Take screenshot and save it as jpg

[SpecialForce]

Hello everyone,
I am trying to take a screenshot and save it as jpg. I have found a code and save it as bmp but the file size is pretty big. After searching a lot I found this thread http://www.daniweb.com/forums/thread327090.html but I can't compile the code... :( I am trying to compile this code:

#include "stdafx.h"
#include <GdiPlus.h>

#pragma comment( lib, "gdiplus" )

void gdiscreen()
{
	using namespace Gdiplus;
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

	{
		HDC scrdc, memdc;
		HBITMAP membit;
		scrdc = ::GetDC(0);
		int Height = GetSystemMetrics(SM_CYSCREEN);
		int Width = GetSystemMetrics(SM_CXSCREEN);
		memdc = CreateCompatibleDC(scrdc);
		membit = CreateCompatibleBitmap(scrdc, Width, Height);
		HBITMAP hOldBitmap =(HBITMAP) SelectObject(memdc, membit);
		BitBlt(memdc, 0, 0, Width, Height, scrdc, 0, 0, SRCCOPY);

		Gdiplus::Bitmap bitmap(membit, NULL);
		CLSID clsid;
		GetEncoderClsid(L"image/jpeg", &clsid);
		bitmap.Save(L"D:\\screen.jpeg", &clsid);

		SelectObject(memdc, hOldBitmap);

		DeleteObject(memdc);

		DeleteObject(membit);

		::ReleaseDC(0,scrdc);
	}

	GdiplusShutdown(gdiplusToken);
}

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
	using namespace Gdiplus;
	UINT  num = 0;          // number of image encoders
	UINT  size = 0;         // size of the image encoder array in bytes

	ImageCodecInfo* pImageCodecInfo = NULL;

	GetImageEncodersSize(&num, &size);
	if(size == 0)
		return -1;  // Failure

	pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
	if(pImageCodecInfo == NULL)
		return -1;  // Failure

	GetImageEncoders(num, size, pImageCodecInfo);

	for(UINT j = 0; j < num; ++j)
	{
		if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
		{
			*pClsid = pImageCodecInfo[j].Clsid;
			free(pImageCodecInfo);
			return j;  // Success
		}    
	}

	free(pImageCodecInfo);
	return 0;
}

but I am getting the following error:

error C3861: 'GetEncoderClsid': identifier not found

I know it's something really silly but I am new to c++ programming and need a bit help. Can you please help me?

Thanks in advance :)

[daviddoria]

If that is your entire program, you are definitely missing main(). From main, it looks like you should call gdiscreen(). The "identifier not found" would be fixed by adding a declaration before you call the function:

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid);

David

[SpecialForce]

Thanks a lot for your reply David, but I can't call that function... You are right about main(), so here is the code now:

#include "stdafx.h"
#include <GdiPlus.h>
 
#pragma comment( lib, "gdiplus" )

void gdiscreen()
{
	using namespace Gdiplus;
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

	{
		HDC scrdc, memdc;
		HBITMAP membit;
		scrdc = ::GetDC(0);
		int Height = GetSystemMetrics(SM_CYSCREEN);
		int Width = GetSystemMetrics(SM_CXSCREEN);
		memdc = CreateCompatibleDC(scrdc);
		membit = CreateCompatibleBitmap(scrdc, Width, Height);
		HBITMAP hOldBitmap =(HBITMAP) SelectObject(memdc, membit);
		BitBlt(memdc, 0, 0, Width, Height, scrdc, 0, 0, SRCCOPY);

		Gdiplus::Bitmap bitmap(membit, NULL);
		CLSID clsid;
		GetEncoderClsid(L"image/jpeg", &clsid);
		bitmap.Save(L"C:\\screen.jpeg", &clsid);

		SelectObject(memdc, hOldBitmap);

		DeleteObject(memdc);

		DeleteObject(membit);

		::ReleaseDC(0,scrdc);
	}

	GdiplusShutdown(gdiplusToken);
}

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
	using namespace Gdiplus;
	UINT  num = 0;          // number of image encoders
	UINT  size = 0;         // size of the image encoder array in bytes

	ImageCodecInfo* pImageCodecInfo = NULL;

	GetImageEncodersSize(&num, &size);
	if(size == 0)
		return -1;  // Failure

	pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
	if(pImageCodecInfo == NULL)
		return -1;  // Failure

	GetImageEncoders(num, size, pImageCodecInfo);

	for(UINT j = 0; j < num; ++j)
	{
		if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
		{
			*pClsid = pImageCodecInfo[j].Clsid;
			free(pImageCodecInfo);
			return j;  // Success
		}    
	}

	free(pImageCodecInfo);
	return 0;
}

int main()
{
	int GetEncoderClsid(const WCHAR* format, CLSID* pClsid);
	gdiscreen();
}

I am still getting the same error...

