Pyqt5 QgraphicsView如何在滚动条限制外进行平移

Question

我有一组预定的X和Y坐标，用于将QGraphicsItem作为点放置，然后将每个点放置在QGraphicsView中。我将我的平移按钮设置为中间鼠标按钮，但只有在缩放后才能平移。此外，我只能平移到最远的点。

是否有一种方法可以设置QGraphicsView，使其不会停止在某一点处，而是可以在任何缩放级别下平移？此外，作为一个附注，以后我想能够选择这些点以从它们那里设置和获取属性，因此我仍然希望能够与它们进行交互？

更新

我制作了几个gif来展示当前控件如何工作，以及我希望它们如何工作。

目前

您可以在这里看到，我无法超出滚动条的限制 我想要的

我希望能够移动屏幕，超出方块放置的范围，这样用户可以将一些内容移出屏幕或者缩小到比 fitInView 允许的范围更小。我知道缩放部分在我的滚轮事件中，只是还没有改变它。最重要的是，能够在任何缩放级别下将它们移动到超出范围之外。

请告诉我是否需要更多解释。

代码

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys
from math import sqrt

class Point(QGraphicsItem):
    def __init__(self, x, y):
        super(Point, self).__init__()
        self.setFlag(QGraphicsItem.ItemIsSelectable, True)
        self.rectF = QRectF(0, 0, 30, 30)
        self.x=x
        self.y=y
        self._brush = QBrush(Qt.black)

    def setBrush(self, brush):
        self._brush = brush
        self.update()

    def boundingRect(self):
        return self.rectF

    def paint(self, painter=None, style=None, widget=None):
        painter.fillRect(self.rectF, self._brush)

    def hoverMoveEvent(self, event):
        point = event.pos().toPoint()
        print(point)
        QGraphicsItem.hoverMoveEvent(self, event)


class Viewer(QGraphicsView):
    photoClicked = pyqtSignal(QPoint)
    rectChanged = pyqtSignal(QRect)

    def __init__(self, parent):
        super(Viewer, self).__init__(parent)
        self.rubberBand = QRubberBand(QRubberBand.Rectangle, self)
        self.setMouseTracking(True)
        self.origin = QPoint()
        self.changeRubberBand = False

        self._zoom = 0
        self._empty = True
        self._scene = QGraphicsScene(self)

        self.setTransformationAnchor(QGraphicsView.AnchorUnderMouse)
        self.setResizeAnchor(QGraphicsView.AnchorUnderMouse)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setFrameShape(QFrame.NoFrame)
        self.area = float()
        self.setPoints()
        QTimer.singleShot(0, self.fitInView) # This is done so that it can fit into view on load

    def setItems(self):
            self.data = {'x': [-2414943.8686, -2417160.6592, -2417160.6592, -2417856.1783, -2417054.7618, -2416009.9966, -2416012.5232, -2418160.8952, -2418160.8952, -2416012.5232, -2417094.7694, -2417094.7694], 'y': [10454269.7008,
     10454147.2672, 10454147.2672, 10453285.2456, 10452556.8132, 10453240.2808, 10455255.8752, 10455183.1912, 10455183.1912, 10455255.8752, 10456212.5959, 10456212.5959]}
            maxX = max(self.data['x'])
            minX = min(self.data['x'])
            maxY = max(self.data['y'])
            minY = min(self.data['y'])
            distance = sqrt((maxX-minX)**2+(maxY-minY)**2)

            self.area = QRectF(minX, minY, distance, distance)
            for i,x in enumerate(self.data['x']):
                x = self.data['x'][i]
                y = self.data['y'][i]
                p = Point(x,y)
                p.setPos(x,y)
                self._scene.addItem(p)
            self.setScene(self._scene)



    def fitInView(self, scale=True):
        rect = QRectF(self.area)
        if not rect.isNull():
            self.setSceneRect(rect)

