CODEWITHSUNDEEP
qtqmlqt-quick
Paboka
Paboka

Reputation: 442

Prevent redrawing of underlayed elements int QtQuick Qml custom control

I have two custom QML components, inherited from QDeclarativeItem.

In constructors of my components I set this options:

setFlag(QGraphicsItem::ItemHasNoContents, false);
setCacheMode(QGraphicsItem::ItemCoordinateCache);

In my application I have an element of one type above an element of another type. This elements don't share any properties, but when one of them is redrawing, the another is redrawing too.

If I put some standard element above my elements (like a Text or Rectangle) and change it's properties, it doesn't make my elements redrawn. So I suppose, I've forgot to set some flag in my components.

How to prevent redrawing of one item when another is changing?

I'm using Qt 4.8 and QtQuick 1.1

Upvotes: 1

Views: 293

Answers (1)

Kuba hasn't forgotten Monica
Kuba hasn't forgotten Monica

Reputation: 98425

In any raster-based rendering system, the drawing is done on a backing store buffer. Thus, when anything changes in a QGraphicsView, all items that are not fully obscured must be drawn in back-to-front Z order. If any visible item changes, then all visible items that intersect it must be redrawn.

What you're seeing looks like normal behavior. Unless you provide some code, it's impossible to tell otherwise.

Upvotes: 1

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