I have a library of draggable matplotlib objects that I'm trying to utilize with a PyQt5 GUI. The objects' event listeners function correctly in a standalone matplotlib figure window but do not function when the figure is embedded in a QT widget. Both plots render correctly and there are no error messages when I try to drag the patch in the QT widget.
Object MCVE:
import matplotlib.patches as patches
class _DragObj:
def __init__(self, ax):
self.parentcanvas = ax.figure.canvas
self.parentax = ax
self.clickpress = self.parentcanvas.mpl_connect('button_press_event', self.on_click)
self.clicked = False
def on_click(self, event):
if event.inaxes != self.parentax: return
self.mousemotion = self.parentcanvas.mpl_connect('motion_notify_event', self.on_motion)
self.clickrelease = self.parentcanvas.mpl_connect('button_release_event', self.on_release)
self.clickx = event.xdata
self.clicky = event.ydata
self.clicked = True
def on_release(self, event):
self.clicked = False
self.disconnect()
def disconnect(self):
self.parentcanvas.mpl_disconnect(self.mousemotion)
self.parentcanvas.mpl_disconnect(self.clickrelease)
self.parentcanvas.draw()
def stopdrag(self):
self.myobj.set_url('')
self.parentcanvas.mpl_disconnect(self.clickpress)
class _DragPatch(_DragObj):
def __init__(self, ax, xy):
super().__init__(ax)
self.oldxy = xy
def on_motion(self, event):
if not self.clicked: return
if event.inaxes != self.parentax: return
oldx, oldy = self.oldxy
dx = event.xdata - self.clickx
dy = event.ydata - self.clicky
newxy = [oldx + dx, oldy + dy]
self.myobj.xy = newxy
self.parentcanvas.draw()
def on_release(self, event):
self.clicked = False
self.oldxy = self.myobj.xy
self.disconnect()
class DragRectangle(_DragPatch):
def __init__(self, ax, xy, width, height, angle=0.0, **kwargs):
self.myobj = patches.Rectangle(xy, width, height, angle, **kwargs)
ax.add_artist(self.myobj)
super().__init__(ax, xy)
The functioning matplotlib example:
import minidrag
import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.add_subplot(111)
rect = minidrag.DragRectangle(ax, (0, 0), 2, 1)
ax.set_xlim(-5, 5)
ax.set_ylim(-5, 5)
plt.show()
The nonfunctional PyQT example:
import sys
from PyQt5 import QtWidgets as QtW
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar
from matplotlib.figure import Figure
import minidrag
class windowGUI(QtW.QDialog):
def __init__(self):
super().__init__()
# Set up figure
width_px = 800
height_px = 600
rect = QtW.QDesktopWidget().availableGeometry()
screenrez = (rect.width(), rect.height())
left_px = (screenrez[0] - width_px)/2
top_px = (screenrez[1] - height_px)/2
self.setGeometry(left_px, top_px, width_px, height_px)
self.canvas = PlotCanvas()
layout = QtW.QVBoxLayout()
layout.addWidget(NavigationToolbar(self.canvas, self))
layout.addWidget(self.canvas)
self.setLayout(layout)
class PlotCanvas(FigureCanvas):
def __init__(self):
fig = Figure(frameon=False)
super().__init__(fig)
super().setSizePolicy(QtW.QSizePolicy.Expanding, QtW.QSizePolicy.Expanding)
super().updateGeometry()
ax = fig.add_subplot(111)
rect = minidrag.DragRectangle(ax, (0, 0), 2, 1)
ax.set_xlim(-5, 5)
ax.set_ylim(-5, 5)
app = QtW.QApplication(sys.argv)
window = windowGUI()
window.show()
sys.exit(app.exec_())
I'm using Python 3.6.0, matplotlib (2.0.0), and PyQt5 (5.8)
What am I missing?
def dragEnterEvent(self, event): event.acceptProposedAction()for all the embeddingQWidgets? Otherwise the event can't propagate to the embedded widget. Btw you might need to do the same fordropEvent. See QWidget.dragEnterEvent.setAcceptDrops(True)(at least the corresponding property isFalseby default; see the C++ docs). You might also want to read the C++ drag & drop docs for more information on how drag & drop works within Qt (the pyqt references sometimes are a bit sparse when it comes to more specific topics).