Function to retrieve the size of an element - c++

What I need is a function to retrieve the size of an element, be it a Java Applet window in a browser, text boxes in programs, applications window and so on.
Now I don't know what this kind of function is called, but I uploaded an example from an application that had that functionality.
Example (The red box)
What I need to be able to with this is get its size and its coordinates on the screen. This needs to be in C++.
So ff anyone could give an example, or atleast the name of that kind of function, I would be grateful.
I found a program that has the function I seek: It is called Scar Divi, which is a scriptable tool to perform repetitive actions, mostly uses for cheating in a game called Runescape it seems. Unfortunately it is closed source.

Are you looking for Window Geometry or desktop widget?

After getting an image of the screen (there will be somethign in Qt to do this)
You need an image processing library like openCV to find the rectangle - look for "Hough Transform"

I found the solution!
POINT p;
HWND wnd;
RECT rec;
GetCursorPos(&p);
wnd = WindowFromPoint(p);
GetWindowRect(wnd, &rec);
This will give you the coordinates for the box (extract from rec).

Related

How to get IWebBrowser2's update rect?

I am using IWebBrowser2 control to convert html into a bitmap in a win32 program, which I have succeeded doing it. I Draw the whole page all the time, which is not efficient way to do.
So it will be very good to know the update area, so that each time I can only draw the update rect. But I have not found any way to do so.
I did rendering flash before, and I can get dirty rect from IOleInPlaceSiteWindowless::InvalidateRect(LPCRECT pRect, BOOL), while IWebBrowser does have a window and does not have this interface.
What to do to get the dirty rect? Thank you inadvance!!
I think GetUpdateRgn is the function you are looking for. It returns the currently invalidate region.

How do I determine if a window is off-screen?

In Windows XP and above, given a window handle (HWND), how can I tell if the window position and size leaves the window irretrievably off screen? For example, if the title bar is available to the cursor, then the window can be dragged back on screen. I need to discover if the window is in fact visible or at least available to the user. I guess I also need to know how to detect and respond to resolution changes and how to deal with multiple monitors. This seems like a fairly big deal. I'm using C++ and the regular SDK, so please limit your answers to that platform rather than invoking C# or similar.
Windows makes it relatively simple to determine the size of a user's working area on the primary monitor (i.e., the area of the screen not obscured by the taskbar). Call the SystemParametersInfo function and specify the SPI_GETWORKAREA flag for the first parameter (uiAction). The pvParam parameter should point to a RECT structure that will receive the coordinates of the working area in virtual screen coordinates.
Once you've got the coordinates that describe the working area, it's a simple matter of comparing those to the current position of your application's window to determine if it lies within those bounds.
The desire to support multiple monitors makes things slightly more complicated. The documentation for SystemParametersInfo suggests that you need to call the GetMonitorInfo function instead to get the working area of a monitor other than the primary. It fills in a structure called MONITORINFOEX that contains the member rcWork that defines the working area of that monitor, again expressed in virtual screen coordinates as a RECT structure.
To do this right, you'll need to enumerate all of the monitors a user has connected to the system and retrieve the working area of each using GetMonitorInfo.
There are a few samples of this to be found around the Internet:
MSDN has some sample code for Positioning Objects on a Multiple Display Setup.
If you're using MFC, here's what looks to be an excellent example of multiple monitor support.
Even if you're not using MFC, that article refers the following link which looks be a real gem as far as explaining how multiple monitor supports works in Windows, even if it's a little bit old school. Like it or not, very little of this has changed in later versions of Windows.
Finally, you mentioned wanting to detect resolution changes. This is much simpler than you probably imagined. As you know if you've done any Windows programming, the primary way that the operating system communicates with your application is by sending messages to your WindowProc function.
In this case, you'll want to watch for the WM_DISPLAYCHANGE message, which is sent to all windows when the display resolution has changed. The wParam contains the new image depth in bits per pixel; the low-order word of the lParam specifies the horizontal resolution and the high-order word of the lParam specifies the vertical resolution of the screen.
You can use MonitorFromRect or MonitorFromPoint to check if window's top left point or bottom right point isn't contained within any display monitor (off screen).
POINT p;
p.x = x;
p.y = y;
HMONITOR hMon = MonitorFromPoint(p, MONITOR_DEFAULTTONULL);
if (hMon == NULL) {
// point is off screen
}
Visibility check is really easy.
RECT rtDesktop, rtView;
GetWindowRect( GetDesktopWindow(), &rtDesktop );
GetWindowRect( m_hWnd, &rtView );
HRGN rgn = CreateRectRgn( rtDesktop.left, rtDesktop.top, rtDesktop.right, rtDesktop.bottom );
BOOL viewIsVisible = RectInRegion( rgn, &rtView );
DeleteObject(rgn);
You don't have to use RectInRegion, I used for shorten code.
Display, resolution change monitoring is also easy if you handle WM_SETTINGCHANGE message.
http://msdn.microsoft.com/en-us/library/ms725497(v=vs.85).aspx
UPDATE
As #Cody Gray noted, I think WM_DISPLAYCHANGE is more appropriate than WM_SETTINGCHANGE. But MFC 9.0 library make use of WM_SETTINGCHANGE.

