BUGFIX: GraphicsView::setScene(nullptr)

[cxxamz]

Type of change

• Bug fix

Description

GraphicsView::setScene support nullptr

Testing

• Qt version tested:
• Existing tests still pass

Breaking changes?

None.

Related issue

None.

---

Please fill out the sections above to help reviewers understand your changes.

[Llcoolsouder]

1. For clarity/brevity, I think it would be preferable to move your logic to the start of the function and then early return. This way we don't wrap everything in multiple if (scene) statements. e.g.

void GraphicsView::setScene(BasicGraphicsScene *scene)
{
    QGraphicsView::setScene(scene);
    if (!scene) {
        // Clear whatever is necessary
        return;
    }
    // Original function mostly untouched
    ...
}

2. What does this give us? Is this just more in line with the upstream QGraphicsScene::setScene() behaviour? Does calling this with nullptr clear the scene, do nothing, or something else?

[paceholder]

Is there any valid configuration when scene != nodeScene?
Shouldn't we better assert this condition?

[cxxamz]

Is this acceptable?

void GraphicsView::onDeleteSelectedObjects()
{
    if (!nodeScene()) return; 

    nodeScene()->undoStack().push(new DeleteCommand(nodeScene()));
}

[cxxamz]

1. For clarity/brevity, I think it would be preferable to move your logic to the start of the function and then early return. This way we don't wrap everything in multiple if (scene) statements. e.g.

void GraphicsView::setScene(BasicGraphicsScene *scene)
{
    QGraphicsView::setScene(scene);
    if (!scene) {
        // Clear whatever is necessary
        return;
    }
    // Original function mostly untouched
    ...
}

This approach is indeed better. I have fixed it in the next submission.

2. What does this give us? Is this just more in line with the upstream QGraphicsScene::setScene() behaviour? Does calling this with nullptr clear the scene, do nothing, or something else?

When click "Close", the program will crash because the scene is set to nullptr.

10-08-54.mp4

[lsouder-ozone3d]

Looks good to me now. 谢谢，太棒了！

Leaving this one for @paceholder to merge when he's ready.