#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
## "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 Nokia Corporation and its Subsidiary(-ies) 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
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## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
## $QT_END_LICENSE$
##
#############################################################################
import math
from PyQt5.QtCore import (qAbs, QLineF, QPointF, qrand, QRectF, QSizeF, qsrand,
Qt, QTime)
from PyQt5.QtGui import (QBrush, QColor, QLinearGradient, QPainter,
QPainterPath, QPen, QPolygonF, QRadialGradient)
from PyQt5.QtWidgets import (QApplication, QGraphicsItem, QGraphicsScene,
QGraphicsView, QStyle)
class Edge(QGraphicsItem):
Pi = math.pi
TwoPi = 2.0 * Pi
Type = QGraphicsItem.UserType + 2
def __init__(self, sourceNode, destNode):
super(Edge, self).__init__()
self.arrowSize = 10.0
self.sourcePoint = QPointF()
self.destPoint = QPointF()
self.setAcceptedMouseButtons(Qt.NoButton)
self.source = sourceNode
self.dest = destNode
self.source.addEdge(self)
self.dest.addEdge(self)
self.adjust()
def type(self):
return Edge.Type
def sourceNode(self):
return self.source
def setSourceNode(self, node):
self.source = node
self.adjust()
def destNode(self):
return self.dest
def setDestNode(self, node):
self.dest = node
self.adjust()
def adjust(self):
if not self.source or not self.dest:
return
line = QLineF(self.mapFromItem(self.source, 0, 0),
self.mapFromItem(self.dest, 0, 0))
length = line.length()
self.prepareGeometryChange()
if length > 20.0:
edgeOffset = QPointF((line.dx() * 10) / length,
(line.dy() * 10) / length)
self.sourcePoint = line.p1() + edgeOffset
self.destPoint = line.p2() - edgeOffset
else:
self.sourcePoint = line.p1()
self.destPoint = line.p1()
def boundingRect(self):
if not self.source or not self.dest:
return QRectF()
penWidth = 1.0
extra = (penWidth + self.arrowSize) / 2.0
return QRectF(self.sourcePoint,
QSizeF(self.destPoint.x() - self.sourcePoint.x(),
self.destPoint.y() - self.sourcePoint.y())).normalized().adjusted(-extra, -extra, extra, extra)
def paint(self, painter, option, widget):
if not self.source or not self.dest:
return
# Draw the line itself.
line = QLineF(self.sourcePoint, self.destPoint)
if line.length() == 0.0:
return
painter.setPen(QPen(Qt.black, 1, Qt.SolidLine, Qt.RoundCap,
Qt.RoundJoin))
painter.drawLine(line)
# Draw the arrows if there's enough room.
angle = math.acos(line.dx() / line.length())
if line.dy() >= 0:
angle = Edge.TwoPi - angle
sourceArrowP1 = self.sourcePoint + QPointF(math.sin(angle + Edge.Pi / 3) * self.arrowSize,
math.cos(angle + Edge.Pi / 3) * self.arrowSize)
sourceArrowP2 = self.sourcePoint + QPointF(math.sin(angle + Edge.Pi - Edge.Pi / 3) * self.arrowSize,
math.cos(angle + Edge.Pi - Edge.Pi / 3) * self.arrowSize);
destArrowP1 = self.destPoint + QPointF(math.sin(angle - Edge.Pi / 3) * self.arrowSize,
math.cos(angle - Edge.Pi / 3) * self.arrowSize)
destArrowP2 = self.destPoint + QPointF(math.sin(angle - Edge.Pi + Edge.Pi / 3) * self.arrowSize,
math.cos(angle - Edge.Pi + Edge.Pi / 3) * self.arrowSize)
painter.setBrush(Qt.black)
painter.drawPolygon(QPolygonF([line.p1(), sourceArrowP1, sourceArrowP2]))
painter.drawPolygon(QPolygonF([line.p2(), destArrowP1, destArrowP2]))
class Node(QGraphicsItem):
Type = QGraphicsItem.UserType + 1
def __init__(self, graphWidget):
super(Node, self).__init__()
self.graph = graphWidget
self.edgeList = []
self.newPos = QPointF()
self.setFlag(QGraphicsItem.ItemIsMovable)
self.setFlag(QGraphicsItem.ItemSendsGeometryChanges)
self.setCacheMode(QGraphicsItem.DeviceCoordinateCache)
self.setZValue(1)
def type(self):
return Node.Type
def addEdge(self, edge):
self.edgeList.append(edge)
edge.adjust()
def edges(self):
return self.edgeList
def calculateForces(self):
if not self.scene() or self.scene().mouseGrabberItem() is self:
self.newPos = self.pos()
