Stack overflow when using MouseMoveEvent

Infestor

Hi,

So i tried to implement a scene with a moving view with the view moving when the mouse is near one of the borders of the screen (like in most RTS games). However i get a stack overflow when i do that.
My function looks like this

void Camera::mouseMoveEvent(QGraphicsSceneMouseEvent* e)
{
//view coordinates
int local_x = view->mapFromScene(e->pos()).x();
int local_y = view->mapFromScene(e->pos()).y();

int horizontalSliderPos = view->horizontalScrollBar()->sliderPosition();
int verticalSliderPos = view->verticalScrollBar()->sliderPosition();
if (local_x < 100) {
	view->horizontalScrollBar()->setSliderPosition(horizontalSliderPos -5);
}

This code is only for the one direction to make it easier. Could someone please enlighten me where or how an overflow is occuring here?

SGaist

Hi,

Aren't you triggering an infinite recursion ?

Infestor

I mean probably. Thats where the stack overflow should come from i guess. But my question was where this occurs oe rather how can i fix that?

Edit: From my (limited) understanding it should come from the fact that i trigger this event infinite times once the mouse is in the stated area. A fix for this would be to stop the event from happening once the slider is at its max/min position, but i have no idea how i would do that.

SGaist

Rather than relying on the slider position, shouldn't you rather define zones in which if the cursor can be found, the scrollbars are updated ?

Infestor

Isnt that what im doing? I only update the slider position if the cursor (local_x/y) is at a specific location (< 100 in this case for x).

SGaist

Something is not clear from your code, what class is Camera ?

Infestor

It inherits from QGraphicsRectItem and does not much else right now. It is added to the scene in the main class and then it grabs the mouse as otherwise the mouseMoveevent does not work.

Christian Ehrlicher

@infestor said in Stack overflow when using MouseMoveEvent:

Thats where the stack overflow should come from i guess

Simply looking at the backtrace will show it, it will also show you why it's a recursion.