Я искал этот пример, портированный на PyQt5 (python), но не нашел ни одного. Поэтому я написал это сам и хотел бы поделиться с вами (просто чтобы сэкономить ваше время). Он написан для Python 3.8, но должен работать и для более старых версий PyQt 5.14.1.
Существует небольшая разница с оригинальной реализацией C ++. QGraphicsScene должен быть явно установлен - в View классе конструктора и каждый новый объект Callout должен быть явно добавлен в сцену. Честно говоря, я не знаю почему, но мне все равно. Точно такая же версия библиотеки Qt в C ++ не требует этого.
import sys
from typing import List
from PyQt5.QtChart import QChart, QLineSeries, QSplineSeries
from PyQt5.QtCore import QPointF, QRect, QRectF, QSizeF, Qt
from PyQt5.QtGui import QColor, QFont, QFontMetrics, QMouseEvent, QPainter, QPainterPath, QResizeEvent
from PyQt5.QtWidgets import QApplication, QGraphicsItem, QGraphicsScene, QGraphicsSceneMouseEvent, \
QGraphicsSimpleTextItem, QGraphicsView, QStyleOptionGraphicsItem, QWidget
class Callout(QGraphicsItem):
def __init__(self, parent: QChart):
super().__init__()
self.m_chart: QChart = parent
self.m_text: str = ''
self.m_anchor: QPointF = QPointF()
self.m_font: QFont = QFont()
self.m_textRect: QRectF = QRectF()
self.m_rect: QRectF = QRectF()
def setText(self, text: str):
self.m_text = text
metrics = QFontMetrics(self.m_font)
self.m_textRect = QRectF(metrics.boundingRect(QRect(0, 0, 150, 150), Qt.AlignLeft, self.m_text))
self.m_textRect.translate(5, 5)
self.prepareGeometryChange()
self.m_rect = QRectF(self.m_textRect.adjusted(-5, -5, 5, 5))
self.updateGeometry()
def updateGeometry(self):
self.prepareGeometryChange()
self.setPos(self.m_chart.mapToPosition(self.m_anchor) + QPointF(10, -50))
def boundingRect(self) -> QRectF:
from_parent = self.mapFromParent(self.m_chart.mapToPosition(self.m_anchor))
anchor = QPointF(from_parent)
rect = QRectF()
rect.setLeft(min(self.m_rect.left(), anchor.x()))
rect.setRight(max(self.m_rect.right(), anchor.x()))
rect.setTop(min(self.m_rect.top(), anchor.y()))
rect.setBottom(max(self.m_rect.bottom(), anchor.y()))
return rect
def paint(self, painter: QPainter, option: QStyleOptionGraphicsItem, widget: QWidget):
path = QPainterPath()
mr = self.m_rect
path.addRoundedRect(mr, 5, 5)
anchor = QPointF(self.mapFromParent(self.m_chart.mapToPosition(self.m_anchor)))
if not mr.contains(anchor):
point1 = QPointF()
point2 = QPointF()
# establish the position of the anchor point in relation to self.m_rect
above = anchor.y() <= mr.top()
above_center = mr.top() < anchor.y() <= mr.center().y()
below_center = mr.center().y() < anchor.y() <= mr.bottom()
below = anchor.y() > mr.bottom()
on_left = anchor.x() <= mr.left()
left_of_center = mr.left() < anchor.x() <= mr.center().x()
right_of_center = mr.center().x() < anchor.x() <= mr.right()
on_right = anchor.x() > mr.right()
