How to write a program that runs another GUI program inside it - windows

I am not sure how to ask the question so here is a picture of some idea that came to mind
So for example, when you run my "custom launcher" it displays a window with a couple buttons on the side which you can assign values to. When you click on a button, the appropriate program will run in the big panel on the right (in window mode).
This is all from the user's perspective of course. They will just see that the program they want to run appears in that panel. The actual implementation may have nothing to do with "one program running inside another program"
My own use case is limited to windows desktop platforms only, but if it is possible to generalize it that would be nice as well.
Is this actually possible? Can I write such a program that will run another program inside a panel? The program that's launched may be someone else's, such as MS paint or calculator.

Just to expand on my comment above, here is an approach that may work for you: Fake it :)
When you launch the program, intercept all windows messages to the program that control it's position on screen. That way it 'appears' to be fixed in place, but in reality it's still attached to the normal Windows desktop.
Here's some light reading for you:
Windows Event Hooks
A hook is a mechanism by which an application can intercept events,
such as messages, mouse actions, and keystrokes. A function that
intercepts a particular type of event is known as a hook procedure. A
hook procedure can act on each event it receives, and then modify or
discard the event.

I would recommend against it in a commercial application because you are modifying the behavior of software you don't own - that software may make assumptions about what its parent window is, but for experimentation there's the SetParent Win32 function.

Related

Intercepting a window's attempt to steal global focus on Windows

I'm a developer and a long-time Windows user with an obsession about making my system as convenient to use as possible.
Yesterday I thought about something that has always annoyed me in Windows and that I've taken for granted, and I realized that I have a better idea for how it could work, and I'm now wondering whether it's possible to tweak Windows to work like that.
The thing that annoys me is when windows steal focus. For example, I could be running an installer for some program. While it's working, I'll switch to my browser and browse, maybe entering some text into an email in my browser. Then suddenly the installer finishes and its window steals the focus. Now I'm in the middle of writing an email, so I might press a key that happens to be bound to a button on that installer, and then that button gets invoked, doing some action that I never intended to happen!
This is doubly annoying to me because I'm using a multiple-desktop program called DexPot, and when a window steals focus, it also brings itself to the desktop I'm currently on, which can be really annoying, because then I have to put it back into its original desktop.
How my ideal solution to this problem would work: Every time a window tries to steal focus, we intercept that, and don't let it. We show something like a toaster message saying "Foobar installer wants focus, press Win-Whatever to switch to it". If and when you press the key combo, it switches to the window.
The question is: Is there an easy way to tweak Windows to make this happen? I know very little about Windows programming. I do know AHK and if it's possible with that, that'd be great.
No, there isn't an easy way to add this behavior, but Windows tries to do this automatically.
In theory apps shouldn't be able to steal the foreground while you're actively using another app. Unfortunatly there are some scenarios where Windows can't tell the difference between legitimate user actions that should change the foreground and unwanted foreground-theft. The window manager generally tightens up the holes a bit with each new version of Windows, but also needs to make sure that apps can come to the foreground when the user wants them to, even if that desire is expressed indirectly.
For example, a process launched by the current foreground process can put a window into the foreground. This is necessary so that when a user launches a window from Explorer the newly launched process can open its main window. This permission only lasts until the next user input, so if an application is slow to launch and you start working on an email the app may lose its foreground permissions before it can use them.
See the SetForegroundWindow function documentation for a list of requirements for a process to be able to set a window into the foreground.
There are also apps which specifically make use of these requirements to steal the permission (by joining the foreground queue or synthsising user input to themselves), but I suspect in your installer scenario it is accidental.
I'm not sure what exactly is going on, but I suspect that the problem comes from the installer running as a service and accidentally stealing the foreground permission when it tries to launch the app on your current desktop.
It would be theoretically possible for an external process to hook into the foreground system to override this and show your confirmation toast, but it would be tricky to get right and would require significant low level code (I'd probably start with a CbtHook). It would not be possible in a scripting package like AHK (assuming you mean AutoHotKey) but would need to be native C/C++ code injected into every running process.

Is it possible to call a function in a different, but currently executing process?

