在带有PyQt和matplotlib的可滚动小部件中显示多个图 [英] Show several plots in a scrollable widget with PyQt and matplotlib

问题描述

因为我没有得到这个问题的答案我尝试用PyQt解决它. 显然，当涉及到QScrollArea时，这并不容易...

Since I didn't get an answer for this question I tried solving it with PyQt. Apparently, it's not that easy, when QScrollArea is involved...

我写了一个小测试，基本上可以满足我的需求，但是并没有像我期望的那样显示滚动区域和其中的绘图:

I wrote a small test that basically does what I'm looking for, but it's not showing the scroll area and the plots inside it as I expected:

from PyQt4 import QtCore, QtGui
import os,sys

#import matplotlib
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QTAgg as NavigationToolbar
from matplotlib.figure import Figure

qapp = QtGui.QApplication(sys.argv)
qwidget = QtGui.QWidget()
qwidget.setGeometry(QtCore.QRect(0, 0, 500, 500))
qlayout = QtGui.QHBoxLayout(qwidget)
qwidget.setLayout(qlayout)

qscroll = QtGui.QScrollArea(qwidget)
qscroll.setGeometry(QtCore.QRect(0, 0, 500, 500))
qscroll.setFrameStyle(QtGui.QFrame.NoFrame)
qlayout.addWidget(qscroll)

qscrollContents = QtGui.QWidget()
qscrollLayout = QtGui.QVBoxLayout(qscrollContents)
qscrollLayout.setGeometry(QtCore.QRect(0, 0, 1000, 1000))

qscroll.setWidget(qscrollContents)
qscroll.setWidgetResizable(True)

for i in xrange(5):
  qfigWidget = QtGui.QWidget(qscrollContents)
  fig = Figure((5.0, 4.0), dpi=100)
  canvas = FigureCanvas(fig)
  canvas.setParent(qfigWidget)
  toolbar = NavigationToolbar(canvas, qfigWidget)
  axes = fig.add_subplot(111)
  axes.plot([1,2,3,4])
  qscrollLayout.addWidget(qfigWidget)

qscrollContents.setLayout(qscrollLayout)

qwidget.show()
exit(qapp.exec_()) 

谁能解释为什么它不起作用?

Can anyone explain why it's not working?

推荐答案

您正在为每个图创建一个QWidget.但是您不能通过布局将canvas或toolbar放入其中，因此它们无法与QWidget传达尺寸信息.默认情况下，QWidget没有minimumSize，并且QScrollArea内的小部件/布局可以使其尽可能小，以适应可用空间(QScrollArea的大小).

You are creating a QWidget for each plot. But you don't put your canvas or toolbar in it via a layout, so they can't communicate the size information with the QWidget. By default, a QWidget has no minimumSize and the widget/layout inside the QScrollArea can make them as small as it wants in order to fit the available space (which is the size of QScrollArea).

通过布局添加图会有所帮助，但是我发现FigureCanvas小部件也没有任何最小尺寸，因此可以缩小.要快速修复，可以设置minimumSize.具有这些修复程序的循环部分应如下所示:

Adding plots via layout helps, but I find that the FigureCanvas widget also doesn't have any minimum size so it can shrink. For a quick fix, you can set a minimumSize. The loop part with these fixes should look like this:

for i in xrange(5):
  qfigWidget = QtGui.QWidget(qscrollContents)

  fig = Figure((5.0, 4.0), dpi=100)
  canvas = FigureCanvas(fig)
  canvas.setParent(qfigWidget)
  toolbar = NavigationToolbar(canvas, qfigWidget)
  axes = fig.add_subplot(111)
  axes.plot([1,2,3,4])

  # place plot components in a layout
  plotLayout = QtGui.QVBoxLayout()
  plotLayout.addWidget(canvas)
  plotLayout.addWidget(toolbar)
  qfigWidget.setLayout(plotLayout)

  # prevent the canvas to shrink beyond a point
  # original size looks like a good minimum size
  canvas.setMinimumSize(canvas.size())

  qscrollLayout.addWidget(qfigWidget)

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