plot_view.py

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# Software License Agreement (BSD License)
#
# Copyright (c) 2014, Austin Hendrix, Stanford University
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
#  * Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#  * Redistributions in binary form must reproduce the above
#    copyright notice, this list of conditions and the following
#    disclaimer in the documentation and/or other materials provided
#    with the distribution.
#  * Neither the name of Willow Garage, Inc. nor the names of its
#    contributors may be used to endorse or promote products derived
#    from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

# Design notes:
#
# The original rxbag plot widget displays the plot
#
# It has a settings menu which allows the user to add subplots
#  and assign arbitrary fields to subplots. possibly many fields in a single
#  subplot, or one field per subplot, or any othe rcombination
#  in particular, it is possible to add the same field to multiple subplots
# It doesn't appear able to add fields from different topics to the same plot
#  Since rqt_plot can do this, and it's useful for our application, it's worth
#  thinking about. If it makes the UI too cluttered, it may not be worth it
#  If it isn't possible due to the architecture of rqt_bag, it may not be
#  worth it
#
# Thoughts on new design:
#  a plottable field is anything which is either numeric, or contains
#  at least one plottable subfield (this is useful for enabling/disabling all
#  of the fields of a complex type)
#
#  for simple messages, we could display a tree view of the message fields
#  on top of the plot, along with the color for each plottable field. This gets
#  unweildy for large messages, because they'll use up too much screen space
#  displaying the topic list
#
#  It may be better to display the topic list for a plot as a dockable widget,
#  and be able to dismiss it when it isn't actively in use, similar to the
#  existing rxbag plot config window
#
#  The plot should be dockable and viewable. If it's a separate window, it
#  doesn't make sense to make it align with the timeline. This could be done
#  if someone wanted to implement a separate timeline view

import os
import math
import codecs
import threading
import rospkg
from rqt_bag import MessageView

from python_qt_binding import loadUi
from python_qt_binding.QtCore import Qt, qWarning, Signal
from python_qt_binding.QtGui import QDoubleValidator, QIcon
from python_qt_binding.QtWidgets import QWidget, QPushButton, QTreeWidget, QTreeWidgetItem, QSizePolicy

from rqt_plot.data_plot import DataPlot

# rospy used for Time and Duration objects, for interacting with rosbag
import rospy

class PlotView(MessageView):
    """
    Popup plot viewer
    """
    name = 'Plot'

    def __init__(self, timeline, parent, topic):
        super(PlotView, self).__init__(timeline, topic)

        self.plot_widget = PlotWidget(timeline, parent, topic)

        parent.layout().addWidget(self.plot_widget)

    def message_viewed(self, bag, msg_details):
        """
        refreshes the plot
        """
        _, msg, t = msg_details[:3]

        if t is None:
            self.message_cleared()
        else:
            self.plot_widget.message_tree.set_message(msg)
            self.plot_widget.set_cursor((t-self.plot_widget.start_stamp).to_sec())

    def message_cleared(self):
        pass

class PlotWidget(QWidget):

    def __init__(self, timeline, parent, topic):
        super(PlotWidget, self).__init__(parent)
        self.setObjectName('PlotWidget')

        self.timeline = timeline
        msg_type = self.timeline.get_datatype(topic)
        self.msgtopic = topic
        self.start_stamp = self.timeline._get_start_stamp()
        self.end_stamp = self.timeline._get_end_stamp()

