How to find when GtkWidget was validated in Gtk+2 - gtk

I need to know when a GtkWidget was redrawn and validated after I change it's content (schedule a redraw).
Is anyway to get whether it's redrawn complete or need to wait more to get redrawn.

The way to get around what you need is to delay the scroll until GTK knowns how big the scroll area is. Probably the easiest way is to use g_idle_add(). Call-backs added to it will be executed in priority order when there are no other tasks needed to be done. GTK does use the idle functions at a high priority to do its redraws, but a default priority should be OK for you.
gboolena my_delayed_function(gpointer user_data)
{
// The function that does the scroll goes here.
return FALSE;
}
void my_function_that_shows_something()
{
// Do some drawing.
// ...
// Schedule a scroll.
g_idle_add(my_delayed_function, NULL);
}
As a note you must return FALSE from that call-back otherwise it will be called repeatedly.

Related

How to get info about completion of one of my animations in Unity?

I have monster named Fungant in my 2D platform game.
It can hide as mushroom and rise to his normal form.
I try to handle it in code, but I don't know how to get information about finished animation (without it, animation of rising and hiding always was skipped).
I think the point there is to get info about complete of the one of two animations - Rise and Hide.
There is current code:
if (
fungantAnimator.GetCurrentAnimatorStateInfo(0).IsName("Fungant Rise")
)
{
fungantAnimator.SetBool("isRising", false);
isRisen = true;
fungantRigidbody.velocity = new Vector2(
walkSpeed * Mathf.Sign(
player.transform.position.x - transform.position.x),
fungantRigidbody.velocity.y
);
}
if (fungantAnimator.GetCurrentAnimatorStateInfo(0).IsName("Fungant Hide"))
{
fungantAnimator.SetBool("isHiding", false);
isRisen = false;
}
I try this two ways:
StateMachineBehaviour
I would like to get StateMachineBehaviour, but how to get it?
No idea how to process this further.
AnimationEvents
Tried to do with animation event but every tutorial have list of functions to choose (looks easy), but in my Unity I can write Function, Float, Int, String or select object (what I should do?).
I decided to write test() function with Debug only inside, and create AnimationEvents with written "test()" in function field, but nothing happens.
Same as above, no more ideas how to process this further.
I personally would use animation events for this. Just add an event to the animation and then the event plays a function after the animation transition is finished.
For more information on how to use animation events you can click here.
This post may also help you to add an event when the animation is finished.
I hope this answer helps you to solve this problem.

Is there an function for "wait frame to end" like "WaitForEndOfFrame" in unity?

I need to do some calculations between every update(), so I need to ensure that a function is processed before the next frame.
Is there any way to achieve this? Just like "WaitForEndOfFrame" in Unity?
You can override the updateTree in your FlameGame (or in your Component, if you only want it to happen before the updates of a subtree) and do your calculations right before all the other components start updating. This would be right after the last frame, except for the first frame, but that one you can skip by setting a boolean.
So something like this:
class MyGame extends FlameGame {
bool isFirstTick = true;
#override
void updateTree(double dt) {
if(!isFirstTick) {
// Do your calculations
} else {
isFirstTick = false;
}
super.updateTree(dt);
}
}
But I have to ask, why do you need to do this? render won't be called until all the update calls are done, do can't you just put your calculations in the normal update method?
In Flutter we don't get an update() function unlike Unity. That is in the default API that we use, there are ways to tap into something of that effect. Normally we use a Ticker and create an animation to get periodic updates synced with screen refresh rate.
However, if what you are trying to do is to run something in between build() calls, WidgetsBinding.instance!.addPostFrameCallback() may be what you are looking for.
Here is a detailed answer that may help in this regard: https://stackoverflow.com/a/51273797/679553

Gstreamer 1.0 Pause signal

I need to detect when the current playing audio/video is paused. I cannot find anything for 1.0. My app is a bit complex but here is condensed code
/* This function is called when the pipeline changes states. We use it to
* keep track of the current state. */
static void state_changed_cb(GstBus *bus, GstMessage *msg, CustomData *data)
{
GstState old_state, new_state, pending_state;
gst_message_parse_state_changed(msg, &old_state, &new_state, &pending_state);
if(GST_MESSAGE_SRC(msg) == GST_OBJECT(data->playbin))
{
g_print("State set to %s\n", gst_element_state_get_name(new_state));
}
}
gst_init(&wxTheApp->argc, &argv);
m_playbin = gst_element_factory_make("playbin", "playbin");
if(!m_playbin)
{
g_printerr("Not all elements could be created.\n");
exit(1);
}
CustomData* data = new CustomData(xid, m_playbin);
GstBus *bus = gst_element_get_bus(m_playbin);
gst_bus_set_sync_handler(bus, (GstBusSyncHandler) create_window, data, NULL);//here I do video overly stuffs
g_signal_connect (G_OBJECT (bus), "message::state-changed", (GCallback)state_changed_cb, &data);
What do I do wrong? I cannot find working example on connecting such events on Gstreamer 1.0 and 0.x seems a bit different than 1.0 so the vast exaples there don't help
UPDATE
I have found a way to get signals. I run wxWidgets timer with 500ms time span and each time timer fires I call
GstMessage* msg = gst_bus_pop(m_bus);
if(msg!=NULL)
{
g_print ("New Message -- %s\n", gst_message_type_get_name(msg->type));
}
Now I get a lot of 'state-change' messages. Still I want to know if that message is for Pause or Stop or Play or End of Media (I mean way to differentiate which message is this) so that I can notify the UI.
So while I get signals now, the basic problem, to get specific signals, remains unsolved.
You have to call gst_bus_add_signal_watch() (like in 0.10) to enable emission of the signals. Without that you can only use the other ways to get notified about GstMessages on that bus.
Also just to be sure, you need a running GLib main loop on the default main context for this to work. Otherwise you need to do things a bit different.
For the updated question:
Check the documentation: gst_message_parse_state_changed() can be used to parse the old, new and pending state from the message. This is also still the same as in 0.10. From the application point of view, and conceptionally nothing much has changed really between 0.10 and 1.0
Also you shouldn't do this timeout-waiting as it will block your wxwidget main loop. Easiest solution would be to use a sync bus handler (which you already have) and dispatch all messages from there to some callback on the wxwidget main loop.

