Simulating a drag & drop operation using SendInput - winapi

Can SendInput be used to simulate a drap & drop operation?
I've got an application that accepts files of a certain format that are dropped on it, but not from the command line, and I want to associate it with a file. I thought I'd create a small tool that finds the window, and simulates a drag & drop of the file - is this at all possible? Do I need to use SendInput or possibly SendMessage? What would be the parameters?

Yes, pretty likely. SendInput injects mouse events at a very low level. SendMessage won't work.
You'll need a thread since DoDragDrop is a blocking call. Fake the mouse down first, start the thread, call DoDragDrop. The thread should sleep to give enough time for DoDragDrop to get started, then fake mouse move and mouse up. Keep fingers crossed that it works the first time, it is impossible to debug if it doesn't.

The shell already has a function that simulates a drop: SHDoDragDrop, no need for hacks like faking mouse input.
Since you are talking about the commandline, XP added support for simulating D&D for applications/registered file types: How do I accept files to be opened via IDropTarget instead of on the command line?

Related

Implementing a Custom Cocoa Event Tracking Loop

I'm working on a custom cross platform UI library that needs a synchronous "ShowPopup" method that shows a popup, runs an event loop until it's finished and automatically cancels when clicking outside the popup or pressing escape. Keyboard, mouse and scroll wheel events need to be dispatched to the popup but other events (paint, draw, timers etc...) need to be dispatched to their regular targets while the loop runs.
Edit: for clarification, by popup, I mean this kind of menu style popup window, not an alert/dialog etc...
On Windows I've implemented this fairly simply by calling GetMessage/DispatchMessage and filtering and dispatching messages as appropriate. Works fine.
I've much less experience with Cocoa/OS X however and finding the whole event loop/dispatch paradigm a bit confusing. I've seen the following article which explains how to implement a mouse tracking loop which is very similar to what I need:
http://stpeterandpaul.ca/tiger/documentation/Cocoa/Conceptual/EventOverview/HandlingMouseEvents/chapter_5_section_4.html
but... there's some things about this that concern me.
The linked article states: "the application’s main thread is unable to process any other requests during an event-tracking loop and timers might not fire". Might not? Why not, when not, how to make sure they do?
The docs for nextEventMatchingMask:untilDate:inMode:dequeue: states "events that do not match one of the specified event types are left in the queue.". That seems a little odd. Does this mean that if an event loop only asks for mouse events then any pressed keys will be processed once the loop finishes? That'd be weird.
Is it possible to peek at a message in the event queue without removing it. eg: the Windows version of my library uses this to close the popup when it's clicked outside, but leaves the click event in the queue so that clicking outside the popup on a another button doesn't require a second click.
I've read and re-read about run loop modes but still don't really get it. A good explanation of what these are for would be great.
Are there any other good examples of implementing an event loop for a popup. Even better would be pseudo-code for what the built in NSApplication run loop does.
Another way of putting all this... what's the Cocoa equivalent of Windows' PeekMessage(..., PM_REMOVE), PeekMessage(..., PM_NOREMOVE) and DispatchMessage().
Any help greatly appreciated.
What exactly is a "popup" as you're using the term? That term means different things in different GUI APIs. Is it just a modal dialog window?
Update for edits to question:
It seems you just want to implement a custom menu. Apple provides a sample project, CustomMenus, which illustrates that technique. It's a companion to one of the WWDC 2010 session videos, Session 145, "Key Event Handling in Cocoa Applications".
Depending on exactly what you need to achieve, you might want to use an NSAlert. Alternatively, you can use a custom window and just run it modally using the -runModalForWindow: method of NSApplication.
