Statechart.py 22.4 KB
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#!/usr/bin/env python

"""
    OpenGEODE - A tiny, free SDL Editor for TASTE

    SDL is the Specification and Description Language (Z100 standard from ITU)

    Copyright (c) 2012-2013 European Space Agency

    Designed and implemented by Maxime Perrotin

    This module is responsible for the rendering of statecharts using
    the graphviz library.

    Credits:
    Rendering algorithm to transform graphviz b-splines to to Qt bezier curves
    was developed by Steve Dodier-Lazaro (www.mupuf.org)

    Contact: maxime.perrotin@esa.int
"""

import logging
import math
from PySide import QtGui, QtCore

try:
    import pygraphviz as dotgraph
except ImportError:
    print('pygraphviz not found. Statechart module will not work\n'
          'If you are using Debian (or Ubuntu) you can install it from\n'
          'the official repos: sudo apt-get install python-pygraphviz')

import genericSymbols

RENDER_DPI = {'X': 93.0, 'Y': 95.0}
G_SYMBOLS = set()
EDGES = []

LOG = logging.getLogger(__name__)


# pylint: disable=R0904
class Record(genericSymbols.HorizontalSymbol, object):
    ''' Graphviz node - it is floating and has no parent'''
    _unique_followers = []
    _insertable_followers = ['Record', 'Diamond']
    _terminal_followers = []
    textbox_alignment = (QtCore.Qt.AlignTop
                         | QtCore.Qt.AlignHCenter)

    def __init__(self, node, graph):
        ''' Initialization: compute the polygon shape '''
        self.name = node['name']
        super(Record, self).__init__(x=node['pos'][0],
                y=node['pos'][1], text=self.name)
        self.set_shape(node['width'], node['height'])
        self.setBrush(QtGui.QBrush(QtGui.QColor(255, 255, 202)))
        self.graph = graph
        if 'properties' in node:
            property_box = QtGui.QGraphicsTextItem(self)
            property_box.setPos(5, 30)
            property_box.setPlainText(node['properties'])
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        # Text in statecharts is read-only:
        self.text.setTextInteractionFlags(QtCore.Qt.TextBrowserInteraction)
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    def set_shape(self, width, height):
        ''' Define the polygon shape from width and height '''
        path = QtGui.QPainterPath()
        path.moveTo(0, 25)
        path.lineTo(width, 25)
        path.addRoundedRect(0, 0, width, height, 15, 15)
        self.setPath(path)
        super(Record, self).set_shape(width, height)

    def resize_item(self, _):
        ''' Redefine the resizing function - forbid resizing '''
        pass

    def __str__(self):
        ''' User-friendly information about the node '''
        return('Record ' + self.name + ' at pos ' + str(self.pos()) +
               ' bounding rect = ' + str(self.boundingRect()))

    def mouse_release(self, _):
        ''' After moving item, ask dot to recompute the edges '''
        # Discard mouse release default action (CAM, UndoCommand)
        pass


# pylint: disable=R0904
class Point(genericSymbols.HorizontalSymbol, object):
    ''' Graphviz point node - used for START transition'''
    _unique_followers = []
    _insertable_followers = ['Record', 'Diamond']
    _terminal_followers = []
    textbox_alignment = (QtCore.Qt.AlignTop
                         | QtCore.Qt.AlignHCenter)

    def __init__(self, node, graph):
        ''' Initialization: compute the polygon shape '''
        self.name = node['name']
        super(Point, self).__init__(x=node['pos'][0],
                y=node['pos'][1], text='')
        self.set_shape(node['width'], node['height'])
        self.setBrush(QtGui.QBrush(QtCore.Qt.black))
        self.graph = graph
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        # Text is read only
        self.text.setTextInteractionFlags(QtCore.Qt.TextBrowserInteraction)
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    def set_shape(self, width, height):
        ''' Define the polygon shape from width and height '''
        path = QtGui.QPainterPath()
        path.addEllipse(0, 0, width, height)
        self.setPath(path)
        super(Point, self).set_shape(width, height)

    def resize_item(self, _):
        ''' Redefine the resizing function - forbid resizing '''
        pass

    def __str__(self):
        ''' User-friendly information about the node '''
        return('Point ' + self.name + ' at pos ' + str(self.pos()) +
                ' bounding rect = ' + str(self.boundingRect()))

    def mouse_release(self, _):
        ''' After moving item, ask dot to recompute the edges '''
        #self.scene().refresh()
        update(self.scene())