            unity = self.transform().mapRect(QRectF(0, 0, 1, 1))
            self.scale(1 / unity.width(), 1 / unity.height())
            viewrect = self.viewport().rect()
            scenerect = self.transform().mapRect(rect)
            factor = min(viewrect.width() / scenerect.width(),
                             viewrect.height() / scenerect.height())
            self.scale(factor, factor)
            self._zoom = 0


    def setPoints(self):
        self._zoom = 0
        self.setItems()
        self.setDragMode(self.ScrollHandDrag)
        # self.fitInView()

    def wheelEvent(self, event):
            if event.angleDelta().y() > 0:
                factor = 1.25
                self._zoom += 1
            else:
                factor = 0.8
                self._zoom -= 1
            if self._zoom > 0:
                self.scale(factor, factor)
            elif self._zoom == 0:
                self.fitInView()
            else:
                self._zoom = 0


    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:

            self.origin = event.pos()
            self.rubberBand.setGeometry(QRect(self.origin, QSize()))
            self.rectChanged.emit(self.rubberBand.geometry())
            self.rubberBand.show()
            self.changeRubberBand = True
            return
            #QGraphicsView.mousePressEvent(self,event)
        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.ClosedHandCursor)
            self.original_event = event
            handmade_event = QMouseEvent(QEvent.MouseButtonPress,QPointF(event.pos()),Qt.LeftButton,event.buttons(),Qt.KeyboardModifiers())
            QGraphicsView.mousePressEvent(self,handmade_event)

        super(Viewer, self).mousePressEvent(event)

    def mouseReleaseEvent(self, event):
        if event.button() == Qt.LeftButton:
            self.changeRubberBand = False
            QGraphicsView.mouseReleaseEvent(self,event)
        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.OpenHandCursor)
            handmade_event = QMouseEvent(QEvent.MouseButtonRelease,QPointF(event.pos()),Qt.LeftButton,event.buttons(),Qt.KeyboardModifiers())
            QGraphicsView.mouseReleaseEvent(self,handmade_event)
        super(Viewer, self).mouseReleaseEvent(event)


    def mouseMoveEvent(self, event):
        if self.changeRubberBand:
            self.rubberBand.setGeometry(QRect(self.origin, event.pos()).normalized())
            self.rectChanged.emit(self.rubberBand.geometry())
            QGraphicsView.mouseMoveEvent(self,event)
        super(Viewer, self).mouseMoveEvent(event)

class Window(QWidget):
    def __init__(self):
        super(Window, self).__init__()
        self.viewer = Viewer(self)
        self.btnLoad = QToolButton(self)
        self.btnLoad.setText('Fit Into View')
        self.btnLoad.clicked.connect(self.fitPoints)

        VBlayout = QVBoxLayout(self)
        VBlayout.addWidget(self.viewer)
        HBlayout = QHBoxLayout()
        HBlayout.setAlignment(Qt.AlignLeft)
        HBlayout.addWidget(self.btnLoad)

        VBlayout.addLayout(HBlayout)
        self.viewer.fitInView()

    def fitPoints(self):
        self.viewer.fitInView()



if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    window.setGeometry(500, 300, 800, 600)
    window.show()
    sys.exit(app.exec_())

- laxer

---

我已经更新了，请试一试。 - Haru

Answer 1

更新2

请尝试以下代码。如果适合你，我想添加新的解释。

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys
from math import sqrt
class Line(QGraphicsLineItem):
    def __init__(self, x1, y1, x2, y2):
        super(Line, self).__init__()
        pen = self.pen()
        pen.setWidth(10)
        pen.setColor(Qt.gray)
        pen.setStyle(Qt.SolidLine)

        self.setPen(pen)
        self.origin = self.pos()
        self.setZValue(1)
        self.setLine(QLineF(x1, y1, x2, y2))
class Point(QGraphicsItem):
    def __init__(self, x, y):
        super(Point, self).__init__()
        self.setFlag(QGraphicsItem.ItemIsSelectable, True)
        self.rectF = QRectF(0, 0, 30, 30)
        self.x=x
        self.y=y
        self.origin = QPointF(self.pos())
        self._brush = QBrush(Qt.black)
        self.setZValue(2)
    def setBrush(self, brush):
        self._brush = brush
        self.update()