# get the nearest self.m_rect corner.
x = (on_right + right_of_center) * mr.width()
y = (below + below_center) * mr.height()
corner_case = (above and on_left) or (above and on_right) or (below and on_left) or (below and on_right)
vertical = abs(anchor.x() - x) > abs(anchor.y() - y)
horizontal = bool(not vertical)
x1 = x + left_of_center * 10 - right_of_center * 20 + corner_case * horizontal * (
on_left * 10 - on_right * 20)
y1 = y + above_center * 10 - below_center * 20 + corner_case * vertical * (above * 10 - below * 20)
point1.setX(x1)
point1.setY(y1)
x2 = x + left_of_center * 20 - right_of_center * 10 + corner_case * horizontal * (
on_left * 20 - on_right * 10)
y2 = y + above_center * 20 - below_center * 10 + corner_case * vertical * (above * 20 - below * 10)
point2.setX(x2)
point2.setY(y2)
path.moveTo(point1)
path.lineTo(anchor)
path.lineTo(point2)
path = path.simplified()
painter.setPen(QColor(30, 30, 30))
painter.setBrush(QColor(255, 255, 255))
painter.drawPath(path)
painter.drawText(self.m_textRect, self.m_text)
def mousePressEvent(self, event: QGraphicsSceneMouseEvent):
event.setAccepted(True)
def mouseMoveEvent(self, event: QGraphicsSceneMouseEvent):
if event.buttons() & Qt.LeftButton:
self.setPos(self.mapToParent(event.pos() - event.buttonDownPos(Qt.LeftButton)))
event.setAccepted(True)
else:
event.setAccepted(False)
class View(QGraphicsView):
def __init__(self, parent=None):
super().__init__(parent)
self.m_callouts: List[Callout] = []
self.setDragMode(QGraphicsView.NoDrag)
self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
# chart
self.m_chart = QChart(parent)
self.m_chart.setMinimumSize(640, 480)
self.m_chart.setTitle("Hover the line to show callout. Click the line to make it stay")
self.m_chart.legend().hide()
series = QLineSeries()
series.append(1, 3)
series.append(4, 5)
series.append(5, 4.5)
series.append(7, 1)
series.append(11, 2)
self.m_chart.addSeries(series)
series2 = QSplineSeries()
series2.append(1.6, 1.4)
series2.append(2.4, 3.5)
series2.append(3.7, 2.5)
series2.append(7, 4)
series2.append(10, 2)
self.m_chart.addSeries(series2)
self.m_chart.createDefaultAxes()
self.m_chart.setAcceptHoverEvents(True)
self.setRenderHint(QPainter.Antialiasing)
self.setScene(QGraphicsScene())
self.scene().addItem(self.m_chart)
self.m_coordX = QGraphicsSimpleTextItem(self.m_chart)
self.m_coordX.setPos(self.m_chart.size().width() / 2 - 50, self.m_chart.size().height() - 20)
self.m_coordX.setText("X: ")
self.m_coordY = QGraphicsSimpleTextItem(self.m_chart)
self.m_coordY.setPos(self.m_chart.size().width() / 2 + 50, self.m_chart.size().height() - 20)
self.m_coordY.setText("Y: ")
self.m_tooltip = Callout(self.m_chart)
self.scene().addItem(self.m_tooltip)
series.clicked.connect(self.keep_callout)
series.hovered.connect(self.tooltip)
series2.clicked.connect(self.keep_callout)
series2.hovered.connect(self.tooltip)
self.setMouseTracking(True)
def resizeEvent(self, event: QResizeEvent):
if scene := self.scene():
scene.setSceneRect(QRectF(QPointF(0, 0), QSizeF(event.size())))
self.m_chart.resize(QSizeF(event.size()))
self.m_coordX.setPos(self.m_chart.size().width() / 2 - 50, self.m_chart.size().height() - 20)
self.m_coordY.setPos(self.m_chart.size().width() / 2 + 50, self.m_chart.size().height() - 20)
for callout in self.m_callouts:
callout.updateGeometry()
super().resizeEvent(event)
def mouseMoveEvent(self, event: QMouseEvent):
from_chart = self.m_chart.mapToValue(event.pos())
self.m_coordX.setText(f"X: {from_chart.x()}")
self.m_coordX.setText(f"Y: {from_chart.y()}")
super().mouseMoveEvent(event)
def keep_callout(self):
self.m_callouts.append(self.m_tooltip)
self.m_tooltip = Callout(self.m_chart)
self.scene().addItem(self.m_tooltip)
def tooltip(self, point: QPointF, state: bool):
if not self.m_tooltip:
self.m_tooltip = Callout(self.m_chart)
if state:
self.m_tooltip.setText(f"X: {point.x()} \nY: {point.x()} ")
self.m_tooltip.m_anchor = point
self.m_tooltip.setZValue(11)
self.m_tooltip.updateGeometry()
self.m_tooltip.show()
else:
self.m_tooltip.hide()
if __name__ == '__main__':
app = QApplication(sys.argv)
window = View()
window.resize(640, 480)
window.show()
sys.exit(app.exec_())