return
# Sum up all forces pushing this item away.
xvel = 0.0
yvel = 0.0
for item in self.scene().items():
if not isinstance(item, Node):
continue
line = QLineF(self.mapFromItem(item, 0, 0), QPointF(0, 0))
dx = line.dx()
dy = line.dy()
l = 2.0 * (dx * dx + dy * dy)
if l > 0:
xvel += (dx * 150.0) / l
yvel += (dy * 150.0) / l
# Now subtract all forces pulling items together.
weight = (len(self.edgeList) + 1) * 10.0
for edge in self.edgeList:
if edge.sourceNode() is self:
pos = self.mapFromItem(edge.destNode(), 0, 0)
else:
pos = self.mapFromItem(edge.sourceNode(), 0, 0)
xvel += pos.x() / weight
yvel += pos.y() / weight
if qAbs(xvel) < 0.1 and qAbs(yvel) < 0.1:
xvel = yvel = 0.0
sceneRect = self.scene().sceneRect()
self.newPos = self.pos() + QPointF(xvel, yvel)
self.newPos.setX(min(max(self.newPos.x(), sceneRect.left() + 10), sceneRect.right() - 10))
self.newPos.setY(min(max(self.newPos.y(), sceneRect.top() + 10), sceneRect.bottom() - 10))
def advance(self):
if self.newPos == self.pos():
return False
self.setPos(self.newPos)
return True
def boundingRect(self):
adjust = 2.0
return QRectF(-10 - adjust, -10 - adjust, 23 + adjust, 23 + adjust)
def shape(self):
path = QPainterPath()
path.addEllipse(-10, -10, 20, 20)
return path
def paint(self, painter, option, widget):
painter.setPen(Qt.NoPen)
painter.setBrush(Qt.darkGray)
painter.drawEllipse(-7, -7, 20, 20)
gradient = QRadialGradient(-3, -3, 10)
if option.state & QStyle.State_Sunken:
gradient.setCenter(3, 3)
gradient.setFocalPoint(3, 3)
gradient.setColorAt(1, QColor(Qt.yellow).lighter(120))
gradient.setColorAt(0, QColor(Qt.darkYellow).lighter(120))
else:
gradient.setColorAt(0, Qt.yellow)
gradient.setColorAt(1, Qt.darkYellow)
painter.setBrush(QBrush(gradient))
painter.setPen(QPen(Qt.black, 0))
painter.drawEllipse(-10, -10, 20, 20)
def itemChange(self, change, value):
if change == QGraphicsItem.ItemPositionHasChanged:
for edge in self.edgeList:
edge.adjust()
self.graph.itemMoved()
return super(Node, self).itemChange(change, value)
def mousePressEvent(self, event):
self.update()
super(Node, self).mousePressEvent(event)
def mouseReleaseEvent(self, event):
self.update()
super(Node, self).mouseReleaseEvent(event)
class GraphWidget(QGraphicsView):
def __init__(self):
super(GraphWidget, self).__init__()
self.timerId = 0
scene = QGraphicsScene(self)
scene.setItemIndexMethod(QGraphicsScene.NoIndex)
scene.setSceneRect(-200, -200, 400, 400)
self.setScene(scene)
self.setCacheMode(QGraphicsView.CacheBackground)
self.setViewportUpdateMode(QGraphicsView.BoundingRectViewportUpdate)
self.setRenderHint(QPainter.Antialiasing)
self.setTransformationAnchor(QGraphicsView.AnchorUnderMouse)
self.setResizeAnchor(QGraphicsView.AnchorViewCenter)
node1 = Node(self)
node2 = Node(self)
node3 = Node(self)
node4 = Node(self)
self.centerNode = Node(self)
node6 = Node(self)
node7 = Node(self)
node8 = Node(self)
node9 = Node(self)
scene.addItem(node1)
scene.addItem(node2)
scene.addItem(node3)
scene.addItem(node4)
scene.addItem(self.centerNode)
scene.addItem(node6)
scene.addItem(node7)
scene.addItem(node8)
scene.addItem(node9)
scene.addItem(Edge(node1, node2))
scene.addItem(Edge(node2, node3))
scene.addItem(Edge(node2, self.centerNode))