    def boundingRect(self):
        return self.rectF

    def paint(self, painter=None, style=None, widget=None):
        painter.fillRect(self.rectF, self._brush)

    def hoverMoveEvent(self, event):
        point = event.pos().toPoint()
        print(point)
        QGraphicsItem.hoverMoveEvent(self, event)


class Viewer(QGraphicsView):
    photoClicked = pyqtSignal(QPoint)
    rectChanged = pyqtSignal(QRect)

    def __init__(self, parent):
        super(Viewer, self).__init__(parent)
        self.rubberBand = QRubberBand(QRubberBand.Rectangle, self)
        self.setMouseTracking(True)
        self.origin = QPoint()
        self.changeRubberBand = False
        self.mid_panning = False     



        self._zoom = 0
        self._empty = True
        self._scene = QGraphicsScene(self)
        self._scene.setBackgroundBrush(Qt.white)
        self.white_board = QGraphicsRectItem()
        self.white_board.setZValue(1)
        self.white_board.setBrush(Qt.white)
        self.setTransformationAnchor(QGraphicsView.AnchorUnderMouse)
        self.setResizeAnchor(QGraphicsView.AnchorUnderMouse)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setFrameShape(QFrame.NoFrame)
        self.area = float()
        self.setPoints()
        self._old_x = QCursor.pos().x()
        self._old_y = QCursor.pos().y()

        QTimer.singleShot(0, self.fitInView) # This is done so that it can fit into view on load

    def setItems(self):
            self.data = {'x': [-2414943.8686, -2417160.6592, -2417160.6592, -2417856.1783, -2417054.7618, -2416009.9966, -2416012.5232, -2418160.8952, -2418160.8952, -2416012.5232, -2417094.7694, -2417094.7694], 'y': [10454269.7008,
     10454147.2672, 10454147.2672, 10453285.2456, 10452556.8132, 10453240.2808, 10455255.8752, 10455183.1912, 10455183.1912, 10455255.8752, 10456212.5959, 10456212.5959]}
            maxX = max(self.data['x'])
            minX = min(self.data['x'])
            maxY = max(self.data['y'])
            minY = min(self.data['y'])
            distance = sqrt((maxX-minX)**2+(maxY-minY)**2)

            self.area = QRectF(minX , minY , distance , distance )
            self.white_board.setRect(QRectF(minX , minY , distance , distance ))
            self._scene.addItem(self.white_board)
            line1 = Line(minX, minY, minX+distance, minY+distance)
            line2 = Line(minX+distance, minY, minX, minY+distance)
            self._scene.addItem(line1)
            self._scene.addItem(line2)
            for i,x in enumerate(self.data['x']):
                x = self.data['x'][i]
                y = self.data['y'][i]
                p = Point(x,y)
                p.setPos(x,y)
                self._scene.addItem(p)

            self.setScene(self._scene)


    def make_area2(self, area):
        x = area.x()
        y = area.y()
        width = area.width()
        height = area.height()
        x -= 2*x
        y -= 2*y
        width = width*2
        height = height*2
        area = QRectF(x, y, width, height)
        return area
    def fitInView(self, scale=True):
        rect = QRectF(self.area)
        if not rect.isNull():
            self.setSceneRect(rect)
            unity = self.transform().mapRect(QRectF(0, 0, 1, 1))
            print(unity.width(), unity.height())
            self.scale(1 / unity.width(), 1 / unity.height())
            viewrect = self.viewport().rect()
            scenerect = self.transform().mapRect(rect)
            factor = min(viewrect.width() / scenerect.width(),
                             viewrect.height() / scenerect.height())
            print(scenerect.width(), scenerect.height())
            self.scale(factor, factor)

            self._zoom = 0



    def setPoints(self):
        self._zoom = 0
        self.setItems()
        self.setDragMode(self.ScrollHandDrag)
        # self.fitInView()

    def wheelEvent(self, event):
            if event.angleDelta().y() > 0:
                factor = 1.25
                self._zoom += 1
            else:
                factor = 0.8
                self._zoom -= 1
            if self._zoom > 0:
                self.scale(factor, factor)
            elif self._zoom == 0:
                self.fitInView()
            else:
                self._zoom = 0


