	/*if(Version < _WIN_VISTA_){
		CursorPos.x -= CursorWidth  >> 2;
		CursorPos.y -= CursorHeight >> 2;
	}*/

	DrawIconEx(hDC, CursorPos.x, CursorPos.y, CursorInfo.hCursor, CursorWidth, CursorHeight, 0, NULL, DI_NORMAL);
}

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Vortez

2,714

June 29, 2013 04:50 AM

Also, i've created an empty console project, so don't try to include stdafx.h

My Projects

David Lake

117

Author

June 29, 2013 06:00 AM

I still cant figure out the errors in wingdi.h, winuser.h, winspool.h, wincon.h, imm.h and commdlg.h, they are mostly things like identifier PDEVMODEW is undefined.

Vortez

2,714

June 29, 2013 06:13 AM

Maybe your forgot to turn unicode off? what errors do you get? can you paste them?

My Projects

David Lake

117

Author

June 29, 2013 06:25 AM

Error 1 error : identifier "POINT" is undefined Error 2 error : identifier "POINT" is undefined Error 3 error : identifier "WORD" is undefined Error 4 error : identifier "WORD" is undefined Error 5 error : identifier "DEVMODEA" is undefined Error 6 error : identifier "DEVMODEW" is undefined Error 7 error : identifier "DEVMODEA" is undefined Error 8 error : identifier "DEVMODEW" is undefined Error 9 error : identifier "BLENDFUNCTION" is undefined Error 10 error : identifier "BLENDFUNCTION" is undefined Error 11 error : identifier "LOGFONTA" is undefined Error 12 error : identifier "LOGFONTA" is undefined Error 13 error : identifier "LOGFONTA" is undefined Error 14 error : identifier "LOGFONTA" is undefined Error 15 error : identifier "LOGFONTA" is undefined Error 16 error : identifier "LOGFONTW" is undefined Error 17 error : identifier "LOGFONTW" is undefined Error 18 error : identifier "LOGFONTW" is undefined Error 19 error : identifier "LOGFONTW" is undefined Error 20 error : identifier "LOGFONTW" is undefined Error 21 error : identifier "LOGFONTA" is undefined Error 22 error : identifier "LOGFONTW" is undefined Error 23 error : variable "ChangeDisplaySettingsA" Error 24 error : identifier "DEVMODEA" is undefined Error 25 error : identifier "lpDevMode" is undefined Error 26 error : expected a ")" C:\Program Error 27 error : variable "ChangeDisplaySettingsW" Error 28 error : identifier "DEVMODEW" is undefined Error 29 error : expected a ")" C:\Program Error 30 error : "DEVMODEA" is not a type name Error 31 error : "DEVMODEW" is not a type name Error 32 error : "DEVMODEA" is not a type name Error 33 error : "DEVMODEW" is not a type name Error 34 error : "DEVMODEA" is not a type name Error 35 error : "DEVMODEW" is not a type name Error 36 error : identifier "PDISPLAY_DEVICEA" is undefined Error 37 error : identifier "PDISPLAY_DEVICEW" is undefined Error 38 error : identifier "LF_FACESIZE" is undefined Error 39 error : identifier "LPDEVMODEA" is undefined Error 40 error : identifier "LPDEVMODEW" is undefined Error 41 error : identifier "LPDEVMODEA" is undefined Error 42 error : identifier "LPDEVMODEW" is undefined Error 43 error : identifier "LPDEVMODEA" is undefined Error 44 error : identifier "LPDEVMODEW" is undefined Error 45 error : identifier "LPDEVMODEA" is undefined Error 46 error : identifier "LPDEVMODEW" is undefined Error 47 error : identifier "LPDEVMODEA" is undefined Error 48 error : identifier "LPDEVMODEW" is undefined Error 49 error : identifier "LPDEVMODEA" is undefined Error 50 error : identifier "LPDEVMODEW" is undefined Error 51 error : identifier "PDEVMODEA" is undefined Error 52 error : identifier "PDEVMODEA" is undefined Error 53 error : identifier "PDEVMODEW" is undefined Error 54 error : identifier "PDEVMODEW" is undefined Error 55 error : identifier "PDEVMODEA" is undefined Error 56 error : identifier "PDEVMODEA" is undefined Error 57 error : identifier "PDEVMODEW" is undefined Error 58 error : identifier "PDEVMODEW" is undefined Error 59 error : identifier "LPDEVMODEA" is undefined Error 60 error : identifier "LPDEVMODEA" is undefined Error 61 error : identifier "PDEVMODEA" is undefined Error 62 error : identifier "PDEVMODEW" is undefined Error 63 error : identifier "LPLOGFONTA" is undefined Error 64 error : identifier "LPLOGFONTW" is undefined Error 65 error : identifier "LPDEVMODE" is undefined Error 66 error : identifier "LPLOGFONTA" is undefined Error 67 error : identifier "LPLOGFONTW" is undefined Error 68 error : identifier "LPLOGFONTA" is undefined Error 69 error : identifier "LPLOGFONTW" is undefined Error 70 error : identifier "TEXTMETRICA" is undefined Error 71 error : identifier "TEXTMETRICA" is undefined Error 72 error : identifier "LPTEXTMETRICA" is undefined Error 73 error #10298: problem during post C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\WinGDI.h 285 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\WinGDI.h 286 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\WinGDI.h 287 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\WinGDI.h 288 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 1192 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 1202 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 1218 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 1230 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 3959 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 3974 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10746 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10749 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10752 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10753 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10754 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10767 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10770 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10773 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10774 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10775 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10823 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10831 1 QuickLZ
may not be initialized C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10951 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10952 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10952 1 QuickLZ
Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10952 1 QuickLZ
may not be initialized C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10957 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10958 1 QuickLZ
Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10958 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10971 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10980 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 10999 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 11006 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 11021 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 11029 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 11047 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winuser.h 11055 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\wincon.h 209 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 79 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 102 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 205 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 208 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 221 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 224 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 377 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 402 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 443 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 469 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1181 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1186 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1927 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1928 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1937 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1938 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1953 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1954 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1962 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1963 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1976 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 1979 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 3041 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\winspool.h 3047 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\commdlg.h 638 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\commdlg.h 661 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\commdlg.h 958 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\imm.h 254 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\imm.h 255 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\imm.h 262 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\imm.h 263 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\WinGDI.h 2843 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\WinGDI.h 3184 1 QuickLZ
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\WinGDI.h 4304 1 QuickLZ
processing of parallel object compilation C:\Users\Administrator\Documents\Visual Studio 2010\Projects\QuickLZ\QuickLZ\icl QuickLZ

Display screen remotely

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