Custom draw button using uxtheme.dll

I have implemented my custom button inheriting from CButton and drawing it by using uxtheme.dll (DrawThemeBackground with BP_PUSHBUTTON).
Everything works fine but I have two statuses (Normal and Pressed) which Hot status is the same. It means when the user places the cursor over the button it is drawn alike regardless the button status (Pressed or not).
This is a bit confusing to the user and I would like to change the way the button is drawn in Pressed & Hot status. Does anybody know a way?
I have also thought about custumizing the whole drawing but the buttons use gradients, borders, shadows, etc. So it is not easy to achive the same look&feel drawing everything by myself. Is there a way to find the source code of the dll or know how to do it?
Thanks in advance.
Javier
Note: I think I could be able to achive what I want to do by using CMFCButton and overriding the OnDraw method. Let the control draw the button on OnDrawBorder and then drawing the inside button myself. But I need to know how the control draws the inside button when pressed. It is a gradient and I can't guess how it's done. Does anybody have a clue?
In answer to your second question, if you derive from CMFCButton instead of CButton you can override OnDraw() or OnDrawText() instead of the usual DrawItem(). That way the default button background will be drawn, and then your drawing code is executed.
The only way I know of to really tackle this is to use 'custom draw', rather than 'owner draw'. Custom draw came in with Windows 2000, but is only used by button controls with comctrl32 6.0 (so Windows XP onwards), isn't very clearly documented, and isn't something MFC goes out of its way to support.
Anyway, the good thing about custom draw is that it lets you hook in at various points in the drawing process, unlike owner draw, which makes you deal with the whole thing. Have a look in MSDN at the NM_CUSTOMDRAW notification message.
For the other part of your problem, detecting the 'hot' state, the easiest way to do this is to use WM_MOUSEMOVE messages and the TrackMouseEvent() function to track whether the mouse is over your button.
Unfortunately this is a bit of a vague answer: the amount of code you need to demonstrate a button that uses custom draw is a bit too much to type into these answer boxes! I do have a project that demonstrates such techniques, using a custom draw button (falling back to owner draw on older Windows versions) that adds a little arrow to the button. You can have a look at the source code by getting
Windows_UI_source.zip
Open it and have a look at the "DropArrowButton" class. The important bit is the OnCustomDraw() handler and its helper function DrawControl(): these get called at the various button drawing phases, and use UxTheme to draw the control appropriately.
I finally figured out how to achive what I want to do. It's pretty easy indeed.
I use two calls to DrawThemeBackground. The first one with PBS_PRESSED and the second one with state PBS_HOT. Then I make a ExcludeClipRect to avoid from drawing over the center of the button.
Something like this:
DrawThemeBackground( hTheme,
pCustomDraw->hdc,
BP_PUSHBUTTON,
PBS_PRESSED,
&pCustomDraw->rc,
NULL);
CDC *pDC = CDC::FromHandle(pCustomDraw->hdc);
CRect rectClient;
GetClientRect(rectClient);
CRect rectInternal = rectClient;
rectInternal.DeflateRect(4,4);
pDC->SelectClipRgn(NULL);
pDC->ExcludeClipRect(&rectInternal);
DrawThemeBackground( hTheme,
pCustomDraw->hdc,
BP_PUSHBUTTON,
PBS_HOT,
&pCustomDraw->rc,
NULL);
pDC->SelectClipRgn(NULL);
Of course this is not the whole code but I think is enough to make my point.
Thanks.

