I'm working on a C application using Gtk for the GUI. We have custom slider widgets connected to the "mouse scrolled" event with a callback function. The problem is each scrolling increment will trigger the callback once, which updates a parameter and refreshes a computationaly-expensive rendering. So, when the user scrolls more than once, the GUI freezes until all scrolls are processed individually in sequence.
I want to have the multiple unit scrolling increments recorded as one flat increment, such that the expensive rendering is started only once the user is done scrolling, so we only record all increments until the scrolling is finished and then we update the parameter and refresh the rendering.
My first idea was to have the "mouse scrolled" callback emit some "update" signal and save :
the timestamp of the scroll event long t,
the number of scrolling increments int steps
Each new scrolling event would increment the steps counter and overwrite the timestamp.
Then, the "update" signal would be captured by a function that would wait for t + 0.5 s to actually save the slider value and trigger a new rendering. If the user performs a new scrolling during that time, the function would just keep waiting.
Is there a Gtk or C API to perform that kind of task ?
Related
Using redux-toolkit, rxjs, redux-observable
I want to add a 1-second delay between the same action if they are within a short period of time.
A naive example:
if you click a button that displays a pop-up 10 times really quickly, then I want to only show all ten pop-ups but only one pop-up for a second before showing the next pop-up.
let's say the button dispatches an action. is there a way to observe the stream of actions coming in and add a delay?
I'd like derive a class from Button to add an initial delay and interval which shall be used as long as the button is touched for repeated action.
At first thought this seems to be simple enough but the method com.codename1.ui.Button.setState(int) cannot be overridden because it has package access only. Is that for a good reason?
I noticed, that Button calls actionPerformed on pointerReleased. My Button descendant should call actionPerformed repeatedly but not wen the parent container of the Button is beeing scrolled. This would hopefully just correspond with the Button state STATE_PRESSED, right?
If I understand correctly what you mean then I'd just start a timer on the pressed method and then repeatedly call super.pressed & super.released whenever the timer elapses.
I am working on a windows store application and I want to be able to drag between buttons so that the originally pressed button becomes deactivated and the newly "dragged onto" button becomes activated but I can't seem to get this to work.
I have 2 Buttons inside a StackPanel and the events I have on them are:
PointerPressed
PointerEntered
PointerReleased
PointerExited
PointerCanceled
PointerCaptureLost
PointerPressed and PointerEntered share the same event handler and the rest (the "deactivation" events) share the same event handler.
If I press one button my "activated" event handler is triggered and if I drag off it my "deactivated" event handler is triggered but if I then drag onto the second button the "activated" event handler isn't triggered again.
Strangely, if I start by dragging from off the StackPanel onto one of the buttons the "activated" event handler is triggered. I assume that it is something to do with the internal pointer management stuff but can't seem to find a workaround.
Does anyone know why this is happening and how I can get it to work how I want?
Thanks for your time.
Edit
Okay I've been researching some stuff and I've come across CapturePointer() and ReleasePointerCapture() but this seems to be broken - If I capture the pointer, when I take my finger off the screen, PointerReleased doesn't even get hit.
I've also realized why the "dragging from off the SP onto one of the buttons causes it to 'activate'" - this is because when a button is pressed it doesn't route its event but fires a Click event - meaning the same pointer cannot fire a PointerEntered event of another button, but if it starts outside a Button it will trigger PointerEntered.
This doesn't get me much further but it is a little extra info :)
The concept of Button is a bit unique in regard to mouse capture and how dragging away from it happens. In your scenario I'm not sure if the event model around Button will work correctly for you. On Button, when a pointer is depressed (mouse) it has capture until it is released. This is not the same for touch where a press and drag away is different because in touch there isn't any explicit capture unless you create it.
So what you are hitting is going to be a slight conflict between mouse/touch interactions anyway using Button -- using some other UI element (not sure if you have a styled button) should get you what you want.
I have a slideshow application where i want to wait a certain amount of seconds, then show my front page, then wait again, then show next page, and so on. My problem is that when i use Thread.Sleep in between, the UI arent updated, it just sits there waiting and i only see my last control (after the full amount of time has passed (i.e all the sleeps). Any solutions for doing this?
Thread.Sleep(1000);
ChangeContent(new FrontPage());
Thread.Sleep(5000);
ChangeContent(new HtmlPage());
Pre WPF i would just use the Application.DoEvents.
Use a DispatcherTimer.
I have a button which launches a "modal dialog" - it just creates a transparent grid covering everything, with the "dialog" created on top of that.
However I have a strange issue - if I double/triple click the button really fast (or add some delay in the event code), the button click event is executed multiple times, creating multiple overlapping modal dialogs. If the first action in my event is to disable the button (IsEnabled=false) it seems to prevent this.
My guess is that Silverlight is being multithreaded with input - it is not only recording the second click in another thread (while the button's click event is running), but it is jumping the gun by evaluating which control should be the target before the previous event has finished executing. Even though that event alters what control is at those mouse coordinates, it doesn't matter.
Does anyone know anything about this behavoir, or a way around it? If I have something like a save window, where the user clicks a save button, a blocking grid ("Saving...") is placed up while it saves, and then the whole "window" is closed, I'd like to avoid the user being able to queue up multiple save event clicks (this could lead to unpredictable program behavoir).
If you've ever worked with WinForms or WPF, this is expected behavior. Your button is broadcasting its Click event until your modal dialog covers it up. Unfortunately, there is some amount of time between your first click and when the modal dialog covers the button which allows multiple clicks to the original button.
You have two solution choices:
Disable the button after the first click and then re-enable after the modal dialog returns. You've already mentioned that this works.
Write code in the Event Handler of the button to determine if a modal dialog is already being displayed. This way, you're putting the responsibility in one location rather than splitting it up (disabling and re-enabling the button). This would be my preferred solution.
I think what you're seeing is the behaviour of Silverlight's routed events.
You can set the Handled property of the event arguments to true to prevent the event from bubbling.