As the title says, do GUI applications (written for example in Java using Swing or in C++ using Qt...) handle mouse signals (click, right-click, motion...) directly from the mouse device or they receive signals from the operating system ?
It's a very general question. What do you have in mind with it?
Very general, I would say: "it depends" - at least on the operating system, your app runs on and your mouse is connected to.
In all modern OSes, there's an abstraction layer (far away from any real circuits inside the computers hardware) that would make the answer to your question: they get the signals from the OS.
Related
I bought a new mouse (which doesn't have it's own software) and I was wondering:
Since it has RGB lights that change on their own, as far as my understanding goes, it has some software inside it that controls this.
First, the simpler question: when I first connect the mouse, Windows says it's "installing" some stuff. Where can I find this stuff (files probably)?
Second: Is there any way for me to "reverse engineer" this and get access to the mouse's code, so that I would be able to control the LED's color, for example?
When Windows says it is "installing" something for your mouse, it is looking at the USB descriptors, figuring out what driver to associate with the mouse, and recording other metadata. You can look in your registry under "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB" to see what gets recorded. For a more complicated device, I think Windows could actually download driver files from the internet during this stage and install them on your computer. But for a standard HID mouse, it should already have the drivers it needs.
There is no standard way to read the code from a hardware device, and it is likely to be extremely difficult if the device is not open source. The code is likely stored in the memory of a microcontroller that has read protection enabled, meaning that it cannot be read from an external programmer. It is also possible that much of the funcitonality of the mouse is actually implemented in application-specific hardware instead of software.
If there is existing software on your PC that allows you to control the LED color of your mouse, your best hope is to run that software and look at what USB packets it is sending to the mouse using a USB protocol analyzer.
I am looking for a wireless communication technology for exchanging data between devices via sound in ultrasonic frequencies.It is possible to communicate with two mobile devices.I want to communicate a mobile and an embedded device.Is it possible?Any device is working with this protocol?
Of course it is possible. Back in the 1970's my TV remote control used ultrasound to change the channel and turn the TV off. The control was somewhat rudimentary IIRC a short press changed the channel up and a long press turned the TV off. It worked quite reliably for these functions.
Providing more functionality would require a more complicated modulation scheme which, as has been said in another answer, would be prone to interference from other sound sources. This probably explains why infra-red communucation signals are used in more modern remote control systems.
It is possible - why shouldn't it be? Smartphones are just embedded computers too. I imagine getting CE/FCC/etc certifications with such an embedded device will not be so easy. And production testing ...
But is it feasible? Probably not. Power consumption is a lot higher than with any RF-link, it's more susceptible to noise (quite literally) and the required components (microphone+speaker) are bigger than RF-components (antenna).
And then there's a whole bunch of other things you need to keep in mind when working with ultrasound, starting with the plastic design of the embedded device. But also things like the effect of ultrasound on people and their pets etc.
I have heared vulkan will unify the initialisation on different operating systems. Does that mean vulkan creates the window, handles mouse/keyboard events so I can avoid using os specific programming?
It won't. Window creation will be platform specific and an WSI extension will let you link the window to a renderable Image that you can push to the screen.
From information gleaned out of the presentations that have been given I expect that you will use a platform specific WSI Extension to create a Swapchain for your window.
Then each time you wish to push a frame to the screen you need to acquire a presentable image from the swapchain; render to it and then present it.
see this slide pack from slide 109 onward.
No, Vulkan is a low-level API for accessing GPUs. It does not deal with windows and input. In fact it can be used easily in a "headless" manner with no visual output at all.
Porbably not, Vulkan API is an Graphics Library much like OpenGL.
Where in Linux Ubuntu OpenGL is used for animation effects of the desktop in Unity and could be replaced with Vulkan for better performance.
But I don't think Windows will change it as they have their own DirectX Graphics Library and would be weird if they use something else instead their own software.
The most applications that are going to benefit from Vulkan are Games and other software that uses either 2D or 3D rendering.
It's very likely that most of the games are going to change to Vulkan because it's Cross-platform and therefore they will gain more users which equals to more profit.
Khronos (Vulkan API developers) are also bringing out tools that will largely port your application from OpenGL or DX12 to Vulkan therefore requiring less development/porting from the software developers side.
So...
Window creation, likely. (Although the code behind the window is CPU side, the library that draws the window on screen might be using Vulkan) - this differs greatly from which OS, distribution and version you are working on.
Mouse/keyboard events, no as this doesn't require any graphical calculations but CPU calculations.
Window (frames) are general desktop manager controls; you could display the vulkan app's content in the client area, otherwise vulkan would have to provide interfaces to the desktop manager for window creation (GUI library). Someone could simply create a device context (DC in windows, similar for the X server) then manage the "vulkan app" manually like a windowed game with no chrome (frameless), but this would be a great deal of work right now.
Old hand Windows developer bible addressing device context and rendering among many other things: Programming Windows®, Fifth Edition (Developer Reference) 5th Edition. Very good read and from an agnostic point of view provides a great deal of carry over knowledge loosely applicable to most systems.
Is it possible to program a wireless adapter attached to a computer?
I need to modify how they work, not just using them to perform a task such as scanning or connecting.
I have already tried the Native Wifi API, but that library is too high level. I cannot modify how exactly the wireless adapter works.
Any solution in any programming language in any operating system is very welcomed. (Sounds so desperate lol)
You need an open-source operating system then. Hardware varies in how programmable it is, but for example, Atheros wireless cards do not have an on-board processor, and therefore they do the absolute minimum of the 802.11 protocol in hardware, leaving everything else to the device driver. More info in these places: http://linuxwireless.org/ http://git.kernel.org/?p=linux/kernel/git/linville/wireless-testing.git;a=summary;
If you really need to go further that what commodity hardware can do, look in to GNU Radio and the USRP/USRP2: http://gnuradio.org/redmine/wiki/gnuradio
And yes, you do have to be careful about the legal implications of this stuff, but then if you don't turn off the regulatory framework, there is software to help with that.
Generally speaking, the manufacturer will attempt to prevent you from doing this. Since what you're working with is really a radio transceiver, its operation is regulated. In the US, for example, such things fall under the purview of the FCC. Depending on the country, changing how it operates (and then operating it) is likely to be illegal.
If you have an atheros chipset on your WLAN card then load up linux and install ath5k/ath9k or madwifi and you can do some interesting things with the driver.
I had a look at this and this but no one sounded particularly sure of their ideas and I'm kind of after a different thing anyway. I want to hook my usb power cables (red and black) up to my phone so I don't have to use a battery (the battery is dead anyway and this is just an experiment). The problem is that USB standards ensure that a minimum of 4.35V is supplied, when I only want 3.7V. Does anyone know for sure that you can or cannot regulate power output programmatically? Some other queries I have are: What kind of power does the sleep mode provide? And what would I need to code something in to play with this, C++?
No, you won't find a computer that allows you to set this voltage in software. It would break the USB specification.
You can get 150mA by default, and 500mA if your USB device negotiates it with the computer (requiring a little bit of logic in the device). Multiply by 5V to get the provided power.
A bit more info on the answer from Pascal:
The normal operation (Non-Configured mode) is 100mA
In theory, the operating system should check the MaxPower value of the device's configuration descriptor to decide if to allow it to draw more than 100mA.
In practice, PCs do not do it (and have no way to control it). So you can try taking 500mA.
(Of course connecting a bus powered hub and linking more then one 500mA device, should, not work.)
If the device is not actively used, the OS may (and should) suspend it. When suspended the power is limited to 1-0.5mA (Again, in theory, since it can not be controlled by software).