# pylint: disable=R0904
class Diamond(genericSymbols.HorizontalSymbol, object):
    ''' Graphviz node - it is floating and has no parent'''
    _unique_followers = []
    _insertable_followers = ['Record']
    _terminal_followers = []
    textbox_alignment = (QtCore.Qt.AlignTop
                         | QtCore.Qt.AlignHCenter)

    def __init__(self, node, graph):
        ''' Initialization: compute the polygon shape '''
        self.name = node['name']
        super(Diamond, self).__init__(x=node['pos'][0],
                y=node['pos'][1], text='')
        self.set_shape(node['width'], node['height'])
        self.graph = graph

    def set_shape(self, width, height):
        ''' Define the polygon shape from width and height '''
        path = QtGui.QPainterPath()
        path.moveTo(width / 2, 0)
        path.lineTo(width, height / 2)
        path.lineTo(width / 2, height)
        path.lineTo(0, height / 2)
        path.lineTo(width / 2, 0)
        self.setPath(path)
        super(Diamond, self).set_shape(width, height)

    def resize_item(self, _):
        ''' Redefine the resizing function - forbid resizing '''
        pass

    def __str__(self):
        ''' User-friendly information about the node '''
        return('Node ' + self.name + ' at pos ' + str(self.pos()) +
                ' bounding rect = ' + str(self.boundingRect()))

    def mouse_release(self, _):
        ''' After moving item, ask dot to recompute the edges '''
        #update(self.scene())
        pass


class Controlpoint(QtGui.QGraphicsPathItem, object):
    ''' Class handling one edge control point (to change bezier curves) '''
    def __init__(self, pos, edge):
        ''' Set the original control point - with color, shape '''
        path = QtGui.QPainterPath()
        path.addEllipse(pos.x() - 5, pos.y() - 5, 10, 10)
        super(Controlpoint, self).__init__(path, parent=edge)
        self.setPen(QtGui.QColor(50, 100, 120, 200))
        self.setBrush(QtGui.QColor(200, 200, 210, 120))
        self.setFlags(QtGui.QGraphicsItem.ItemIsSelectable |
                      QtGui.QGraphicsItem.ItemIsMovable)
        self.edge = edge
        self.hide()

    @property
    def center(self):
        ''' Return the position of the center of the shape '''
        return self.pos() + self.boundingRect().center()

    def mouseMoveEvent(self, event):
        ''' When user moves a control point, update the connection shape '''
        super(Controlpoint, self).mouseMoveEvent(event)
        self.edge.reshape()


class Connectionpoint(Controlpoint, object):
    '''
        Class handling an end connection point - similar to Controlpoint,
        except the shape and the behaviour when moved. Connection point
        must check with its owning symbol if the move is valid.
    '''
    def __init__(self, pos, edge, symbol):
        ''' Create the point - as a small, lightblue box '''
        super(Connectionpoint, self).__init__(pos, edge=edge)
        path = QtGui.QPainterPath()
        path.addRect(0, 0, 10, 10)
        self.setPath(path)
        self.setPos(pos.x() - 5, pos.y() - 5)
        # Symbol actually owning the connection point
        self.symbol = symbol


    def update_position(self):
        '''
            Update the position of the end point so that it is always
            placed correctly on the symbol that contains it (but that may
            not be the parent of the point if is the end point)
            After the position update, reshape the edge so that the lines
            are properly drawn to the new position
        '''
        # Transform position to owning symbol coordinates:
        center_pos = self.scenePos() + self.boundingRect().center()
        pos_symb = self.symbol.mapFromScene(center_pos)

        # Ask to symbol the nearest valid position on its shape
        # to place the connection point, and adjust position
        nearest_x, nearest_y = self.symbol.closest_connection_point(pos_symb)

        self.moveBy(-nearest_x, -nearest_y)

        self.edge.reshape()

    def mouseMoveEvent(self, event):
        '''
            When user moves the point, check with the connected symbol
            where the actual connection point should be placed
        '''
        # calling super function moves to the new point
        super(Connectionpoint, self).mouseMoveEvent(event)
        # Then compute a valid position, based on the owning symbol
        self.update_position()


class Edge(genericSymbols.Connection, object):
    ''' B-spline/Bezier connection shape '''
    def __init__(self, edge, graph):
        ''' Set generic parameters from Connection class '''
        self.text_label = None
        super(Edge, self).__init__(edge['source'], edge['target'])
        self.edge = edge
        self.graph = graph

