multiplotwidget.py

   1 ##
   2 ## This file is part of the sigrok-meter project.
   3 ##
   4 ## Copyright (C) 2015 Jens Steinhauser <jens.steinhauser@gmail.com>
   5 ##
   6 ## This program is free software; you can redistribute it and/or modify
   7 ## it under the terms of the GNU General Public License as published by
   8 ## the Free Software Foundation; either version 2 of the License, or
   9 ## (at your option) any later version.
  10 ##
  11 ## This program is distributed in the hope that it will be useful,
  12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ## GNU General Public License for more details.
  15 ##
  16 ## You should have received a copy of the GNU General Public License
  17 ## along with this program; if not, write to the Free Software
  18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19 ##
  20
  21 import qtcompat
  22
  23 QtCore = qtcompat.QtCore
  24 QtGui = qtcompat.QtGui
  25 pyqtgraph = qtcompat.pyqtgraph
  26
  27 # black foreground on white background
  28 pyqtgraph.setConfigOption('background', 'w')
  29 pyqtgraph.setConfigOption('foreground', 'k')
  30
  31 class Plot(object):
  32     '''Helper class to keep all graphics items of a plot together.'''
  33
  34     def __init__(self, view, xaxis, yaxis):
  35         self.view = view
  36         self.xaxis = xaxis
  37         self.yaxis = yaxis
  38         self.visible = False
  39
  40 class MultiPlotItem(pyqtgraph.GraphicsWidget):
  41
  42     # Emitted when a plot is shown.
  43     plotShown = QtCore.Signal()
  44
  45     # Emitted when a plot is hidden by the user via the context menu.
  46     plotHidden = QtCore.Signal(Plot)
  47
  48     def __init__(self, parent=None):
  49         pyqtgraph.GraphicsWidget.__init__(self, parent)
  50
  51         self.setLayout(QtGui.QGraphicsGridLayout())
  52         self.layout().setContentsMargins(10, 10, 10, 1)
  53         self.layout().setHorizontalSpacing(0)
  54         self.layout().setVerticalSpacing(0)
  55
  56         for i in range(2):
  57             self.layout().setColumnPreferredWidth(i, 0)
  58             self.layout().setColumnMinimumWidth(i, 0)
  59             self.layout().setColumnSpacing(i, 0)
  60
  61         self.layout().setColumnStretchFactor(0, 0)
  62         self.layout().setColumnStretchFactor(1, 100)
  63
  64         # List of 'Plot' objects that are shown.
  65         self._plots = []
  66
  67         self._hideActions = {}
  68
  69     def addPlot(self):
  70         '''Adds and returns a new plot.'''
  71
  72         row = self.layout().rowCount()
  73
  74         view = pyqtgraph.ViewBox(parent=self)
  75
  76         # If this is not the first plot, link to the axis of the previous one.
  77         if self._plots:
  78             view.setXLink(self._plots[-1].view)
  79
  80         yaxis = pyqtgraph.AxisItem(parent=self, orientation='left')
  81         yaxis.linkToView(view)
  82         yaxis.setGrid(255)
  83
  84         xaxis = pyqtgraph.AxisItem(parent=self, orientation='bottom')
  85         xaxis.linkToView(view)
  86         xaxis.setGrid(255)
  87
  88         plot = Plot(view, xaxis, yaxis)
  89         self._plots.append(plot)
  90
  91         self.showPlot(plot)
  92
  93         # Create a separate action object for each plots context menu, so that
  94         # we can later find out which plot should be hidden by looking at
  95         # 'self._hideActions'.
  96         hideAction = QtGui.QAction('Hide', self)
  97         hideAction.triggered.connect(self._onHideActionTriggered)
  98         self._hideActions[id(hideAction)] = plot
  99         view.menu.insertAction(view.menu.actions()[0], hideAction)
 100
 101         return plot
 102
 103     def _rowNumber(self, plot):
 104         '''Returns the number of the first row a plot occupies.'''
 105
 106         # Every plot takes up two rows
 107         return 2 * self._plots.index(plot)
 108
 109     @QtCore.Slot()
 110     def _onHideActionTriggered(self, checked=False):
 111         # The plot that we want to hide.
 112         plot = self._hideActions[id(self.sender())]
 113         self.hidePlot(plot)
 114
 115     def hidePlot(self, plot):
 116         '''Hides 'plot'.'''
 117
 118         # Only hiding wouldn't give up the space occupied by the items,
 119         # we have to remove them from the layout.
 120         self.layout().removeItem(plot.view)
 121         self.layout().removeItem(plot.xaxis)
 122         self.layout().removeItem(plot.yaxis)
 123
 124         plot.view.hide()
 125         plot.xaxis.hide()
 126         plot.yaxis.hide()
 127
 128         row = self._rowNumber(plot)
 129         self.layout().setRowStretchFactor(row,     0)
 130         self.layout().setRowStretchFactor(row + 1, 0)
 131
 132         plot.visible = False
 133         self.plotHidden.emit(plot)
 134
 135     def showPlot(self, plot):
 136         '''Adds the items of the plot to the scene's layout and makes
 137         them visible.'''
 138
 139         if plot.visible:
 140             return
 141
 142         row = self._rowNumber(plot)
 143         self.layout().addItem(plot.yaxis, row,     0, QtCore.Qt.AlignRight)
 144         self.layout().addItem(plot.view,  row,     1)
 145         self.layout().addItem(plot.xaxis, row + 1, 1)
 146
 147         plot.view.show()
 148         plot.xaxis.show()
 149         plot.yaxis.show()
 150
 151         for i in range(row, row + 2):
 152             self.layout().setRowPreferredHeight(i, 0)
 153             self.layout().setRowMinimumHeight(i, 0)
 154             self.layout().setRowSpacing(i, 0)
 155
 156         self.layout().setRowStretchFactor(row,     100)
 157         self.layout().setRowStretchFactor(row + 1,   0)
 158
 159         plot.visible = True
 160         self.plotShown.emit()
 161
 162 class MultiPlotWidget(pyqtgraph.GraphicsView):
 163     '''Widget that aligns multiple plots on top of each other.
 164
 165     (The built in classes fail at doing this correctly when the axis grow,
 166     just try zooming in the "GraphicsLayout" or the "Linked View" examples.)'''
 167
 168     def __init__(self, parent=None):
 169         pyqtgraph.GraphicsView.__init__(self, parent)
 170
 171         self.multiPlotItem = MultiPlotItem()
 172         self.setCentralItem(self.multiPlotItem)
 173
 174         for m in [
 175             'addPlot',
 176             'hidePlot',
 177             'showPlot'
 178         ]:
 179             setattr(self, m, getattr(self.multiPlotItem, m))
 180
 181         self.multiPlotItem.plotShown.connect(self._on_plotShown)
 182
 183         # Expose the signal of the plot item.
 184         self.plotHidden = self.multiPlotItem.plotHidden
 185
 186     def _on_plotShown(self):
 187         # This call is needed if only one plot exists and it was hidden,
 188         # without it the layout would start acting weird and not make the
 189         # MultiPlotItem fill the view widget after showing the plot again.
 190         self.resizeEvent(None)