QApplication::processEvents never returns

In my application I need to wait until external program (using QProcess) is finished. I want to keep the application responsible so blocking methods are unacceptable.
Also I need to disallow user input. I've tried to make QEventLoop and exec it with QEventLoop::ExcludeUserInputEvents flag, but as documentation says it only delays an event handling:
the events are not discarded; they will be delivered the next time processEvents() is called without the ExcludeUserInputEvents flag.
So I implemented simple event filter and install it on qApp (the idea is took from Qt Application: Simulating modal behaviour (enable/disable user input)). It works well, but sometimes QApplication::processEvents function never returns even if I specify the maximum timeout. Could anyone help me to understand for what reasons it periodically happens?
class UserInputEater : public QObject
{
public:
bool eventFilter(QObject *object, QEvent *event)
{
switch(event->type())
{
case QEvent::UpdateRequest:
case QEvent::UpdateLater:
case QEvent::Paint:
return QObject::eventFilter(object, event);
default:
return true;
}
}
};
-
UserInputEater eventEater;
qApp->installEventFilter(&eventEater);
QProcess prc;
prc.start("...");
while(!prc.waitForFinished(10))
{
if(qApp->hasPendingEvents())
{
// Sometimes it never returns from processEvents
qApp->processEvents(QEventLoop::AllEvents, 100);
}
}
qApp->removeEventFilter(&eventEater);
UPD: Seems like it depends of the timeout value for QProcess::waitForFinished.
I guess you are filtering some useful events (for example, QEvent::SockAct could be involved). Try to add some debug output and find out which event types you're actually filtering. Or it might be better to specify the black list of events you want to block instead of white list of events you want to allow. See this answer.
Also you shouldn't use return QObject::eventFilter(object, event);. You should use return false. All other event filters will be called automatically.
This solution however seems weird and unreasonable to me because you can just call setEnabled(false) for your top level widget to block user input, and then you can use QApplication::processEvents without any flags.

How to change controls simultaneously without repainting each one?

For example I need to disable two buttons in runtime. After I disabled first button it bacame gray, the second - it also became gray. But I do not know how to make the repainting simultaneous!
I need something like that:
freeze the Form (disable repainting)
disable first button
disable second button
Enable Form repainting
How to implement that?
Look at the Win32 API WM_SETREDRAW message. For example:
SendMessage(Handle, WM_SETREDRAW, False, 0);
Button1.Enabled := False;
Button2.Enabled := False;
SendMessage(Handle, WM_SETREDRAW, True, 0);
InvalidateRect(Handle, nil, True);
Messages cannot be processed until your application re-enters a message loop, so any attempt to modify/update control state that relies on message processing will not work within a single sequence of code that does not "pump" messages.
Fortunately the VCL controls typically provide a means for force repainting without waiting for messages to be processed, via the Update method:
Button1.Enabled := False;
Button2.Enabled := False;
Button1.Update;
Button2.Update;
This works independently of having to disable form repainting. The form will not repaint until your application goes into a message loop anyway, so disabling form painting and re-enabling within a single procedure that does not itself cause message processing is a waste of time.
This may not be exactly simultaneous repainting of the two buttons, but truly simultaneous painting of two separate control is impossible without getting into multithreaded GUI painting code which I think is way beyond the scope of this problem. Calling Update on two buttons in this way will be as near simultaneous in effect as you need however.
To Elias551:
LockWindowUpdate is probably not the best way to handle this since it is intended for drag and drop operations and can introduce subtle bugs when misused.
See http://blogs.msdn.com/b/oldnewthing/archive/2007/02/22/1742084.aspx
Instead use SendMessage(hwnd, WM_SETREDRAW, FALSE, 0)
The above decision with WM_SETREDRAW does not update child windows.
Instead, i recommend RedrawWindow:
RedrawWindow(Handle, nil, 0, RDW_INVALIDATE or RDW_ALLCHILDREN);
This could help: the API LockWindowUpdate(Handle: HWND) locks drawing to the handle and children.
ex:
procedure TForm1.ColorButtons();
begin
LockWindowUpdate(Self.Handle);
// Make some stuff
LockWindowUpdate(0);
end;
Once the locked handle is reset, the component is repainted