        # Initialize control point coordinates
        # Start and End points are optional - graphviz decision
        self.start_point = (self.mapFromScene(*self.edge['start']) if
                 self.edge.get('start') else None)
        self.end_point = (self.mapFromScene(*self.edge['end']) if
                 self.edge.get('end') else None)
        self.bezier = [self.mapFromScene(*self.edge['spline'][0])]
        # Bezier control points (groups of three points):
        assert(len(self.edge['spline']) % 3 == 1)
        for i in xrange(1, len(self.edge['spline']), 3):
            self.bezier.append([Controlpoint(
                          self.mapFromScene(*self.edge['spline'][i + j]), self)
                          for j in range(3)])
        # Set connection points as not visible, by default
        self.bezier_visible = False
        
        # Create connection points at start and end of the edge
        self.source_connection = Connectionpoint(
                self.start_point or self.bezier[0], self, self.parent)
        self.parent.movable_points.append(self.source_connection)
        self.end_connection = Connectionpoint(
                self.end_point or self.bezier[-1], self, self.child)
        self.child.movable_points.append(self.end_connection)
        self.reshape()

    def bezier_set_visible(self, visible=True):
        ''' Display or hide the edge control points '''
        self.bezier_visible = visible
        for group in self.bezier[1:]:
            for ctrl_point in group:
                if visible:
                    ctrl_point.show()
                else:
                    ctrl_point.hide()
        if visible:
            self.end_connection.show()
            self.source_connection.show()
        else:
            self.end_connection.hide()
            self.source_connection.hide()
        self.update()

    def mousePressEvent(self, event):
        ''' On a mouse click, display the control points '''
        self.bezier_set_visible(True)

   # pylint: disable=R0914
    def reshape(self):
        ''' Update the shape of the edge (redefined function) '''
        path = QtGui.QPainterPath()
        # If there is a starting point, draw a line to the first curve point
        if self.start_point:
            path.moveTo(self.source_connection.center) #start_point)
            path.lineTo(self.bezier[0])
        else:
            path.moveTo(self.source_connection.center)#bezier[0])
        # Loop over the curve points:
        for group in self.bezier[1:]:
            path.cubicTo(*[point.center for point in group])

        # If there is an ending point, draw a line to it
        if self.end_point:
            path.lineTo(self.end_connection.center) #end_point)

        # Draw the arrow head
        length = path.length()
        percent = path.percentAtLength(length - 10.0)
        src = path.pointAtPercent(percent)
        #angle = path.angleAtPercent(percent)
        #print angle
        end_point = path.currentPosition()
        line = QtCore.QLineF(src, end_point)
        angle = math.acos(line.dx() / line.length())
        if line.dy() >= 0:
            angle = math.pi * 2 - angle
        arrow_size = 10.0
        arrow_p1 = end_point + QtCore.QPointF(
                math.sin(angle - math.pi/3) * arrow_size,
                math.cos(angle - math.pi/3) * arrow_size)
        arrow_p2 = end_point + QtCore.QPointF(
                math.sin(angle - math.pi + math.pi/3) * arrow_size,
                math.cos(angle - math.pi + math.pi/3) * arrow_size)
        path.lineTo(arrow_p1)
        path.lineTo(end_point)
        path.lineTo(arrow_p2)
        path.moveTo(end_point)
        try:
            # Add the transition label, if any (none for the START edge)
            font = QtGui.QFont('arial', pointSize=8)
            width = QtGui.QFontMetrics(font).width(
                    self.edge.get('label', 0))
            pos = self.mapFromScene(*self.edge['lp'])
            #path.addText(pos.x() - width/2, pos.y(),
            #        font, self.edge['label'])
            if not self.text_label:
                self.text_label = QtGui.QGraphicsTextItem(
                                 self.edge.get('label', ''), parent=self)
            self.text_label.setX(pos.x() - width / 2)
            self.text_label.setY(pos.y())
            self.text_label.setFont(font)
            self.text_label.show()
        except KeyError:
            # no label
            pass
        self.setPath(path)


    def __str__(self):
        ''' user-friendly information about the edge coordinates '''
        return('Edge between ' + self.edge['source'].name + ' and ' +
                self.edge['target'].name + str(self.edge['spline'][0]))

