In the Win32 API (pure win32), The Menu bar does not occupy any area from the client area of the window. Which means the origin coordinates of the client area is right under the menu bar to the left.
When we create child window controls using CreateWindow (or any other method), that window takes some area of the client-area.
eg:- Creating a button which is at (xPos = 0, yPos = 0) and (width=width_of_client_area, height=20).
After creating the button if you'll use a GDI function like this, it'll be drew below the button:
Rectangle(hdc, 0,0, 200, 200);
But when creating a menu bar, it doesn't occupy client area. (GDI will not be drew under menu).
FINAL QUESTION:
How can i create a control on my parent window like the menu bar ?
The menu is rendered in the non-client area of the window, which is driven by a completely different set of window messages. Keep in mind that you don't actually create child windows for these types of controls. You will need to provide all the rendering and event handling for the customization you want to add. This means that if you want to add a button or checkbox you will need to implement it yourself. You can get your started with a handful of steps but there may be other things that need to be done depending on your requirements.
The first step is to process the WM_NCCALCSIZE message. This will allow you to adjust the size of the non-client area so that you have more space to draw the custom control. Basically you will pass this message on to the default window proc then modify the location and dimensions (just drop the top down X pixels) before returning.
The next step is to handle WM_NCPAINT message. Pass the message on to the default window proc then draw your custom visuals in the area you have reserved. You will be working with a window DC so you can draw to the entire window. It's important to keep this in mind so you don't destroy anything in the client area.
The last item that needs to be done is to handle mouse messages like WM_NCMOUSEMOVE. If the mouse event occurs outside the area where your control is located pass the message to the default window proc, otherwise handle the message yourself and skip the default proc. you will need to manage some state data for keeping track of when a button is down or not so as not to cause conflicts with the default window proc.
Keep in mind that when you want to draw directly to the non-client area you need to call GetWindowDC() instead of GetDC() to acquire a device context.
[Note: A good Google dance will be something like "WinAPI non-client area"]
Related
Since there is no way to deep customizing (a gradient background for example) win32 controls (such as buttons, menu items e.t.c) many people advise to create an own custom control.
And if I need a custom button I will use WM_MOUSEMOVE, WM_LBUTTONDOWN and a shadow buffer. I will draw all controls on the shadow buffer and then use BitBlt(hDC, ...) for my window.
But if I want to create a custom menu I must to foresee that menu can be drawn outside of the client area.
At first I need to mouse tracking outside of the client area. SetCapture(hWnd) seems to be a bad solution as it blocks mouse tracking for windows below.
Then I need to draw/erase items outside of my window. Erasing with InvalidateRect(NULL, NULL, TRUE/FALSE) seems to be a bad solution too as it cause of blinking.
What is the best approach to create custom menu with WinAPI?
Runtime menus that can appear anywhere on the screen can be shown with TrackPopupMenu() function. Create the menu with CreateMenu(), AppendMenu() etc, then show it with TrackPopupMenu().
First of all this is not MFC.
Here is a cropped version of the GUI I have been working on:
As you can see there is a bitmap image above the tab control (which uses the default window's handle), I will refer to it as "Blue Bitmap" I have no problems with it, it is functioning perfectly.
The problem I am having is setting another bitmap (from a bitmap file on disk) to the background of the child window (more specifically the tab control child window), replacing the grey colour. Here are some things I did to try and set the bitmap as the background for the child window (the tab).
1) I used the same method as was used to assign the blue bitmap to the window by first importing the bitmap using LoadImage like so:
index->hbmBitmapBanner = (HBITMAP)LoadImage(index->hInstance,L"Images\\horizontal.bmp",IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
Then in the WM_PAINT message:
case WM_PAINT:
{
PAINTSTRUCT ps1;
if (BeginPaint(WINDOWHANDLE,&ps1))
{
HDC hdcBanner = CreateCompatibleDC(ps1.hdc);
HBITMAP hbmOldHorizontal = (HBITMAP)SelectObject(hdcBanner,index->hbmBitmapBanner); // banner
BitBlt(ps1.hdc,0,0,516,101,hdcBanner,5,0,SRCCOPY);
SelectObject(hdcBanner,hbmOldHorizontal);
DeleteDC(hdcBanner);
EndPaint(WINDOWHANDLE,&ps1);
}
break;
}
That code was successful in setting blue bitmap to the window, but not in setting the other bitmap into the window, (with the blue bitmap's variables substituted into, size and orientation changed as well of course). It simply did not display the bitmap on the screen, and the window remained unchanged, yet no functions failed. ALSO, when I swapped the file locations around, it loaded the bitmap into where the blue bitmap was, so there is definitely no failure in the loading function.
2) Using the above code, I tried changing the first argument of BeginPaint to the window handle of the tab control box, this proved yet again of no use, and the window remained unchanged. I also tried changing the first argument of BeginPaint to a child window which is displayed on the information tab, this caused the child window (which is a groupbox) to disappear, yet still no bitmap appeared on the window.
3) As a last resort I stupidly attempted to use this function on the child window
SetClassLongPtr(tab->hTabIndex[0],GCLP_HBRBACKGROUND,(DWORD)GetStockObject(BLACK_BRUSH));
And of course, it didn't work
If it is of any use, here is how I created the tabbing in my window:
TCITEM tie = {0};
tab->hTab = CreateWindowEx(0,WC_TABCONTROL,L"",WS_CHILD | WS_VISIBLE,0,101,600,400,
WINDOWHANDLE,NULL,(HINSTANCE)GetWindowLong(WINDOWHANDLE,GWLP_HINSTANCE),NULL
);
Is the main tab control, followed by inserting individual the tabs (i.e the information tab)
TCHAR pszTab1 [] = L"Information"; // tab1's text
tie.pszText = pszTab1; // the tab's text/caption
TabCtrl_InsertItem(tab->hTab, 0, &tie); // insert the tab
Additional info: The tab control, and the windows are working/interacting perfectly apart from this. I was testing/attempting this for only one tab, because I knew if it worked on one tab, then it would work on all the tabs, hence saving time.
