Scene.DrawBackgrount: want to know dimensions of view window

[lightning2911]

I have a MyScene derived from QGraphicsScene where I implement a drawBackground. I now paint the sceneRect() with a grid. But I would like to extend painting the grid to the outside area if the sceneRect is smaller than the view window. How do I get these dimensions?

[tbscope]

But I would like to extend painting the grid to the outside area if the sceneRect is smaller than the view window.

I read that 10 times, but I still do not get it.
Can you explain this a little bit better?

What is an outside area?
What is a sceneRect?
What is a view window?

[aamer4yu]

Better use QGraphicsView::drawBackground instead of the scene background

[lightning2911]

I read that 10 times, but I still do not get it.
Can you explain this a little bit better?

I will try with an image or two:



This is a scene where the sceneRect() is painted gray and dots are painted on grid position. The sceneRect is centered in the window.

How do I know the dimensions of the white space around so that I can fill this space also with grid dots (or whatever)? I want to achieve this:


For this screen i have just added a fixed amount to the screenRect but I would like to know what the dimensions of that space around the sceneRect really are.

This is what the code looks like.

class MyScene(QGraphicsScene):
 
    def __init__(self, parent=None):
        super(MyScene, self).__init__(parent)
        self.pen = QPen(Qt.black, 1, Qt.SolidLine)
        self.brush = QBrush(Qt.gray, Qt.SolidPattern)
        self.gridSize = SCREEN_GRID_SIZE
        self.gridX = SCREEN_GRID_X
        self.gridY = SCREEN_GRID_Y
        self.setSceneRect(- self.gridSize * self.gridX / 2, - self.gridSize * self.gridY / 2, self.gridSize * self.gridX, self.gridSize * self.gridY)
 
    def drawBackground(self, painter, rect):
        # draw a rect in size of sceneRect
 
        # draw frame
        painter.setPen(QPen(Qt.red, 0, Qt.NoPen))
        painter.setBrush(QBrush(Qt.lightGray, Qt.SolidPattern))
        painter.drawRect(self.sceneRect())
 
        # draw grid
        painter.setBrush(QBrush(Qt.darkGray, Qt.SolidPattern))
        print self.sceneRect()
        for y in range(int(self.sceneRect().y()), int(self.sceneRect().y())+int(self.sceneRect().height()+1), self.gridSize):
            for x in range(int(self.sceneRect().x()), int(self.sceneRect().x())+int(self.sceneRect().width()+1), self.gridSize):
                # change color for center point
                if x == 0 and y == 0:
                    painter.save()
                    painter.setBrush(QBrush(Qt.red, Qt.SolidPattern))
                # draw a point
                painter.drawRect(x-1, y-1, 2, 2)
                # change color back if center point
                if x == 0 and y == 0:
                    painter.restore()

class MyScene(QGraphicsScene):
    
    def __init__(self, parent=None):
        super(MyScene, self).__init__(parent)
        self.pen = QPen(Qt.black, 1, Qt.SolidLine)
        self.brush = QBrush(Qt.gray, Qt.SolidPattern)
        self.gridSize = SCREEN_GRID_SIZE
        self.gridX = SCREEN_GRID_X
        self.gridY = SCREEN_GRID_Y
        self.setSceneRect(- self.gridSize * self.gridX / 2, - self.gridSize * self.gridY / 2, self.gridSize * self.gridX, self.gridSize * self.gridY)
        
    def drawBackground(self, painter, rect):
        # draw a rect in size of sceneRect
        
        # draw frame
        painter.setPen(QPen(Qt.red, 0, Qt.NoPen))
        painter.setBrush(QBrush(Qt.lightGray, Qt.SolidPattern))
        painter.drawRect(self.sceneRect())
        
        # draw grid
        painter.setBrush(QBrush(Qt.darkGray, Qt.SolidPattern))
        print self.sceneRect()
        for y in range(int(self.sceneRect().y()), int(self.sceneRect().y())+int(self.sceneRect().height()+1), self.gridSize):
            for x in range(int(self.sceneRect().x()), int(self.sceneRect().x())+int(self.sceneRect().width()+1), self.gridSize):
                # change color for center point
                if x == 0 and y == 0:
                    painter.save()
                    painter.setBrush(QBrush(Qt.red, Qt.SolidPattern))
                # draw a point
                painter.drawRect(x-1, y-1, 2, 2)
                # change color back if center point
                if x == 0 and y == 0:
                    painter.restore()

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[lightning2911]

thanks aamer4yu, i did not see that the view also had a drawbackground method. got it working now.