    def paint(self, painter, option, widget):
        ''' Apply anti-aliasing to Edge Connections '''
        painter.setRenderHint(QtGui.QPainter.Antialiasing, True)
        super(Edge, self).paint(painter, option, widget)
        # Draw lines between connection points, if visible
        if self.bezier_visible:
            painter.setPen(
                    QtGui.QPen(QtCore.Qt.lightGray, 0, QtCore.Qt.SolidLine))
            painter.setBrush(QtCore.Qt.NoBrush)
            points_flat = [point.center
                           for sub1 in self.bezier[1:] for point in sub1]
            painter.drawPolyline([self.source_connection.center]
                                  + points_flat + [self.end_connection.center])

def edges(scene, node):
    ''' Return all edges of a given node '''
    for item in scene.items():
        if isinstance(item, Edge) and node in (
                item.edge['source'], item.edge['target']):
            yield item


# Front end part - use Graphviz to parse the input file and transform it
# pylint: disable=R0914
def preprocess_edges(my_graph, nodes, bounding_rect, dpi):
    ''' Parse edges and put them in a clean datastructure '''
    edges = []
    bb_height = bounding_rect[3]
    for edge in my_graph.edges_iter():
        new_edge = {}
        source, target = edge
        for node in nodes:
            if node.name == source:
                new_edge['source'] = node
            if node.name == target:
                new_edge['target'] = node
        new_edge['label'] = edge.attr.get('label')
        try:
            new_edge['lp'] = [float(val) for val in edge.attr['lp'].split(',')]
        except (ValueError, AttributeError):
            pass
        else:
            # translate the label position from dot-coordinates to Qt
            new_edge['lp'][0] *= RENDER_DPI['X'] / dpi
            new_edge['lp'][1] = (
                    bb_height - new_edge['lp'][1]) * (RENDER_DPI['Y'] / dpi)

        pos = edge.attr['pos'].split()

        if pos[0].startswith('e'):
            new_edge['end'] = [float(val)
                    for val in pos.pop(0).split(',')[1:]]
            # And translate position
            new_edge['end'][0] *= (RENDER_DPI['X'] / dpi)
            new_edge['end'][1] = (
                    bb_height - new_edge['end'][1]) * (RENDER_DPI['Y'] / dpi)

        elif pos[0].startswith('s'):
            new_edge['start'] = [float(val)
                    for val in pos.pop(0).split(',')[1:]]
            # And translate position
            new_edge['start'][0] *= (RENDER_DPI['X'] / dpi)
            new_edge['start'][1] = (
                    bb_height - new_edge['start'][1]) * (RENDER_DPI['Y'] / dpi)

        spline = []
        for entry in pos:
            point = [float(val) for val in entry.split(',')]
            point[0] *= (RENDER_DPI['X'] / dpi)
            point[1] = (bb_height - point[1]) * (RENDER_DPI['Y'] / dpi)

            spline.append(point)
        new_edge['spline'] = spline
        edges.append(new_edge)
    return edges


def preprocess_nodes(my_graph, bounding_rect, dpi):
    ''' Parse the nodes from the graph and create a clean datastructure '''
    # Graphviz calculates coordinates starting on the bottom-left corner,
    # while Qt uses the top-left corner, so we must translate all y-coord.
    bb_height = bounding_rect[3]
    nodes = []
    for node in my_graph.nodes_iter():
        new_node = {}
        # Get the node shape attribute - default is record
        new_node['shape'] = node.attr.get('shape') or 'record'
        # node main name
        new_node['name'] = str(node)
        try:
            # node complete label (can contain several compartments)
            properties = (
                    node.attr['label'][1:-2].split('|')[1].replace('\\', '\n'))
            new_node['properties'] = properties  # node.attr.get('label')
        except IndexError:
            pass
        # transform width and height from inches to pixels
        new_node['width'] = float(node.attr.get('width')) * RENDER_DPI['X']
        new_node['height'] = float(node.attr.get('height')) * RENDER_DPI['Y']
        # get the position of the CENTER of the node
        center_pos = [float(val)
                for val in node.attr.get('pos').split(',')]
        # apply dpi-conversion from 72 to 96
        center_pos[0] *= (RENDER_DPI['X'] / dpi)