        # the current region-of-interest for our bag file
        # all resampling and plotting is done with these limits
        self.limits = [0,(self.end_stamp-self.start_stamp).to_sec()]

        rp = rospkg.RosPack()
        ui_file = os.path.join(rp.get_path('rqt_bag_plugins'), 'resource', 'plot.ui')
        loadUi(ui_file, self)
        self.message_tree = MessageTree(msg_type, self)
        self.data_tree_layout.addWidget(self.message_tree)
        # TODO: make this a dropdown with choices for "Auto", "Full" and
        #       "Custom"
        #       I continue to want a "Full" option here
        self.auto_res.stateChanged.connect(self.autoChanged)

        self.resolution.editingFinished.connect(self.settingsChanged)
        self.resolution.setValidator(QDoubleValidator(0.0,1000.0,6,self.resolution))


        self.timeline.selected_region_changed.connect(self.region_changed)

        self.recompute_timestep()

        self.plot = DataPlot(self)
        self.plot.set_autoscale(x=False)
        self.plot.set_autoscale(y=DataPlot.SCALE_VISIBLE)
        self.plot.autoscroll(False)
        self.plot.set_xlim(self.limits)
        self.data_plot_layout.addWidget(self.plot)

        self._home_button = QPushButton()
        self._home_button.setToolTip("Reset View")
        self._home_button.setIcon(QIcon.fromTheme('go-home'))
        self._home_button.clicked.connect(self.home)
        self.plot_toolbar_layout.addWidget(self._home_button)

        self._config_button = QPushButton("Configure Plot")
        self._config_button.clicked.connect(self.plot.doSettingsDialog)
        self.plot_toolbar_layout.addWidget(self._config_button)

        self.set_cursor(0)

        self.paths_on = set()
        self._lines = None

        # get bag from timeline
        bag = None
        start_time = self.start_stamp
        while bag is None:
            bag,entry = self.timeline.get_entry(start_time, topic)
            if bag is None:
                start_time = self.timeline.get_entry_after(start_time)[1].time

        self.bag = bag
        # get first message from bag
        msg = bag._read_message(entry.position)
        self.message_tree.set_message(msg[1])

        # state used by threaded resampling
        self.resampling_active = False
        self.resample_thread = None
        self.resample_fields = set()

    def set_cursor(self, position):
        self.plot.vline(position, color=DataPlot.RED)
        self.plot.redraw()

    def add_plot(self, path):
        self.resample_data([path])

    def update_plot(self):
        if len(self.paths_on)>0:
            self.resample_data(self.paths_on)

    def remove_plot(self, path):
        self.plot.remove_curve(path)
        self.paths_on.remove(path)
        self.plot.redraw()

    def load_data(self):
        """get a generator for the specified time range on our bag"""
        return self.bag.read_messages(self.msgtopic,
                self.start_stamp+rospy.Duration.from_sec(self.limits[0]),
                self.start_stamp+rospy.Duration.from_sec(self.limits[1]))

    def resample_data(self, fields):
        if self.resample_thread:
            # cancel existing thread and join
            self.resampling_active = False
            self.resample_thread.join()

        for f in fields:
            self.resample_fields.add(f)

        # start resampling thread
        self.resampling_active = True
        self.resample_thread = threading.Thread(target=self._resample_thread)
        # explicitly mark our resampling thread as a daemon, because we don't
        # want to block program exit on a long resampling operation
        self.resample_thread.setDaemon(True)
        self.resample_thread.start()

    def _resample_thread(self):
        # TODO:
        # * look into doing partial display updates for long resampling 
        #   operations
        # * add a progress bar for resampling operations
        x = {}
        y = {}
        for path in self.resample_fields:
            x[path] = []
            y[path] = []

        # bag object is not thread-safe; lock it while we resample
        with self.timeline._bag_lock:
            try:
                msgdata = self.load_data()
            except ValueError:
                # bag is closed or invalid; we're done here
                self.resampling_active = False
                return

            for entry in msgdata:
                # detect if we're cancelled and return early
                if not self.resampling_active:
                    return

                for path in self.resample_fields:
                    # this resampling method is very unstable, because it picks
                    # representative points rather than explicitly representing
                    # the minimum and maximum values present within a sample
                    # If the data has spikes, this is particularly bad because they
                    # will be missed entirely at some resolutions and offsets
                    if x[path]==[] or (entry[2]-self.start_stamp).to_sec()-x[path][-1] >= self.timestep:
                        y_value = entry[1]
                        for field in path.split('.'):
                            index = None
                            if field.endswith(']'):
                                field = field[:-1]
                                field, _, index = field.rpartition('[')
                            y_value = getattr(y_value, field)
                            if index:
                                index = int(index)
                                y_value = y_value[index]
                        y[path].append(y_value)
                        x[path].append((entry[2]-self.start_stamp).to_sec())