To meet your requirement of ending the modal session when the user clicks outside of the window, you could use a local event monitor. There's even an example of just such functionality in the (modern, current) Cocoa Event Handling Guide: Monitoring Events.
All of that said, here are (hopefully no longer relevant) answers to your specific questions:
The linked article states: "the application’s main thread is unable to process any other requests during an event-tracking loop and
timers might not fire". Might not? Why not, when not, how to make
sure they do?
Because timers are scheduled in a particular run loop mode or set of modes. See the answer to question 4, below. You would typically use the event-tracking mode when running an event-tracking loop, so timers which are not scheduled in that mode will not run.
You could use the default mode for your event-tracking loop, but it really isn't a good idea. It might cause unexpected re-entrancy.
Assuming your pop-up is similar to a modal window, you should probably use NSModalPanelRunLoopMode.
The docs for nextEventMatchingMask:untilDate:inMode:dequeue:
states "events that do not match one of the specified event types are
left in the queue.". That seems a little odd. Does this mean that if
an event loop only asks for mouse events then any pressed keys will be
processed once the loop finishes? That'd be weird.
Yes, that's what it means. It's up to you to prevent that weird outcome. If you were to read a version of the Cocoa Event Handling Guide from this decade, you'd find there's a section on how to deal with this. ;-P
Is it possible to peek at a message in the event queue without removing it. eg: the Windows version of my library uses this to close
the popup when it's clicked outside, but leaves the click event in the
queue so that clicking outside the popup on a another button doesn't
require a second click.
Yes. Did you notice the "dequeue:" parameter of nextEventMatchingMask:untilDate:inMode:dequeue:? If you pass NO for that, then the event is left in the queue.
I've read and re-read about run loop modes but still don't really get it. A good explanation of what these are for would be great.
It's hard to know what to tell you without knowing what you're confused about and how the Apple guide failed you.
Are you familiar with handling multiple asynchronous communication channels using a loop around select(), poll(), epoll(), or kevent()? It's kind of like that, but a bit more automated. Not only do you build a data structure which lists the input sources you want to monitor and what specific events on those input sources you're interested in, but each input source also has a callback associated with it. Running the run loop is like calling one of the above functions to wait for input but also, when input arrives, calling the callback associated with the source to handle that input. You can run a single turn of that loop, run it until a specific time, or even run it indefinitely.
With run loops, the input sources can be organized into sets. The sets are called "modes" and identified by name (i.e. a string). When you run a run loop, you specify which set of input sources it should monitor by specifying which mode it should run in. The other input sources are still known to the run loop, but just ignored temporarily.
The -nextEventMatchingMask:untilDate:inMode:dequeue: method is, more or less, running the thread's run loop internally. In addition to whatever input sources were already present in the run loop, it temporarily adds an input source to monitor events from the windowing system, including mouse and key events.
Are there any other good examples of implementing an event loop for a popup. Even better would be pseudo-code for what the built in
NSApplication run loop does.
There's old Apple sample code, which is actually their implementation of GLUT. It provides a subclass of NSApplication and overrides the -run method. When you strip away some stuff that's only relevant for application start-up or GLUT, it's pretty simple. It's just a loop around -nextEventMatchingMask:... and -sendEvent:.

