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