[daviddoria]

The declaration of GetEncoderClsid must come before the definition of gdiscreen() (since gdiscreen() calls GetEncoderClsid). A good practice is to put all of your function declarations right after the includes. Putting it inside main() as you have done doesn't make sense.

[SpecialForce]

Thanks a ton! I finally done it!

1st way:

#include "stdafx.h"
#include <windows.h>
#include <GdiPlus.h>
#pragma comment( lib, "gdiplus" )

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
	using namespace Gdiplus;
	UINT  num = 0;          // number of image encoders
	UINT  size = 0;         // size of the image encoder array in bytes

	ImageCodecInfo* pImageCodecInfo = NULL;

	GetImageEncodersSize(&num, &size);
	if(size == 0)
		return -1;  // Failure

	pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
	if(pImageCodecInfo == NULL)
		return -1;  // Failure

	GetImageEncoders(num, size, pImageCodecInfo);

	for(UINT j = 0; j < num; ++j)
	{
		if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
		{
			*pClsid = pImageCodecInfo[j].Clsid;
			free(pImageCodecInfo);
			return j;  // Success
		}    
	}

	free(pImageCodecInfo);
	return 0;
}

int main()
{
	using namespace Gdiplus;
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

	{
		HDC scrdc, memdc;
		HBITMAP membit;
		scrdc = ::GetDC(0);
		int Height = GetSystemMetrics(SM_CYSCREEN);
		int Width = GetSystemMetrics(SM_CXSCREEN);
		memdc = CreateCompatibleDC(scrdc);
		membit = CreateCompatibleBitmap(scrdc, Width, Height);
		HBITMAP hOldBitmap =(HBITMAP) SelectObject(memdc, membit);
		BitBlt(memdc, 0, 0, Width, Height, scrdc, 0, 0, SRCCOPY);

		Gdiplus::Bitmap bitmap(membit, NULL);
		CLSID clsid;
		GetEncoderClsid(L"image/jpeg", &clsid);
		bitmap.Save(L"C:\\screen.jpeg", &clsid);

		SelectObject(memdc, hOldBitmap);

		DeleteObject(memdc);

		DeleteObject(membit);

		::ReleaseDC(0,scrdc);
	}

	GdiplusShutdown(gdiplusToken);
}

2nd way (I think better):

#include "stdafx.h"
#include <windows.h>
#include <GdiPlus.h>
#pragma comment( lib, "gdiplus" )

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid);
void gdiscreen();

void gdiscreen()
{
	using namespace Gdiplus;
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
	
	{
		HDC scrdc, memdc;
		HBITMAP membit;
		scrdc = ::GetDC(0);
		int Height = GetSystemMetrics(SM_CYSCREEN);
		int Width = GetSystemMetrics(SM_CXSCREEN);
		memdc = CreateCompatibleDC(scrdc);
		membit = CreateCompatibleBitmap(scrdc, Width, Height);
		HBITMAP hOldBitmap =(HBITMAP) SelectObject(memdc, membit);
		BitBlt(memdc, 0, 0, Width, Height, scrdc, 0, 0, SRCCOPY);

		Gdiplus::Bitmap bitmap(membit, NULL);
		CLSID clsid;
		GetEncoderClsid(L"image/jpeg", &clsid);
		bitmap.Save(L"C:\\screen.jpeg", &clsid);

		SelectObject(memdc, hOldBitmap);

		DeleteObject(memdc);

		DeleteObject(membit);

		::ReleaseDC(0,scrdc);
	}

	GdiplusShutdown(gdiplusToken);
}

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
	using namespace Gdiplus;
	UINT  num = 0;          // number of image encoders
	UINT  size = 0;         // size of the image encoder array in bytes

	ImageCodecInfo* pImageCodecInfo = NULL;

	GetImageEncodersSize(&num, &size);
	if(size == 0)
		return -1;  // Failure

	pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
	if(pImageCodecInfo == NULL)
		return -1;  // Failure

	GetImageEncoders(num, size, pImageCodecInfo);

	for(UINT j = 0; j < num; ++j)
	{
		if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
		{
			*pClsid = pImageCodecInfo[j].Clsid;
			free(pImageCodecInfo);
			return j;  // Success
		}    
	}

	free(pImageCodecInfo);
	return 0;
}

int main()
{	
	gdiscreen();
}

I done it with two ways but the second (the one you told me to do), I think, is better because is better to have source code splitted in functions. Thanks a ton again, you not only solve my problem but also make me learn how to declare functions!

[daviddoria]

Excellent - I'm glad it's working, and I'm even more glad you've learned something! Yes, you definitely want to split the code into as many functions as possible (ok, ok, don't go crazy), but more functions typically makes code easier to debug and test.

Also, please mark the thread as solved.

David

[SpecialForce]

Marking the thread as solved is the least I can do to thank you! :)

[billa007]

How to get the jpeg bits in order to save it in the blob field of the database.

[daviddoria]

This seems like a totally separate question. You should start a new thread.