import io
import sys
from PyQt5.QtWidgets import QWidget, QApplication, QShortcut, QVBoxLayout
from PyQt5.QtCore import QMimeData
from PyQt5.QtGui import QKeySequence

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure

import random

class Window(QWidget):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)
        self.figure = Figure()

        data = [random.random() for _ in range(10)]

        ax = self.figure.add_subplot(111)
        ax.plot(data, '*-',label='RandomData')
        legend = ax.legend()
        
        self.canvas = FigureCanvas(self.figure)
        self.canvas.draw()

        legend.set_draggable(True,use_blit=True) # Dragging is not ok in smaller figure/ ok in normal figure
        # legend.set_draggable(True) # Dragging is ok in smaller figure when blitting is off


        ctc = QShortcut(QKeySequence("Ctrl+C"), self)
        ctc.activated.connect(self.copy_to_clipboard)

        layout = QVBoxLayout()
        layout.addWidget(self.canvas)
        self.setLayout(layout)

    def copy_to_clipboard(self):
        fig = self.canvas.figure
        fig.set_size_inches(6,4)
        buf = io.BytesIO()
        fig.savefig(buf,dpi=300,transparent=True,bbox_inches='tight')
        mimeData = QMimeData()
        mimeData.setData("PNG",buf.getvalue())
        QApplication.clipboard().setMimeData(mimeData)
        buf.close()

    
if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = Window()
    main.showMaximized()
    sys.exit(app.exec_())