I have a friend who's working at a company that offers pretty poor support for its developers (scoring a 1/12 on the Joel Test).
Their build process is locked down pretty tight, and depending on the size of project it could take 40+(x2) mouse clicks to deploy. So I thought, "Hey, why not automate it the clicks using the win32api?" (Specifically using Python). I've got him a real nice tool that works just fine except for one issue - the tool that they use has a navigation pane that may or may not be open.
You can open and close it with a button press, but I'm not sure how I could make sure it was either open or closed. It's irrelevant to the build process - the only problem is that it alters where the mouse needs to click on the screen depending on its open status. The application is written in .NET and it exposes a function call that applications are able to use to toggle the panel, so I've been looking around for ideas and so far I've got two of them:
Attach to the process via a debugger and execute the function call somehow.
Take a screenshot at the location of the panels titlebar (which I've got through the win32 API and doesn't appear to change regardless if the panel is hidden or not).
Is there an easier way to figure out the state of this panel? The developers are given an admin account on their machine in addition to their regular account, so I can entertain ideas that require admin access, though I don't think that should be necessary?
UPDATE:
It looks like there's a button that can close the pane. In UIAVerify something shows up as "text" "Navigation" "btnClose". It says its AutomationId is btnClose but it's a ControlType.Text
What technology is this panel built from? Is it standard GDI or WPF? If its GDI, it should have a HWND. You should be able to find this HWND through either a class name or window title. Once you have the HWND, you can get its width.
If its built with WPF, er, I have no idea, but Snoop does this kind of thing, so I know its possible.

Window hooks and applications

Related to my question here, is it possible to create a window hook that will monitor if an application has been opened or not?
Most that I have found about hooks seem to focus on user input (keyboard press, mouse events), but I could not confirm if it is possible to know that the "double click" the user made is to open an application, or just to highlight a word.
Thank you.
Indeed, window hooks would not be sufficient. In fact for the task you are asking about you could use various strategies, such as:
enumerating the processes to find the one you're looking for (Tool Help API or PSAPI)
enumerating the top-level windows on the desktop (but you're limited to your desktop then)
check for a global or local event, mutex (or other kernel object) to deduce from that that some instance of the application is running
... or even from kernel PsSetCreateProcessNotifyRoutine
probably there are variations on the above plus some more.
In essence the question is whether you want to check for the process or for some other indicator that signifies whether the program you want to check for has been started.

Show a popup menu in another application's window

How can a Delphi XE application show a popup menu inside another application's window? The idea is for a helper-type app, running in the background. On a registered hotkey the application needs to display a popup menu near the text caret or mouse cursor.
Applications that do that are common, here's a menu created by AutoHotkey and displayed in a text editor:
I guess what I'm asking is: how can I display a popup menu at an arbitrary screen location, without it being attached to a Delphi control?
Create a TPopupMenu with the appropriate menu items. When you need to show it simply call Popup passing the top left position in screen coordinates.
PopupMenu1.Popup(X, Y);
#DavidHeffernan answered your question, but you might not have asked the right question.
Let's take the example you gave: the user is running some arbirary application, and you want to be able to detect a hotkey, display a menu, and then take some action based on the menu item chosen (and maybe even the user's context, such as the word under the cursor). This is more complicated than simply displaying a menu at arbitrary screen coordinates.
My recommendation is to use AutoHotKey instead of trying to replicate this in some other programming language. In case you're not aware of this, it is possible for your code to run AutoHotKey scripts. IIRC, you can compile AHK scripts, so you wouldn't need to install AHK, just the compiled scripts. AHK may not be the most elegant of solutions, but it has depth and maturity.
If this is not possible, then I suggest you research Windows Hooks and DLL Injection. Unless you can find some preexisting code or framework, this will entail quite a bit of work.
The reason for this complexity? To augment another program smoothly (without running into problems with focus, etc.) you want to have your code run as part of that other program. The mechanics of this can be done via DLL injection. However, that's only the first step. Once your code is running in the right context, then your code has to inter-operate with the "host" program. This can be tricky (it helps if you have deep experience with Windows messaging and the Windows API). If you want this to work smoothly with any arbitrary program, it gets even harder.

Create a Program that Sits in The Windows Taskbar and, When Activated, Stops the Screensaver From Starting

I don't really know where to begin. Let's start with the stupid questions:
What language should I use for this? What is suited for the task at hand?
Next, the real ones:
Is there a way to stop the screensaver from starting, short of changing the cursor position? If not, will changing the cursor position even work?
SetThreadExecutionState will prevent the screensaver from coming on or the machine from automatically going to sleep if you pass the ES_CONTINUOUS and ES_DISPLAY_REQUIRED flags.
I wrote an app awhile ago that does exactly what you are asking for. It runs as an icon in the System Tray, not the Taskbar, and uses a global message hook to disable the WM_SYSCOMMAND/SC_SCREENSAVE notification from reaching any applications. If that notification does not reach the DefWindowProc() function, the screen saver will never run.
Your program does not need to be visible in the task bar at all.
You don't even need a program at all, if you can disable the screensaver in the registry.
What you want to do can perhaps be achieved by sending a MOUSE_MOVE event to the desktop window. If you want to use C# (the only language I am current with right now), you can look at this article, but maybe a simple C program using the WinAPI is better suited for this task.
.NET will easily allow you to put an application in the system tray (checkout the NotifyIcon object in System.Windows.Forms.Controls).
I believe you can use the SetCursorPos (http://msdn.microsoft.com/en-us/library/ms648394(VS.85).aspx) API call to prevent the screen saver, just make sure you set them to the current location so you don't actually move the mouse.

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