Multiple cursor on windows application

I have founds some resource like this dealing with the subject of attaining multiple cursors on windows for more than one mouse attached to the system. My requirement is a little simpler but I need some inputs on it.
1) What I want is to invoke an application (lets say IE) and do mouse activity(hovering , clicking etc) on it. All of this while there should be no disturbance to the system cursor , which should be free to be used by the user of the desktop.
2)I understand that this can not be done using the windows cursor apis as the documentation always mentions "the cursor" and there is no concept of multiple cursors inbuilt.
3)
This leaves me to drawing a cursor on the target window. A bitmap perhaps and to move it randomly? What APIs will be of use here?
How do I simulate the visual effects that are actually done my actual cursor movement. Do I need to send messages to the target
window like WM_MOUSEMOVE , WM_SETCURSOR etc.?
Does sending mouse messages to the other window interfere with the mouse activities that the user is involved in currently? The
intention is not to disturb the user while the application runs.
Thanks for your inputs.
Create a separate window for each extra mouse that is installed, and put an image of the desired cursor in each window. Then use the Raw Input API to monitor activity on the extra mouses and move your windows around as needed, and use mouse_event() or SendInput() to send out your own mouse events (movements, clicks, etc) as needed.

SIGWINCH equivalent on Windows?

This could very well be another silly question, but I can't seem to find the answer (or any for that matter), so here goes.
I have a command line program that uses SIGWINCH on Linux to detect the window size change, and I apparently have a user who is using the program on Windows. The problem, is that the program uses SIGWINCH to detect changes in the window size and this signal is unsupported on Windows. I've tried Googling for every combination of search terms I can think of, but due to the relationship between SIGWINCH and changes in the size of the window, I'm having trouble finding any useful results. I'm looking for a Windows equivalent, or the method most often used to detect changes in the window size on Windows computers.
How do you detect changes in window size on Windows?
Since I don't think you can subclass console windows (and thus catch WM_SIZE messages), you may just have to poll GetConsoleScreenBufferInfo.
EDIT: Upon further investigation (not tested!), it might also be doable without polling using ReadConsoleInput. Summary: Call SetConsoleMode to turn on window input events. From a different thread, wait for the console input handle to become signaled using WaitForSingleObject or a similar function. Read all pending console events; the presence of window buffer size events means something's resized your console window.

Can AppleScript read mouse position / action in one application and replicate it in another application?

I've been searching for a mouse broadcaster for Mac for a while and it seems there are no solutions for doing this, so I must look for alternative solutions now. I'm wondering if AppleScript is capable of performing such a task. Basically, what I would like to do is read mouse position and action when performed in one application for as long as the script is active, and broadcast/replicate it in one or more other applications. Is AppleScript capable of this?
Just to clarify, I'd need to simulate mouse movement in the other applications... for example, if I opened up several instances of a drawing program, assuming that the program had the same resolution, anything I drew in the main program, would replicate on the other programs.
Really applescript cannot do what you need. It's not made for that. Applescript is made to run the commands in an application's applescript dictionary. I assume that the dictionary of the applications you want to control give you no way to read and control the mouse.
You do have an applescript alternative though. I have made a command line tool to read the mouse position and also to move the mouse. So theoretically you can do what you want with applescript and my tool. I do not believe you will get the results you expect though. Anyway you can try. Here's a link to the web page for my tool. I hope it helps.
Get it here.
Your basic approach could be 1) activate the application you want to read the mouse position, 2) run my tool in a repeat loop and record the mouse positions, 3) activate the second application that you want to duplicate the mouse movements, 4) use a repeat loop with my tool to make the mouse move according to how you recorded it.

How can I fire a key press or mouse click event without touching any input device at system level?

How can I fire an automatic key press or mouse click event when a color appears on the screen
on other application or browser?
It depends a lot on what you want. Do you want to send the keys to
your Application
another fixed Application
Simulate a global keypress
Simulating keys globally
All of these will cause problems targeting a specific application and the active window changes.
SendKeys Sends Messages to the active app. It's a high level function taking a string which encodes a sequence of keys.
keybd_event is very low level and injects a global keypress. In most cases SendKeys is easier to use.
mouse_event simulates mouse input.
SendInput supersedes these functions. It's more flexible but a bit harder to use.
Sending to a specific window
When working with a fixed target window, sending it messages can work depending on how the window works. But since this doesn't update all states it might not always work. But you don't have a race condition with changing window focus, which is worth a lot.
WM_CHAR sends a character in the basic multilingual plane (16 bit)
WM_UNICHAR sends a character supporting the whole unicode range
WM_KEYDOWN and WM_KEYUP Sends keys which will be translated to characters by the keyboard layout.
My recommendation is when targeting a specific window/application try using messages first, and only if that fails try one of the lower level solutions.
when a color appears on the screen on other application or browser
I made one program using OpenCV and C++ for operating mouse with finger gesture. I used 3 color strips for 3 mouse function.
Yellow color for Left click
Blue color for Right click
Pink color for controlling cursor position
Whenever camera detect these colors, associated function takes place, I have used mouse_event for performing mouse function.
For more information you may read my code, blog, video.
I'm not 100% sure what you want, but if all you are after is running the method linked the the button.Clicked event, then you can manually run the method just like any other method.
You can use the .NET SendKeys class to send keystrokes.
Emulating mouse clicks requires P/Invoke.
I don't know how to detect colors on the screen.

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