图例示例¶
此示例展示了如何将图例从图表中分离以及如何将其重新附加回去。
默认情况下，图表会在与图表相同的视图中绘制图例。在某些情况下，用户可能希望将图例绘制到其他地方。为了实现这一点，图例可以从图表中分离出来。分离意味着图表不会绘制图例或尝试更改其布局。分离后的图例可以绘制在用户希望的任何地方，例如在不同的图形场景中。可以通过运行图例示例来检查图例的行为。在示例中，我们使用条形系列，在其中添加或删除条形集。图例反映了系列中的变化。图例可以分离或重新附加到图表上，并且可以修改其对齐方式。当图例分离时，可以自由调整大小和位置。
# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations
"""PySide6 port of the Legend example from Qt v5.x"""
import sys
from PySide6.QtCore import Qt, QRectF, Slot
from PySide6.QtGui import QBrush, QColor, QPainter, QPen
from PySide6.QtWidgets import (QApplication, QDoubleSpinBox,
QFormLayout, QGridLayout, QGroupBox,
QPushButton, QWidget)
from PySide6.QtCharts import QBarSeries, QBarSet, QChart, QChartView
class MainWidget(QWidget):
def __init__(self, parent=None):
super().__init__(parent)
self.chart = QChart()
self.series = QBarSeries()
self.main_layout = QGridLayout()
self.button_layout = QGridLayout()
self.font_layout = QFormLayout()
self.font_size = QDoubleSpinBox()
self.legend_posx = QDoubleSpinBox()
self.legend_posy = QDoubleSpinBox()
self.legend_width = QDoubleSpinBox()
self.legend_height = QDoubleSpinBox()
self.detach_legend_button = QPushButton("Toggle attached")
self.detach_legend_button.clicked.connect(self.toggle_attached)
self.button_layout.addWidget(self.detach_legend_button, 0, 0)
self.add_set_button = QPushButton("add barset")
self.add_set_button.clicked.connect(self.add_barset)
self.button_layout.addWidget(self.add_set_button, 2, 0)
self.remove_barset_button = QPushButton("remove barset")
self.remove_barset_button.clicked.connect(self.remove_barset)
self.button_layout.addWidget(self.remove_barset_button, 3, 0)
self.align_button = QPushButton("Align (Bottom)")
self.align_button.clicked.connect(self.set_legend_alignment)
self.button_layout.addWidget(self.align_button, 4, 0)
self.bold_button = QPushButton("Toggle bold")
self.bold_button.clicked.connect(self.toggle_bold)
self.button_layout.addWidget(self.bold_button, 8, 0)
self.italic_button = QPushButton("Toggle italic")
self.italic_button.clicked.connect(self.toggle_italic)
self.button_layout.addWidget(self.italic_button, 9, 0)
self.legend_posx.valueChanged.connect(self.update_legend_layout)
self.legend_posy.valueChanged.connect(self.update_legend_layout)
self.legend_width.valueChanged.connect(self.update_legend_layout)
self.legend_height.valueChanged.connect(self.update_legend_layout)
legend_layout = QFormLayout()
legend_layout.addRow("HPos", self.legend_posx)
legend_layout.addRow("VPos", self.legend_posy)
legend_layout.addRow("Width", self.legend_width)
legend_layout.addRow("Height", self.legend_height)
self.legend_settings = QGroupBox("Detached legend")
self.legend_settings.setLayout(legend_layout)
self.button_layout.addWidget(self.legend_settings)
self.legend_settings.setVisible(False)
# Create chart view with the chart
self.chart_view = QChartView(self.chart, self)
# Create spinbox to modify font size
self.font_size.setValue(self.chart.legend().font().pointSizeF())
self.font_size.valueChanged.connect(self.font_size_changed)
self.font_layout.addRow("Legend font size", self.font_size)
# Create layout for grid and detached legend
self.main_layout.addLayout(self.button_layout, 0, 0)
self.main_layout.addLayout(self.font_layout, 1, 0)
self.main_layout.addWidget(self.chart_view, 0, 1, 3, 1)