scene.addItem(Edge(node3, node6))
scene.addItem(Edge(node4, node1))
scene.addItem(Edge(node4, self.centerNode))
scene.addItem(Edge(self.centerNode, node6))
scene.addItem(Edge(self.centerNode, node8))
scene.addItem(Edge(node6, node9))
scene.addItem(Edge(node7, node4))
scene.addItem(Edge(node8, node7))
scene.addItem(Edge(node9, node8))
node1.setPos(-50, -50)
node2.setPos(0, -50)
node3.setPos(50, -50)
node4.setPos(-50, 0)
self.centerNode.setPos(0, 0)
node6.setPos(50, 0)
node7.setPos(-50, 50)
node8.setPos(0, 50)
node9.setPos(50, 50)
self.scale(0.8, 0.8)
self.setMinimumSize(400, 400)
self.setWindowTitle("Elastic Nodes")
def itemMoved(self):
if not self.timerId:
self.timerId = self.startTimer(1000 / 25)
def keyPressEvent(self, event):
key = event.key()
if key == Qt.Key_Up:
self.centerNode.moveBy(0, -20)
elif key == Qt.Key_Down:
self.centerNode.moveBy(0, 20)
elif key == Qt.Key_Left:
self.centerNode.moveBy(-20, 0)
elif key == Qt.Key_Right:
self.centerNode.moveBy(20, 0)
elif key == Qt.Key_Plus:
self.scaleView(1.2)
elif key == Qt.Key_Minus:
self.scaleView(1 / 1.2)
elif key == Qt.Key_Space or key == Qt.Key_Enter:
for item in self.scene().items():
if isinstance(item, Node):
item.setPos(-150 + qrand() % 300, -150 + qrand() % 300)
else:
super(GraphWidget, self).keyPressEvent(event)
def timerEvent(self, event):
nodes = [item for item in self.scene().items() if isinstance(item, Node)]
for node in nodes:
node.calculateForces()
itemsMoved = False
for node in nodes:
if node.advance():
itemsMoved = True
if not itemsMoved:
self.killTimer(self.timerId)
self.timerId = 0
def wheelEvent(self, event):
self.scaleView(math.pow(2.0, -event.angleDelta().y() / 240.0))
def drawBackground(self, painter, rect):
# Shadow.
sceneRect = self.sceneRect()
rightShadow = QRectF(sceneRect.right(), sceneRect.top() + 5, 5,
sceneRect.height())
bottomShadow = QRectF(sceneRect.left() + 5, sceneRect.bottom(),
sceneRect.width(), 5)
if rightShadow.intersects(rect) or rightShadow.contains(rect):
painter.fillRect(rightShadow, Qt.darkGray)
if bottomShadow.intersects(rect) or bottomShadow.contains(rect):
painter.fillRect(bottomShadow, Qt.darkGray)
# Fill.
gradient = QLinearGradient(sceneRect.topLeft(), sceneRect.bottomRight())
gradient.setColorAt(0, Qt.white)
gradient.setColorAt(1, Qt.lightGray)
painter.fillRect(rect.intersected(sceneRect), QBrush(gradient))
painter.setBrush(Qt.NoBrush)
painter.drawRect(sceneRect)
# Text.
textRect = QRectF(sceneRect.left() + 4, sceneRect.top() + 4,
sceneRect.width() - 4, sceneRect.height() - 4)
message = "Click and drag the nodes around, and zoom with the " \
"mouse wheel or the '+' and '-' keys"
font = painter.font()
font.setBold(True)
font.setPointSize(14)
painter.setFont(font)
painter.setPen(Qt.lightGray)
painter.drawText(textRect.translated(2, 2), message)
painter.setPen(Qt.black)
painter.drawText(textRect, message)
def scaleView(self, scaleFactor):
factor = self.matrix().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width()
if factor < 0.07 or factor > 100:
return
self.scale(scaleFactor, scaleFactor)
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
qsrand(QTime(0,0,0).secsTo(QTime.currentTime()))
widget = GraphWidget()
widget.show()
sys.exit(app.exec_())