    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:

            self.origin = event.pos()
            self.rubberBand.setGeometry(QRect(self.origin, QSize()))
            self.rectChanged.emit(self.rubberBand.geometry())
            self.rubberBand.show()
            self.changeRubberBand = True
            return
            #QGraphicsView.mousePressEvent(self,event)
        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.ClosedHandCursor)
            self.origin = event.pos()
            self.original_event = event
            self.mid_panning = True
            self.scene_origin = self.mapToScene(event.pos())
            self._old_x = QCursor.pos().x()
            self._old_y = QCursor.pos().y()
            for i in self._scene.items():

                i.origin = i.pos()
            # I recommend that you get the all item position.
            handmade_event = QMouseEvent(QEvent.MouseButtonPress,QPointF(event.pos()),Qt.LeftButton,event.buttons(),Qt.KeyboardModifiers())
            QGraphicsView.mousePressEvent(self,handmade_event)

        super(Viewer, self).mousePressEvent(event)

    def mouseReleaseEvent(self, event):
        if event.button() == Qt.LeftButton:
            self.changeRubberBand = False
            QGraphicsView.mouseReleaseEvent(self,event)
        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.OpenHandCursor)
            handmade_event = QMouseEvent(QEvent.MouseButtonRelease,QPointF(event.pos()),Qt.LeftButton,event.buttons(),Qt.KeyboardModifiers())
            self.mid_panning = False
            # here you set the original point.
            for i in self._scene.items():
                i.setPos(i.origin)
            QGraphicsView.mouseReleaseEvent(self,handmade_event)
        super(Viewer, self).mouseReleaseEvent(event)
    def calc_offset(self, x, y):
        offset_x = x - int(self.viewport().width()/2)
        offset_y = y - int(self.viewport().height()/2)
        return offset_x, offset_y

    def mouseMoveEvent(self, event):        
        if self.changeRubberBand:
            self.rubberBand.setGeometry(QRect(self.origin, event.pos()).normalized())
            self.rectChanged.emit(self.rubberBand.geometry())
            QGraphicsView.mouseMoveEvent(self,event)
        elif self.mid_panning:         

            new_x = event.x()
            new_y = event.y()
            offset_x, offset_y = self.calc_offset(new_x, new_y)
            for item in self._scene.items():
                item.setPos(QPointF(item.pos().x() - (new_x - self._old_x)*10, item.pos().y() - (new_y - self._old_y)*10))     


            self._old_x = new_x
            self._old_y = new_y
            return

        super(Viewer, self).mouseMoveEvent(event)

class Window(QWidget):
    def __init__(self):
        super(Window, self).__init__()
        self.viewer = Viewer(self)
        self.btnLoad = QToolButton(self)
        self.btnLoad.setText('Fit Into View')
        self.btnLoad.clicked.connect(self.fitPoints)

        VBlayout = QVBoxLayout(self)
        VBlayout.addWidget(self.viewer)
        HBlayout = QHBoxLayout()
        HBlayout.setAlignment(Qt.AlignLeft)
        HBlayout.addWidget(self.btnLoad)

        VBlayout.addLayout(HBlayout)
        self.viewer.fitInView()

    def fitPoints(self):
        self.viewer.fitInView()



if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    window.setGeometry(300, 400, 800, 600)
    window.show()
    sys.exit(app.exec_())