                # TODO: incremental plot updates would go here...
                #       we should probably do incremental updates based on time;
                #       that is, push new data to the plot maybe every .5 or .1
                #       seconds
                #       time is a more useful metric than, say, messages loaded or
                #       percentage, because it will give a reasonable refresh rate
                #       without overloading the computer
                # if we had a progress bar, we could emit a signal to update it here

        # update the plot with final resampled data
        for path in self.resample_fields:
            if len(x[path]) < 1:
                qWarning("Resampling resulted in 0 data points for %s" % path)
            else:
                if path in self.paths_on:
                    self.plot.clear_values(path)
                    self.plot.update_values(path, x[path], y[path])
                else:
                    self.plot.add_curve(path, path, x[path], y[path])
                    self.paths_on.add(path)

        self.plot.redraw()

        self.resample_fields.clear()
        self.resampling_active = False

    def recompute_timestep(self):
        # this is only called if we think the timestep has changed; either
        # by changing the limits or by editing the resolution
        limits = self.limits
        if self.auto_res.isChecked():
            timestep = round((limits[1]-limits[0])/200.0,5)
        else:
            timestep = float(self.resolution.text())
        self.resolution.setText(str(timestep))
        self.timestep = timestep

    def region_changed(self, start, end):
        # this is the only place where self.limits is set
        limits = [ (start - self.start_stamp).to_sec(),
                   (end - self.start_stamp).to_sec() ]

        # cap the limits to the start and end of our bag file
        if limits[0]<0:
            limits = [0.0,limits[1]]
        if limits[1]>(self.end_stamp-self.start_stamp).to_sec():
            limits = [limits[0],(self.end_stamp-self.start_stamp).to_sec()]

        self.limits = limits

        self.recompute_timestep()
        self.plot.set_xlim(limits)
        self.plot.redraw()
        self.update_plot()

    def settingsChanged(self):
        # resolution changed. recompute the timestep and resample
        self.recompute_timestep()
        self.update_plot()

    def autoChanged(self, state):
        if state==2:
            # auto mode enabled. recompute the timestep and resample
            self.resolution.setDisabled(True) 
            self.recompute_timestep()
            self.update_plot()   
        else:
            # auto mode disabled. enable the resolution text box
            # no change to resolution yet, so no need to redraw
            self.resolution.setDisabled(False)

    def home(self):
        # TODO: re-add the button for this. It's useful for restoring the
        #       X and Y limits so that we can see all of the data
        #       effectively a "zoom all" button

        # reset the plot to our current limits
        self.plot.set_xlim(self.limits)
        # redraw the plot; this forces a Y autoscaling
        self.plot.redraw()



class MessageTree(QTreeWidget):
    def __init__(self, msg_type, parent):
        super(MessageTree, self).__init__(parent)
        self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
        self.setHeaderHidden(True)
        self.itemChanged.connect(self.handleChanged)
        self._msg_type = msg_type
        self._msg = None

        self._expanded_paths = None
        self._checked_states = set()
        self.plot_list = set()