Get resolution of DirectX device

Where should I be looking for resolution of DirectX (3D) device? getViewport seems to have Width and Height, yet as far as I know viewport is supposed to be an area, not 2D "canvas" with these attributes.
(I hope "resolution" applies to the device, not D3D directly. Please correct me if this part is wrong.)
Simple MSDN link will be good answer as well, however I already browsed it through and couldn't find it.
Edit: it seems like getDisplayMode will work for fullscreen apps that changes resolution since it returns the display adapter mode, yet I'd like to be able to get the size of d3d window too.
DirectX doesn't actually own a window. If you remember when you initialise the device, you give it a handle to a window. It takes this and displays to its viewports within this window.
So if your looking specifically for the window size then you'll want to get it at the OS level.
This question discusses how to deal with it.
Namely GetWindowRect/GetClientRect(HWND, LPRECT)
If for some reason you only have the d3d interface, you can use getcreationparameters to get the original hwnd and then you can use GetWindowRect or GetClientRect as suggested before.
D3DDEVICE_CREATION_PARAMETERS cparams;
RECT rect;
device->GetCreationParameters(&cparams);
GetWindowRect(cparams.hFocusWindow, &rect);
//rect.width
//rect.height
Perhaps this is what you need: IDirect3D9::GetAdapterDisplayMode Method
http://msdn.microsoft.com/en-us/library/bb174316%28v=VS.85%29.aspx
If you want the window size then call "GetClientRect" on the hWnd you are setting up with.

How to draw text on the desktop in Windows?

How Would I go about placing text on the windows desktop? I've been told that GetDesktopWindow() is what I need but I need an example.
I'm assuming your ultimate goal is displaying some sort of status information on the desktop.
You will have to do either:
Inject a DLL into Explorer's process and subclass the desktop window (the SysListView32 at the bottom of the Progman window's hierarchy) to paint your text directly onto it.
Create a nonactivatable window whose background is painted using PaintDesktop and paint your text on it.
First solution is the most intrusive, and quite hard to code, so I would not recommend it.
Second solution allows the most flexibility. No "undocumented" or reliance on a specific implementation of Explorer, or even of just having Explorer as a shell.
In order to prevent a window from being brought to the top when clicked, you can use the extended window style WS_EX_NOACTIVATE on Windows 2000 and up. On downlevel systems, you can handle the WM_MOUSEACTIVATE message and return MA_NOACTIVATE.
You can get away with the PaintDesktop call if you need true transparency by using layered windows, but the concept stays the same. I wrote another answer detailing how to properly do layered windows with alpha using GDI+.
Why not just draw the text in the desktop wallpaper image file?
This solution would be feasible if you don't have to update the information too often and if you have a wallpaper image.
One can easily use CImage class to load the wallpaper image, CImage::GetDC() to obtain a device context to draw into, then save the new image, and finally update the desktop wallpaper to the new image.
i haven't tried but i assume you could do the following:
use GetDesktopWindow to retrieve the handle of the desktop window
use SetWindowLong to point the windows message handler to your own procedure
in your proc, process the WM_PAINT message (or whatever) and draw what you need.
in your proc, call the original message handler (as returned by SetWindowLong).
not 100% sure it will work, but seems like it should as this is the normal way to subclass a window.
-don
If your intent is to produce something like the Sidebar, you probably just want to create one or more layered windows. That will also allow you to process mouse clicks and other normal sources of input, and if you supply the alpha channel information, Windows will make sure that your window is drawn properly at all times. If you don't want the window to be interactive, use appropriate styles (such as WS_EX_NOACTIVATE) like Koro suggests.