更新

关键解决方案是使用scroll(dx, dy)。

解释

一开始，我怀疑是否有“屏幕外”的地方。原因是QGraphicsView仅显示场景中的QGraphicsScene和QGraphicsItem。QGraphicsView可以显示整个场景或部分场景，但我认为它无法显示“屏幕外”。

我有过使用pygame的经验，所以尝试实现“偏移量”的想法，但是pygame本身具有无限广阔的屏幕，只显示其一小部分。因此，我们可以看到“屏幕外”。相反，QGraphicsScene是一个有限的屏幕，用户通过setSceneRect来确定范围。fitInView表示相同范围的屏幕。

但是QGraphicsView是用于显示场景的小部件。我们可以滚动小部件。因此，我们可以通过滚动小部件本身来达到同样的效果。

代码。

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys
from math import sqrt

class Point(QGraphicsItem):
    def __init__(self, x, y):
        super(Point, self).__init__()
        self.setFlag(QGraphicsItem.ItemIsSelectable, True)
        self.rectF = QRectF(0, 0, 30, 30)
        self.x=x
        self.y=y
        self._brush = QBrush(Qt.black)

    def setBrush(self, brush):
        self._brush = brush
        self.update()

    def boundingRect(self):
        return self.rectF

    def paint(self, painter=None, style=None, widget=None):
        painter.fillRect(self.rectF, self._brush)

    def hoverMoveEvent(self, event):
        point = event.pos().toPoint()
        print(point)
        QGraphicsItem.hoverMoveEvent(self, event)


class Viewer(QGraphicsView):
    photoClicked = pyqtSignal(QPoint)
    rectChanged = pyqtSignal(QRect)

    def __init__(self, parent):
        super(Viewer, self).__init__(parent)
        self.rubberBand = QRubberBand(QRubberBand.Rectangle, self)
        self.setMouseTracking(True)
        self.origin = QPoint()
        self.changeRubberBand = False
        self.mid_panning = False     



        self._zoom = 0
        self._empty = True
        self._scene = QGraphicsScene(self)

        self.setTransformationAnchor(QGraphicsView.AnchorUnderMouse)
        self.setResizeAnchor(QGraphicsView.AnchorUnderMouse)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setFrameShape(QFrame.NoFrame)
        self.area = float()
        self.setPoints()
        QTimer.singleShot(0, self.fitInView) # This is done so that it can fit into view on load

    def setItems(self):
            self.data = {'x': [-2414943.8686, -2417160.6592, -2417160.6592, -2417856.1783, -2417054.7618, -2416009.9966, -2416012.5232, -2418160.8952, -2418160.8952, -2416012.5232, -2417094.7694, -2417094.7694], 'y': [10454269.7008,
     10454147.2672, 10454147.2672, 10453285.2456, 10452556.8132, 10453240.2808, 10455255.8752, 10455183.1912, 10455183.1912, 10455255.8752, 10456212.5959, 10456212.5959]}
            maxX = max(self.data['x'])
            minX = min(self.data['x'])
            maxY = max(self.data['y'])
            minY = min(self.data['y'])
            distance = sqrt((maxX-minX)**2+(maxY-minY)**2)

            self.area = QRectF(minX, minY, distance, distance)
            for i,x in enumerate(self.data['x']):
                x = self.data['x'][i]
                y = self.data['y'][i]
                p = Point(x,y)
                p.setPos(x,y)
                self._scene.addItem(p)
            self.setScene(self._scene)



    def fitInView(self, scale=True):
        rect = QRectF(self.area)
        if not rect.isNull():
            self.setSceneRect(rect)
            unity = self.transform().mapRect(QRectF(0, 0, 1, 1))
            print(unity.width(), unity.height())
            self.scale(1 / unity.width(), 1 / unity.height())
            viewrect = self.viewport().rect()
            scenerect = self.transform().mapRect(rect)
            factor = min(viewrect.width() / scenerect.width(),
                             viewrect.height() / scenerect.height())
            self.scale(factor, factor)
            self._zoom = 0


    def setPoints(self):
        self._zoom = 0
        self.setItems()
        self.setDragMode(self.ScrollHandDrag)
        # self.fitInView()

    def wheelEvent(self, event):
            if event.angleDelta().y() > 0:
                factor = 1.25
                self._zoom += 1
            else:
                factor = 0.8
                self._zoom -= 1
            if self._zoom > 0:
                self.scale(factor, factor)
            elif self._zoom == 0:
                self.fitInView()
            else:
                self._zoom = 0


