In X11 there are several situations where the keyboard can be 'captured' by a process resulting in key events not propagating to the window manager. Some examples are:
When a virtual machine has focus + keyboard capture
When Xephyr has keyboard capture
When the screen lock is active (not as important)
I'm interested in some kind of visual indication from my window manager for when a window is not only active, but is stealing focus from the WM as in some situations behavior is confusing.
Is this possible under X11? Sample code would be helpful so I can integrate it within my WM.
Related
I have an unusual exploratory test automation task, which relies on detecting keyboard input. (certain trigger words).
However, to automate the task, has proven very difficult, as the input must pass through the keyboard driver it seems. Thus, setting UI automation (like Sikuli, or even ghost mouse) to click on the on-screen keyboard, OR using Sikuli to 'type' or copy/paste text into any windows UI, is not registered.
Any ideas of how to emulate physical keyboard input for the purpose of automation?
You could use an Arduino to emulate a physical keyboard (there are easy to use libraries available). Also, if you use one of the more capable Arduino's with multiple serial ports you can send it what keypresses to emulate through the serial port. The computer will think it is a keyboard like any other. Except you can control it with software.
Of course, this solution assumes you can connect something to the USB port of the test computer.
ncurses app checks if terminal has been resized. If the size is less than 80x25, then blank the screen and show error message.
If the app has N windows, should all of them be removed with delwin(), or calling clear() would be enough? On the other hand, can already existing windows be later reused after clear() - to refresh and display contents if terminal size became satisfactory - or they should be recreated?
Clearing the windows sounds like the application's behavior rather than ncurses as such. The ncurses library (see resizeterm) will clear areas if the windows increase in size.
The best policy when resizing really depends on what you have inside the windows. ncurses is making reasonably safe changes, but since it has no information about your intention in making some things close on the screen, and others separated, all it can do is to attempt to resize windows so that their contents are preserved. The application can still clear them and start over again — as well as moving windows around on the screen.
It's your decision whether it is simpler to recreate the windows or reuse them.
As long as all of the rebuilding is done before the next repainting of the screen (e.g., with wrefresh), ncurses will make the updates with as little activity as it can.
I want to make Linux Os which run only one application as a full screen without showing any Login window at start up or title-bar and minimize/maximize/close button.
Is there any way to do this? It's Embedded platform and I already build Linux os for it and I also have application.
In the nutshell - X System is extremely flexible.
When you system starts up, it does the following steps:
Loads and runs the Kernel (and related initrd, if any, but it's irrelevant)
Starts init (process 1)
Starts system services, networking, etc.
Starts X server
Starts Window Manager (the application responsible for resizing windows etc)
Starts your application.
What you need to do, is to first disable GUI login and session (easiest to disable X) - you'll be able to log in through the console terminal (You can always access it with Ctrl-Alt-F1)
Then, launch something along the lines of
X &
DISPLAY=:0 ./yourapp.exe
If your app can handle making itself fullscreen, that would be it.
Add this to your startup scripts and you're there.
More explanation
The purpose of the Window Manager.. is to manage windows. It's that simple :)
Basically, there are 3 components of your typical X session.
X Server - the piece of software that provides an abstraction layer around the hardware (GPU drivers, Keyboard, Mouse, Touchscreen, etc). It has a concept of windows - areas where X Clients can draw into.
X Clients - Everything else. Your software, if it draws something, is likely one. So is the web browser, etc. The connect to the X Server, and draw.
Window Manager - A special type of an X Client, this piece of software provides the ability to control the windows on your screen. It often draws window decorations (minimize, maximize buttons), sometimes draws a taskbar, etc.
You are free to mix and match them entirely as you please. Simpler, minimalisting window managers, such as my ratpoison which I prefer for many prototype embedded systems only have the notion of fullscreen windows, and can switch between fullscreen apps (think Windows 8 Metro). Others draw window decorations, and allow overlapping and cascading windows.
Since developing a Window Manager is a simple and modular task, there are literally hundreds to chose from. You also can choose not to use one at all, at which point your windows have to self-manage (you'll not be able to move them around by default). Many applications respect the -geometry 1920x1080+0+0 parameter, telling them to open a window in 1920x1080 resolution at the 0,0 corner - effectively fullscreen.
I have a touch screen device that is running on windows CE. after 30 second the screen goes off to save power and will come back on it you touch it.
The problem is that randomly when the screen goes off the device will not come back on simply by touching the screen. I have a done a bunch of tests and there is no noticeable pattern to when this happens.
It appears to be performing the same action as when you press the suspend button from the main menu.
I have done some research and found there are 4 power saving settings in the registry and I think I need to disable one to stop the device from "suspending". I never want the device to turn off except for the screen going off, it is always connected to power.
Does anyone know how I can do this or why it is randomly suspending ?
And the entire device is in Chinese So really precise instructions would be appreciated. My application runs on top of the CE.
I know you're after precise instructions, but it's not that simple. The device OEM defined and implemented the power management system for the device, Microsoft only provided the structure for it. The OEM could have implemented power management in any way they sought fit,, and in fact they could have completely ignore the Microsoft-provided framework (wouldn't be the first time an OEM did that). Really you need to get a hold of the OEM and ask them how to prevent the behavior you're seeing or to get something different.
Barring that, you could always play around with the registry entries, but again, there's no guarantee any of them will work. You might look at adjusting power state or the activity timer registry entries.
Playing with the power manager control panel applet might also help (it's probably labelled 电源管理)
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\Timeouts]
"BattSuspend"=dword:0
I would like to write a simple C program that will perform different actions based on both "key down" and "key up" events. This program will be run from inside rxvt.
What library or mechanism should I use to access both key presses and releases? Is it true that reading /dev/tty will only provide key releases? Is this also true for termcap, terminfo, ncurses, and S-Lang? Is there a way to achieve this from within a terminal application?
The following links may be of some assistance in using the keyboard raw mode which will give you access to the keyboard events rather than just key releases.
This Linux Journal article
This article on SourceForge
And this HOWTO for when it all goes bad
Raw mode does have the disadvantage that you have to do your own conversion from scan codes to characters though.
This won't work in the general case. ANSI terminals (from which all emulators descend) represent key "press" events only. They don't record down/up events independently.
If you need low level keyboard event access, the proper environment is really a GUI program. Even a web application will have cleaner access to key events than a terminal.
I don't think ncurses will work. The link Basilevs provided talks about the "up arrow" key and the "down arrow" key, not a key press and release.