Jump to content
  • Advertisement
Sign in to follow this  
MatsVed

Creating a child window?

This topic is 2994 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I'm creating an installer in C++ (or at least I'm trying to...) I messed around a bit to get the standard Win32 application to display a bitmap on the main window. Now I'd like a child window on top of the main window that is borderless! I couldn't actually find any examples of this on Google Image Search, so I made a mockup: ; This is what my InitInstance() function looks like:
//
//   FUNCTION: InitInstance(HINSTANCE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;
   HWND ChildWnd;

   hInst = hInstance; // Store instance handle in our global variable

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
   ChildWnd = CreateWindow(szChldWndClass, szTitle, WS_OVERLAPPEDWINDOW,
	   CW_USEDEFAULT, WS_VISIBLE | WS_CHILD | BS_VCENTER | BS_CENTER, 
	   500, 100, NULL, NULL, hInst, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   ShowWindow(ChildWnd, nCmdShow);
   UpdateWindow(hWnd);
   UpdateWindow(ChildWnd);

   return TRUE;
}


The child window still doesn't display! Why is this?

Share this post


Link to post
Share on other sites
Advertisement
You need to define the parent in CreateWindowEx if you want to make it a real child window


ChildWnd = CreateWindow(szChldWndClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, WS_VISIBLE | WS_CHILD | BS_VCENTER | BS_CENTER,
500, 100, hWnd /* Parent Parameter */, NULL, hInst, NULL);


Share this post


Link to post
Share on other sites
You have
ChildWnd = CreateWindow(szChldWndClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, WS_VISIBLE | WS_CHILD | BS_VCENTER | BS_CENTER,
500, 100, NULL, NULL, hInst, NULL);
You want
ChildWnd = CreateWindow(szChldWndClass, szTitle, WS_OVERLAPPEDWINDOW | WS_VISIBLE | WS_CHILD | BS_VCENTER | BS_CENTER,
CW_USEDEFAULT, CW_USEDEFAULT,
500, 100, NULL, NULL, hInst, NULL);
I question the BS_VCENTER and BS_CENTER styles though...
[edit] Plus you want to include the parent hWnd as Rattrap specified of course
[edit again] Plus WS_OVERLAPPEDWINDOW will give you a border ... but get the thing to display first and then mess with the styles I'd say.

Share this post


Link to post
Share on other sites
Thanks again!
Still doesn't display...

Should I call BeginPaint() on the childwindow? And where should I call it?

Share this post


Link to post
Share on other sites
Also, when you create your main window:
hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

In order you have
CW_USEDEFAULT, // x pos
0, // y pos
CW_USEDEFAULT, // width
0, // height
So you create your parent window with a height of 0. Nothing will display, and your button/editbox/whatever child window you are making of course won't display because there is no parent window to display.
try CW_USEDEFAULT, CW_USEDEFAULT, 600, 200
or something since your child window is 500x100 and needs to fit inside it.

Note that CW_USEDEFAULT will pretty much plop the window anywhere, and the child. If you know where you want them, specify.

Share this post


Link to post
Share on other sites
You might want to use CreateWindowEx instead of the CreateWindow macro, so that you can specify WS_EX_TRANSPARENT, which might be necessary to achieve the effect shown in your mock up.

Also, and probably more importantly, you need to specify an identifier for the window in the hMenu parameter.

Quote:

hMenu
[in] Handle to a menu, or specifies a child-window identifier, depending on the window style. For an overlapped or pop-up window, hMenu identifies the menu to be used with the window; it can be NULL if the class menu is to be used. For a child window, hMenu specifies the child-window identifier, an integer value used by a dialog box control to notify its parent about events. The application determines the child-window identifier; it must be unique for all child windows with the same parent window.


Identifiers are usually #define[d] in the resource header.

Share this post


Link to post
Share on other sites
I am not sure exactly what you are trying to achieve.
You want a see through Box where you can display Text. Is that it?
WS_EX_TRANSPARENT should do the Trick.
The only Alternative, which requires a bit of Work, is creating a normal Child Window and then during WM_PAINT, send a Message to the Parent to request it to paint itself in the Child's Device Context, then the Child paints on top of that. This second Option would give you also the possibility of Alphablending.
Which is a very nice Effect.

Share this post


Link to post
Share on other sites
You're probably drawing over the top of your child window. Try adding WS_CLIPCHILDREN to the parent. In addition to what popsoftheyear and rattrap said.

Share this post


Link to post
Share on other sites
I don't want my child window to be transparent!
I just want it to be like a normal window, but without a border!

I already created an ID... I had to, to be able to call LoadString() in the beginning;

	// Initialize global strings
LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadString(hInstance, IDC_INSTALLER, szWindowClass, MAX_LOADSTRING);
LoadString(hInstance, IDC_INSTALLER_CHLD, szChldWndClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);






I added the ID to the hMenu param, and used WS_CLIPCHILDREN on the parent:

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;
HWND ChildWnd;

hInst = hInstance; // Store instance handle in our global variable

hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
ChildWnd = CreateWindow(szChldWndClass, szTitle, WS_OVERLAPPEDWINDOW | WS_VISIBLE |
WS_CHILD | BS_VCENTER | BS_CENTER, CW_USEDEFAULT, CW_USEDEFAULT,
500, 100, hWnd, (HMENU)IDC_INSTALLER_CHLD, hInst, NULL);

if (!hWnd)
{
return FALSE;
}

ShowWindow(hWnd, nCmdShow);
ShowWindow(ChildWnd, nCmdShow);
UpdateWindow(hWnd);
UpdateWindow(ChildWnd);

return TRUE;
}





The child window still isn't displaying!

Edit:

This is how I'd like the child window to be, without the image and the border:

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

Participate in the game development conversation and more when you create an account on GameDev.net!

Sign me up!