self.setLayout(self.main_layout)
self.create_series()
def create_series(self):
self.add_barset()
self.add_barset()
self.add_barset()
self.add_barset()
self.chart.addSeries(self.series)
self.chart.setTitle("Legend detach example")
self.chart.createDefaultAxes()
self.chart.legend().setVisible(True)
self.chart.legend().setAlignment(Qt.AlignBottom)
self.chart_view.setRenderHint(QPainter.RenderHint.Antialiasing)
def show_legend_spinbox(self):
self.legend_settings.setVisible(True)
chart_viewrect = self.chart_view.rect()
self.legend_posx.setMinimum(0)
self.legend_posx.setMaximum(chart_viewrect.width())
self.legend_posx.setValue(150)
self.legend_posy.setMinimum(0)
self.legend_posy.setMaximum(chart_viewrect.height())
self.legend_posy.setValue(150)
self.legend_width.setMinimum(0)
self.legend_width.setMaximum(chart_viewrect.width())
self.legend_width.setValue(150)
self.legend_height.setMinimum(0)
self.legend_height.setMaximum(chart_viewrect.height())
self.legend_height.setValue(75)
def hide_legend_spinbox(self):
self.legend_settings.setVisible(False)
@Slot()
def toggle_attached(self):
legend = self.chart.legend()
if legend.isAttachedToChart():
legend.detachFromChart()
legend.setBackgroundVisible(True)
legend.setBrush(QBrush(QColor(128, 128, 128, 128)))
legend.setPen(QPen(QColor(192, 192, 192, 192)))
self.show_legend_spinbox()
self.update_legend_layout()
else:
legend.attachToChart()
legend.setBackgroundVisible(False)
self.hide_legend_spinbox()
self.update()
@Slot()
def add_barset(self):
series_count = self.series.count()
bar_set = QBarSet(f"set {series_count}")
delta = series_count * 0.1
bar_set.append([1 + delta, 2 + delta, 3 + delta, 4 + delta])
self.series.append(bar_set)
@Slot()
def remove_barset(self):
sets = self.series.barSets()
len_sets = len(sets)
if len_sets > 0:
self.series.remove(sets[len_sets - 1])
@Slot()
def set_legend_alignment(self):
button = self.sender()
legend = self.chart.legend()
alignment = legend.alignment()
if alignment == Qt.AlignTop:
legend.setAlignment(Qt.AlignLeft)
if button:
button.setText("Align (Left)")
elif alignment == Qt.AlignLeft:
legend.setAlignment(Qt.AlignBottom)
if button:
button.setText("Align (Bottom)")
elif alignment == Qt.AlignBottom:
legend.setAlignment(Qt.AlignRight)
if button:
button.setText("Align (Right)")
else:
if button:
button.setText("Align (Top)")
legend.setAlignment(Qt.AlignTop)
@Slot()
def toggle_bold(self):
legend = self.chart.legend()
font = legend.font()
font.setBold(not font.bold())
legend.setFont(font)
@Slot()
def toggle_italic(self):
legend = self.chart.legend()
font = legend.font()
font.setItalic(not font.italic())
legend.setFont(font)
@Slot()
def font_size_changed(self):
legend = self.chart.legend()
font = legend.font()
font_size = self.font_size.value()
if font_size < 1:
font_size = 1
font.setPointSizeF(font_size)
legend.setFont(font)
@Slot()
def update_legend_layout(self):
legend = self.chart.legend()
rect = QRectF(self.legend_posx.value(), self.legend_posy.value(),
self.legend_width.value(), self.legend_height.value())
legend.setGeometry(rect)
legend.update()
if __name__ == "__main__":
app = QApplication(sys.argv)
w = MainWidget()
available_geometry = w.screen().availableGeometry()
size = available_geometry.height() * 0.75
w.setFixedSize(size, size)
w.show()
sys.exit(app.exec())