undeclared identifiers

[Y0rkieP]

Im trying to learn how to load jpeg images for display using gdi+. Im using vc++ 2008 express as my compiler options appear to be vc++ or borland. As I cannot afford to pay the kind of money borland is asking, I have had to go with vc++ - even though I hate it. I know there is a free version of borland, but it is commandline and as Im not a seasoned programmer, I really need the comfort of a working ide.

My first problem was that vc++ wouldnt compile without producing 140+ errors. this was due to not including the line:


#pragma comment(lib, "C:\\Program Files\\Microsoft SDKs\\Windows\\v6.1\\Lib\\GdiPlus.lib")


I had to do this even though I had added the include and lib directory for the sdk using tools > options > vc++ directories - and placing the entries at the very top of the lists.

Then I edited the resource file with a text editor to allow me to place 'open' in the file menu of my app. I had to do it manually as vc++ 2008 express doesnt allow resource editimg. With a now working menu, I used openfilename to request the user for a picture:


case IDM_LOAD:
{
OPENFILENAME ofn = {0};

ofn.lStructSize = sizeof(OPENFILENAME);
ofn.hwndOwner = hWnd;
ofn.lpstrFilter = TEXT ("Jpeg Image (*.jpg)\0*.jpg\0All Files (*.*)\0*.*\0");
TCHAR strFileName[MAX_PATH] = {0};
ofn.lpstrFile = strFileName;
ofn.nMaxFile = MAX_PATH;
ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST |OFN_HIDEREADONLY;
ofn.lpstrDefExt = TEXT ("jpg");
ofn.lpstrInitialDir = TEXT ("My Documents\\My Pictures");
GetOpenFileName(&ofn);
MessageBox (hWnd, strFileName, TEXT ("File is:"), MB_OK);

CImage image;
//Image image(L"C:\\path\\pigeon1.jpg");

}
break;


Iv had to use the text macro and changed char szFileName to tchar strFileName, as vc++ seems to require this. the messagebox confirms the app is looking at the correct file. I cannot find anything on loading jpegs using gdi+ with vc++ online. the sdk help seems to indicate I need to use the image class along with graphics object.

i have found 2 examples in the sdk - Image class (they show with bitmap) and CImage class.

CImage class:

CImage provides enhanced bitmap support, including the ability to load and save images in JPEG, GIF, BMP, and Portable Network Graphics (PNG) formats


the example they give is:

CImage image;
// Code to load/create image goes here

// Get a CDC for the image
CDC* pDC = CDC::FromHandle(image.GetDC());

// Use pDC here

image.ReleaseDC();


All I get from CImage is the error 'error C2065: 'CImage' : undeclared identifier'
I have included gdiplus.h and even Gdiplusheaders.h in the file stdafx.h. coding is becomming a real fight, not only with gdi+, but also vc++ and its annoying traits.

please, can anyone help - or at least point me in the direction of something helpfull...

[Notsosuperhero]

Have you included 'atlimage.h' like MSDN says you need to?

Note that C++ is part of the Active Template Library(ATL) not part of GDI+.
Also did you read the notes:

When you create a project using CImage, you must define CString before you include atlimage.h. If your project uses ATL without MFC, include atlstr.h before you include atlimage.h. If your project uses MFC (or if it is an ATL project with MFC support), include afxstr.h before you include atlimage.h.

Likewise, you must include atlimage.h before you include atlimpl.cpp. To accomplish this easily, include atlimage.h in your stdafx.h.

[fred100]

You don't need CImage at all.
For GDI+, use flat apis.
And use OLE or one of the 5 others well-known win32 native methods to load JPEG instead of GDI+