python - 更改 QGraphicsView 的方向

Question

我有一些 x 和 y 坐标，它们与一些 QGraphicItems 关联，然后放入 QGraphicView 中。我最近注意到，在使用橡皮筋功能选择项目时，我的点方向不正确。

我有 4 个重叠的点，它们重叠在错误的位置，我做了一些调试，发现我的原点从左上角开始，Y+ 向下，X+ 向右。

我希望我的系统 Y+ 会随着它的上升而变大。我截取了屏幕截图来显示代码当前的结果(我将粘贴在下面)，并将数字放在点旁边。这些数字代表该位置有多少个点。另外，我还设置了 X 和 Y 方向。

然后移动点旁边的数字来代表我想要实现的目标。以及我正在寻找的 X 和 Y 方向。

我还注意到它似乎正在标准化坐标。如果我能保留实际的 X 和 Y 位置那就最好了。

这是我目前拥有的照片

这就是我想要的

这是我当前的代码

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

class LogObject(QObject):
    hovered = pyqtSignal()
    notHovered = pyqtSignal()

class Point(QGraphicsRectItem):
    def __init__(self, x, y, name):
        super(Point, self).__init__(QRectF(0, 0, 30, 30))
        self.setFlag(QGraphicsItem.ItemIsSelectable, True)
        self.name = name
        self.x = x
        self.y = y
        self.setBrush(QBrush(Qt.black))
        self.setAcceptHoverEvents(True)
        self.log = LogObject()
        self.setPos(x, y)

    def itemChange(self, change, value):
        if change == self.ItemSelectedChange:
            self.setBrush(QBrush(Qt.green) if value else QBrush(Qt.black))
        return QGraphicsItem.itemChange(self, change, value)

    def hoverEnterEvent(self, event):
        self.setBrush(QColor("red"))
        self.log.hovered.emit()
        QGraphicsItem.hoverMoveEvent(self, event)

    def hoverLeaveEvent(self, event):
        self.setBrush(QColor("black"))
        self.log.notHovered.emit()
        QGraphicsItem.hoverMoveEvent(self, event)

    def mousePressEvent(self, event):
        print(self.name)
        QGraphicsItem.mousePressEvent(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
        self.viewport().setCursor(Qt.ArrowCursor)

    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._scene.setSceneRect(QRectF(minX, -minY, distance, distance)) # Tried this but didn't seem to do anything
            for i, (x, y) in enumerate(zip(self.data["x"], self.data["y"])):
                p = Point(x, y, "Point__" + str(i))
                p.log.hovered.connect(self.hoverChange)
                p.log.notHovered.connect(self.notHoverChange)
                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)

    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 hoverChange(self):
        self.viewport().setCursor(Qt.PointingHandCursor)

    def notHoverChange(self):
        self.viewport().setCursor(Qt.ArrowCursor)

    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

        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):
        point= event.pos()
        print(point)
        if event.button() == Qt.LeftButton:
            self.changeRubberBand = False
            if self.rubberBand.isVisible():
                self.rubberBand.hide()
                rect = self.rubberBand.geometry()
                rect_scene = self.mapToScene(rect).boundingRect()
                selected = self.scene().items(rect_scene)
            if selected:
                print(
                    "".join("Item: %s\n" % child.name for child in selected)
                )
            else:
                print(" Nothing\n")
            QGraphicsView.mouseReleaseEvent(self, event)

        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.ArrowCursor)
            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)

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

Answer 1

这个想法是用 (1, -1) 缩放场景，这将使 Y 轴反转。另一方面，QGraphicsView 已经有一个 fitInView 方法，所以我将使用它，因为您当前的方法可能会产生问题

class LogObject(QObject):
    hovered = pyqtSignal()
    notHovered = pyqtSignal()


class Point(QGraphicsRectItem):
    def __init__(self, x, y, name):
        super(Point, self).__init__(QRectF(0, 0, 30, 30))
        self.setFlag(QGraphicsItem.ItemIsSelectable, True)
        self.name = name
        self.setBrush(QBrush(Qt.black))
        self.setAcceptHoverEvents(True)
        self.log = LogObject()
        self.setPos(x, y)

    def itemChange(self, change, value):
        if change == self.ItemSelectedChange:
            self.setBrush(QBrush(Qt.green) if value else QBrush(Qt.black))
        return QGraphicsItem.itemChange(self, change, value)

    def hoverEnterEvent(self, event):
        self.setBrush(QColor("red"))
        self.log.hovered.emit()
        QGraphicsItem.hoverMoveEvent(self, event)

    def hoverLeaveEvent(self, event):
        self.setBrush(QColor("black"))
        self.log.notHovered.emit()
        QGraphicsItem.hoverMoveEvent(self, event)

    def mousePressEvent(self, event):
        print(self.name)
        QGraphicsItem.mousePressEvent(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.setScene(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()
        self.viewport().setCursor(Qt.ArrowCursor)
        QTimer.singleShot(0, self.reset_fit)

    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.scene().setSceneRect(
            QRectF(minX, -minY, distance, distance)
        )  # Tried this but didn't seem to do anything
        for i, (x, y) in enumerate(zip(self.data["x"], self.data["y"])):
            p = Point(x, y, "Point__" + str(i))
            p.log.hovered.connect(self.hoverChange)
            p.log.notHovered.connect(self.notHoverChange)
            self.scene().addItem(p)

    def setPoints(self):
        self.setItems()
        self.setDragMode(self.ScrollHandDrag)

    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.reset_fit()
        else:
            self._zoom = 0

    def hoverChange(self):
        self.viewport().setCursor(Qt.PointingHandCursor)

    def notHoverChange(self):
        self.viewport().setCursor(Qt.ArrowCursor)

    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

        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):
        point = event.pos()
        print(self.mapToScene(point))
        if event.button() == Qt.LeftButton:
            self.changeRubberBand = False
            if self.rubberBand.isVisible():
                self.rubberBand.hide()
                rect = self.rubberBand.geometry()
                rect_scene = self.mapToScene(rect).boundingRect()
                selected = self.scene().items(rect_scene)
                if selected:
                    print(
                        "".join("Item: %s\n" % child.name for child in selected)
                    )
                else:
                    print(" Nothing\n")
            QGraphicsView.mouseReleaseEvent(self, event)

        elif event.button() == Qt.MidButton:
            self.viewport().setCursor(Qt.ArrowCursor)
            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)

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

    def reset_fit(self):
        r = self.scene().itemsBoundingRect()
        self.resetTransform()
        self.setSceneRect(r)
        self.fitInView(r, Qt.KeepAspectRatio)
        self._zoom = 0
        self.scale(1, -1)


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)

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