        # populate the tree from the message type


    @property
    def msg(self):
        return self._msg

    def set_message(self, msg):
        # Remember whether items were expanded or not before deleting
        if self._msg:
            for item in self.get_all_items():
                path = self.get_item_path(item)
                if item.isExpanded():
                    self._expanded_paths.add(path)
                elif path in self._expanded_paths:
                    self._expanded_paths.remove(path)
                if item.checkState(0)==Qt.Checked:
                    self._checked_states.add(path)
                elif path in self._checked_states:
                    self._checked_states.remove(path)
            self.clear()
        if msg:
            # Populate the tree
            self._add_msg_object(None, '', '', msg, msg._type)

            if self._expanded_paths is None:
                self._expanded_paths = set()
            else:
                # Expand those that were previously expanded, and collapse any paths that we've seen for the first time
                for item in self.get_all_items():
                    path = self.get_item_path(item)
                    if path in self._expanded_paths:
                        item.setExpanded(True)
                    else:
                        item.setExpanded(False)
        self._msg = msg
        self.update()

    def get_item_path(self, item):
        return item.data(0, Qt.UserRole)[0].replace(' ', '')  # remove spaces that may get introduced in indexing, e.g. [  3] is [3]

    def get_all_items(self):
        items = []
        try:
            root = self.invisibleRootItem()
            self.traverse(root, items.append)
        except Exception:
            # TODO: very large messages can cause a stack overflow due to recursion
            pass
        return items

    def traverse(self, root, function):
        for i in range(root.childCount()):
            child = root.child(i)
            function(child)
            self.traverse(child, function)

    def _add_msg_object(self, parent, path, name, obj, obj_type):
        label = name

        if hasattr(obj, '__slots__'):
            subobjs = [(slot, getattr(obj, slot)) for slot in obj.__slots__]
        elif type(obj) in [list, tuple]:
            len_obj = len(obj)
            if len_obj == 0:
                subobjs = []
            else:
                w = int(math.ceil(math.log10(len_obj)))
                subobjs = [('[%*d]' % (w, i), subobj) for (i, subobj) in enumerate(obj)]
        else:
            subobjs = []

        plotitem=False
        if type(obj) in [int, long, float]:
            plotitem=True
            if type(obj) == float:
                obj_repr = '%.6f' % obj
            else:
                obj_repr = str(obj)

            if obj_repr[0] == '-':
                label += ': %s' % obj_repr
            else:
                label += ':  %s' % obj_repr

        elif type(obj) in [str, bool, int, long, float, complex, rospy.Time]:
            # Ignore any binary data
            obj_repr = codecs.utf_8_decode(str(obj), 'ignore')[0]

            # Truncate long representations
            if len(obj_repr) >= 50:
                obj_repr = obj_repr[:50] + '...'

            label += ': ' + obj_repr
        item = QTreeWidgetItem([label])
        if name == '':
            pass
        elif path.find('.') == -1 and path.find('[') == -1:
            self.addTopLevelItem(item)
        else:
            parent.addChild(item)
        if plotitem == True:
            if path.replace(' ', '') in self._checked_states:
                item.setCheckState (0, Qt.Checked)
            else:
                item.setCheckState (0, Qt.Unchecked)
        item.setData(0, Qt.UserRole, (path, obj_type))


        for subobj_name, subobj in subobjs:
            if subobj is None:
                continue

            if path == '':
                subpath = subobj_name  # root field
            elif subobj_name.startswith('['):
                subpath = '%s%s' % (path, subobj_name)  # list, dict, or tuple
            else:
                subpath = '%s.%s' % (path, subobj_name)  # attribute (prefix with '.')

            if hasattr(subobj, '_type'):
                subobj_type = subobj._type
            else:
                subobj_type = type(subobj).__name__

            self._add_msg_object(item, subpath, subobj_name, subobj, subobj_type)

    def handleChanged(self, item, column):
        if item.data(0, Qt.UserRole)==None:
            pass
        else:
            path = self.get_item_path(item)
            if item.checkState(column) == Qt.Checked:
                if path not in self.plot_list:
                    self.plot_list.add(path)
                    self.parent().parent().parent().add_plot(path)
            if item.checkState(column) == Qt.Unchecked:
                if path in self.plot_list:
                    self.plot_list.remove(path)
                    self.parent().parent().parent().remove_plot(path)