I have Programming For Windows Fifth Edition, by Charles Petzold beside me as reference, and there is a rather large section on bitmaps, but he doesn't go into talking about loading a bitmap to a child window, the closest he gets is using a bitmap in a menu, which is completely different than a window.
I think that the issue here is that Windows Common Controls do not interact with your application via your main thread's window procedure but via their own (system-defined) window procedures.
So, for example, when your tab window redraws itself, it does not do so in response to a WM_PAINT message arriving at the window procedure defined in your code. You should be able to verify for yourself that this is so by examining the window handles of messages passed to your window procedure, eg WM_PAINT.
If you wish to 'tap into' the default behaviour of a common control you have to 'subclass' it (see here) but in my experience attempting to change the re-draw behaviour is generally problematic.
In the case of a tab control the best thing to do is create an array of child windows sized to the client area of the tab control and arrange that the one displayed at any one time corresponds to the tab that is selected.
If you're using C++ you might consider creating a base class to wrap these windows in which the background (bitmap) drawing is handled. You can then derive a series of wrappers to handle each individual tab. I've used exactly this approach in the past and it works well.
It may be helpful to bear in mind that the tabs of the tab control do not extend over the whole of the control's client area but are just literally the tabs themselves. I don't remember the details but I think they are handled internally by the control and that manipulating them in any way is rather trick, even when the control is subclassed - may be wrong about that.
Hope that helps.
Cheers, Ian.
I'd like to make a captionless window that covers the entire desktop, but still shows the task bar. What is the best way to do this?
I can detect where the taskbar is and just resize my window to exclude it, but then I need to know when the user changes the size / position of the task bar.
Or, is there a combination of window styles or something else that will make sure my window is always behind the task bar?
Set your window placement using the return value from SystemParametersInfo, passing SPI_GETWORKAREA as a parameter.
Retrieves the size of the work area on the primary display monitor.
The work area is the portion of the screen not obscured by the system
taskbar or by application desktop toolbars. The pvParam parameter must
point to a RECT structure that receives the coordinates of the work
area, expressed in virtual screen coordinates.
Maximise a window with no caption/border.
I want to allow a user to drag my Win32 window around only inside the working area of the desktop. In other words, they shouldn't be able to have any part of the window extend outside the monitor(s) nor should the window overlap the taskbar.
I'd like to do it in a way that does cause any stuttering. Handling WM_MOVE messages and calling MoveWindow() to reposition the window if it goes off works, but I don't like the flickering effect that's caused by MoveWindow().
I also tried handling WM_MOVING which prevents the need to call MoveWindow() by altering the destination rectangle before the move actually happens. This resolves the flickering problem, but another issue I run into is that the cursor some times gets aways from the window when a drag occurs allowing the user to drag the window around while the cursor is not even inside the window.
How do I constrain my window without running into these issues?
Windows are, ultimately, positioned via the SetWindowPos API.
SetWindowPos starts by validating its parameters by sending the window being sized or moved a WM_WINDOWPOSCHANGING message, and then a WM_WINDOWPOSCHANGED message notifying the window proc of the changed size and/or position.
DefWindowProc handling of these messages is to, in turn, send WM_GETMINMAXINFO and then WM_SIZE or WM_MOVE messages.
Anyway, handle WM_WINDOWPOSCHANGING to filter both user, and code, based attempts to position a window out of bounds.
Keep in mind that users with multi-monitor setups may have a desktop that extends into negative x- and y-coordinates, or that is not rectangular. Also, some users use alternative window managers such as LiteStep, which implement virtual desktops by moving them off-screen; if you try to fight this, your application will break for these users.
You can do this by handling the WM_MOVING message and changing the RECT pointed to by the lParam.
lParam: Pointer to a RECT structure with the current position of the window, in screen coordinates. To change the position of the drag rectangle, an application must change the members of this structure.
you may also want to handle WM_ENTERSIZEMOVE to know when the window is beginning to move, and WM_EXITSIZEMOVE
WM_GETMINMAXINFO is what you seem to be looking for.
I want to create a Window like when a context menu pops up or clicking the menubar. I want a Window that will be like this and that I can take over its paint event. Sort of like what is created when you select a sub tool in Photoshop.
EDIT:I want to know how to create controls like the one that comes when you select a sub tool in Photoshop, these do not seem to have a parent window. Those little description popups are a good example of this type of window, and menu items, those rectangles have no parent window.
Thanks
EDIT2: see this: http://cdn-viper.demandvideo.com/media/CB3C805F-421E-45AE-8359-39D59D8F0165/jpeg/20412728-192C-462A-AF8E-1F30BA77AE05_2.jpg
You will notice the window for the sub tools, it is not constrained to a parent window.
But how do they get a nice shadow
around it, and how does it still stay
with the main window without a parent?
That's your real question.
There are several ways of getting the shadow. One is that the window is actually two windows, the "shadow" plus the "main" window.
When you create the flyout window (that's what it's called), you position it near the toolbar. If the toolbar gets a WM_MOVE message, it's your responsibility to call MoveWindow() on the flyout to keep it lined up.
Edited to add
The dwExStyle parameter of CreateWindowEx() should include WS_EX_LAYERED and probably WS_EX_TRANSPARENT, because the 'shadow' will use alpha blending. The hWndParent parameter is the application's main window. The x and y parameters must be calculated as an offset of whatever button the window is to be associated with.