如何在QQuickPaintedItem中选择区域

Question

I want to build a selection tool for my qml image editor.

For this, I'm looking for an similar function like setSelectedArea in a QGraphicsScene . Has someone a solution for this?

Greetings

Edit: Maybe I can write a Plugin for my selection tool which extends the QQuickItem and draw a QPolygon with openGL.

Answer 1

You need to implement selection yourself.

You can create MouseArea that will track mouse activity and update selected rect accordingly. I mean something like this:

DocumentViewer { // Your QQuickPaintedItem
    id: viewer
    MouseArea {
        anchors.fill: parent
        acceptedButtons: Qt.LeftButton
        property real originX: 0
        property real originY: 0
        onPressed: {
            originX = mouse.x
            originY = mouse.y
        }
        onPositionChanged: {
            var width = mouse.x - originX
            var height = mouse.y - originY
            viewer.selectionRect = Qt.rect(originX, originY, width, height)
        }
    }
}

Then you'll be able to update and paint the selection rectangle in your viewer's selectionRect property setter.