        # translate y-coord from bottom-left to top-left corner
        center_pos[1] = (
                bb_height - center_pos[1]) * (RENDER_DPI['Y'] / dpi)
        new_node['pos'] = [center_pos[0] - (new_node['width'] / 2.0),
                           center_pos[1] - (new_node['height'] / 2.0)]
        nodes.append(new_node)
    return nodes


def update(scene):
    '''
        Parse the graph symbols and create a graphviz graph
        Used to update the edges in case user moves nodes.
    '''
    nodes = [{'name':node.name, 'pos':
        node.mapToScene(node.boundingRect().center()),
        'shape': type(node), 'width': node.boundingRect().width(),
        'height': node.boundingRect().height()}
        for node in scene.items() if isinstance(node,
                                               (Point, Diamond, Record))]
    graph = dotgraph.AGraph(
            strict=False, directed=True, splines='spline', start='rand')

    lookup = {Point: 'point', Record: 'record', Diamond: 'diamond'}
    for node in nodes:
        center_pos = node['pos']
        bb_height = scene.itemsBoundingRect().height()

        dpi = 72.0

        # Convert to graphviz coordinates / adapt DPI
        center_x = center_pos.x() * (dpi / RENDER_DPI['X'])
        center_y = (bb_height - center_pos.y()) * (dpi / RENDER_DPI['Y'])

        pos = unicode('{x},{y}'.format(x=int(center_x), y=int(center_y)))

        #print node['name'], node['height'], node['height'] / RENDER_DPI['Y']

        if node['shape'] in (Point, Diamond):
            graph.add_node(node['name'], pos=pos, shape=lookup[node['shape']],
                fixedsize='true', width=node['width'] / RENDER_DPI['X'],
                height=node['height'] / RENDER_DPI['Y'])
        else:
            graph.add_node(node['name'], pos=pos, shape=lookup[node['shape']])

    # Keep edges from the previous graph
    for edge in EDGES:
        graph.add_edge(edge, label=edge.attr.get('label') or '')

    #print graph.to_string()
    if nodes:
        #before = scene.itemsBoundingRect().center()
        render_statechart(scene, graph, keep_pos=True)
        #delta = scene.itemsBoundingRect().center() - before
        # graphviz translates the graph to pos (0, 0) -> move it back
        # to the exact graphical position where the user clicked
        #for item in scene.items():
        #    if isinstance(item, genericSymbols.Symbol):
        #        item.setPos(item.pos() - delta)


def render_statechart(scene, graph=None, keep_pos=False):
    ''' Render a graphviz/dot statechart on the QGraphicsScene '''
    # Statechart symbols lookup table
    lookup = {'point': Point, 'record': Record, 'diamond': Diamond}
    try:
        # Bonus: the tool can render any dot graph...
        graph = graph or dotgraph.AGraph('taste.dot')
    except IOError:
        LOG.info('No statechart to display....')
        raise
    graph.graph_attr.update(dpi='72.0')
    EDGES[:] = graph.edges()

    scene.clear()
    G_SYMBOLS.clear()

    # Compute all the coordinates (self-modifying function)
    # Force the fontsize of the nodes to be 12, as in OpenGEODE
    # use -n2 below to keep user-specified node coordinates
    graph.layout(prog='neato', args='-Nfontsize=12, -Gsplines=true -Gsep=1 '
            '-Gstart=random10 '
            '-Nstyle=rounded -Nshape=record -Elen=1.5 {kp}'
            .format(kp='-n1' if keep_pos else ''))
    # bb is not visible directly - extract it from the low level api:
    bounding_rect = [float(val) for val in
            dotgraph.graphviz.agget(graph.handle, 'bb').split(',')]
    dot_dpi = float(dotgraph.graphviz.agget(graph.handle, 'dpi'))
    # dot uses a 72 dpi value for converting its position coordinates
    # Get actual rendering DPI from Qt view
    for view in scene.views():
        RENDER_DPI['X'] = view.physicalDpiX()
        RENDER_DPI['Y'] = view.physicalDpiY()

    #fontname = graph.graph_attr.get('fontname')
    #fontsize = graph.graph_attr.get('fontsize')
    #print 'AFTER PROCESSING: ', graph.to_string()

    nodes = preprocess_nodes(graph, bounding_rect, dot_dpi)
    node_symbols = []
    for node in nodes:
        shape = node.get('shape')
        try:
            node_symbol = lookup[shape](node, graph)
        except KeyError:
            raise TypeError('Statechart - unsupported shape: ' + shape)
        G_SYMBOLS.add(node_symbol)
        node_symbols.append(node_symbol)
        scene.addItem(node_symbol)
    edges = preprocess_edges(graph, node_symbols, bounding_rect, dot_dpi)

    for edge in edges:
        Edge(edge, graph)


if __name__ == '__main__':
    render_statechart(None)