    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:

            self.origin = event.pos()
            self.rubberBand.setGeometry(QRect(self.origin, QSize()))
            self.rectChanged.emit(self.rubberBand.geometry())
            self.rubberBand.show()
            self.changeRubberBand = True
            return
            #QGraphicsView.mousePressEvent(self,event)
        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.ClosedHandCursor)
            self.origin = event.pos()
            self.original_event = event
            self.mid_panning = True
            self.scene_origin = self.mapToScene(event.pos())
            handmade_event = QMouseEvent(QEvent.MouseButtonPress,QPointF(event.pos()),Qt.LeftButton,event.buttons(),Qt.KeyboardModifiers())
            QGraphicsView.mousePressEvent(self,handmade_event)

        super(Viewer, self).mousePressEvent(event)

    def mouseReleaseEvent(self, event):
        if event.button() == Qt.LeftButton:
            self.changeRubberBand = False
            QGraphicsView.mouseReleaseEvent(self,event)
        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.OpenHandCursor)
            handmade_event = QMouseEvent(QEvent.MouseButtonRelease,QPointF(event.pos()),Qt.LeftButton,event.buttons(),Qt.KeyboardModifiers())
            self.mid_panning = False
            QGraphicsView.mouseReleaseEvent(self,handmade_event)
        super(Viewer, self).mouseReleaseEvent(event)
    def calc_offset(self, x, y):
        offset_x = x - int(self.viewport().width()/2)
        offset_y = y - int(self.viewport().height()/2)
        return offset_x, offset_y
    def mouseMoveEvent(self, event):        
        if self.changeRubberBand:
            self.rubberBand.setGeometry(QRect(self.origin, event.pos()).normalized())
            self.rectChanged.emit(self.rubberBand.geometry())
            QGraphicsView.mouseMoveEvent(self,event)
        elif self.mid_panning:         
            offset_x, offset_y = self.calc_offset(event.pos().x(), event.pos().y())
            self.scroll(offset_x,offset_y)
            return

        super(Viewer, self).mouseMoveEvent(event)

class Window(QWidget):
    def __init__(self):
        super(Window, self).__init__()
        self.viewer = Viewer(self)
        self.btnLoad = QToolButton(self)
        self.btnLoad.setText('Fit Into View')
        self.btnLoad.clicked.connect(self.fitPoints)

        VBlayout = QVBoxLayout(self)
        VBlayout.addWidget(self.viewer)
        HBlayout = QHBoxLayout()
        HBlayout.setAlignment(Qt.AlignLeft)
        HBlayout.addWidget(self.btnLoad)

        VBlayout.addLayout(HBlayout)
        self.viewer.fitInView()

    def fitPoints(self):
        self.viewer.fitInView()



if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    window.setGeometry(300, 400, 800, 600)
    window.show()
    sys.exit(app.exec_())

- Haru

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我已经更新了原始帖子，希望能更清楚地表达我想要实现的目标。谢谢你的帮助。 - laxer

@laxer 我明白了，谢谢你的更新。 - Haru

太好了！我需要稍微调整一下缩放，因为我的滚轮事件，这会让我走上正确的轨道。谢谢你的帮助！ - laxer

大家好，我有一个相似的问题，但是我不想移动QGraphicsView本身，我想在QGraphicsScene内部导航。基本上能够在场景内部无限制地平移。你知道怎么做吗？ - Vlad

我明白了，非常感谢。最近我在关于PyQt方面制作了太多的副本，在看到你的答案后，它似乎是解决我的问题的完美方案 :) - Vlad