Question

我在PySide2中有一个简单的代码，可以在屏幕上绘制多个QRect（20个红色QRect）。运行代码只会绘制这些QRect的单个（最后一个）实例。我在做什么错了？

def paintEvent(self, event:QPaintEvent):

    if self.cell != None:
        painter = QPainter(self)
        painter.setPen(Qt.NoPen)
        painter.setBrush(Qt.red)
        painter.drawRect(self.cell)

def drawBoard(self):

    cellWidth =  self.width / self.columns
    cellHeight = self.height / self.rows

    for r in range(0, self.rows):
        for c in range(0, self.columns):

            if (self.grid[r][c]):
                # this gets executed 20 times

                cellx = cellWidth * c
                celly = cellHeight * r
                self.cell = QRect(cellx, celly, cellWidth, cellHeight)

                # paint cell on widget
                self.update()

如何调用paintEvent在小部件上绘制多个实例？

Answer 1

除非另有说明，否则Qt通常会在调用QWidget方法之前擦除/填充paintEvent的背景-这就是为什么您只能看到最后一个矩形的原因。

尝试将绘制逻辑本身移至paintEvent中（未经测试）...

def paintEvent(self, event:QPaintEvent):
    if self.cell != None:
        painter = QPainter(self)
        painter.setPen(Qt.NoPen)
        painter.setBrush(Qt.red)
        cellWidth =  self.width / self.columns
        cellHeight = self.height / self.rows
        for r in range(0, self.rows):
            for c in range(0, self.columns):
                if (self.grid[r][c]):
                    # this gets executed 20 times

                    cellx = cellWidth * c
                    celly = cellHeight * r

                    # paint cell on widget
                    painter.drawRect(QRect(cellx, celly, cellWidth, cellHeight))

def drawBoard(self):
    self.update()

Qt无法在小部件上绘制多个QRect

1 个答案: