[Qt-interest] Animating from inital opacity of zero

[Jason H]

Yet another addendum....

It seems that a QGraphicsSvgItem works, but a QGraphicsRectItem doesn't. !?!? Which I hope is not the case because I put lots of things in rects to clip them. 




----- Original Message ----
From: Jason H <scorp1us at yahoo.com>
To: Jason H <scorp1us at yahoo.com>; qt-interest at trolltech.com
Sent: Mon, February 1, 2010 9:37:32 AM
Subject: Re: [Qt-interest] Animating from inital opacity of zero

To clarify:

Doesn't work:
item.setOpacity(0);
animation.setStartValue( 0)

Does work:
item.setOpacity(0.01);
animation.setStartValue( 0)




----- Original Message ----
From: Jason H <scorp1us at yahoo.com>
To: qt-interest at trolltech.com
Sent: Mon, February 1, 2010 1:02:13 AM
Subject: [Qt-interest] Animating from inital opacity of zero

I am having some trouble getting my QGraphicsItem animation fade-ins to work. It seems that if initial opacity is zero, the them item is optimized out? I have a simple wrapper that gives properties to QGraphicsItems (like QGraphicsWidget, but not) by proxying the properties to the item. (Like QGraphicsObject, but it provides a much thorougher mapping, and wraps an existing item, like a QGraphicsRectItem)

When I start with 0 opacity, it doesn't show. When I loop it, and switch between windows on my desktop, or resize the window, I then see it, so I think it is a optimization bug. I am wondering if there is some flag I have to set?

When I set the opacity to 0.01 it works fine, but there is a ghost image.

Ideas?


      

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