QGIS/python/plugins/processing/modeler/ModelerArrowItem.py

# -*- coding: utf-8 -*-

"""
***************************************************************************
    Portions of this code have been taken and adapted from PyQt
    examples, released under the following license terms

#############################################################################
#
# Copyright (C) 2010 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
# 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."
# $QT_END_LICENSE$
#
***************************************************************************
"""

import math
from PyQt4 import QtCore, QtGui
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.modeler.ModelerGraphicItem import ModelerGraphicItem


class ModelerArrowItem(QtGui.QGraphicsPathItem):

    def __init__(self, startItem, outputIndex, endItem, paramIndex,
                 parent=None, scene=None):
        super(ModelerArrowItem, self).__init__(parent, scene)
        self.arrowHead = QtGui.QPolygonF()
        self.paramIndex = paramIndex
        self.outputIndex = outputIndex
        self.myStartItem = startItem
        self.myEndItem = endItem
        self.setFlag(QtGui.QGraphicsItem.ItemIsSelectable, False)
        self.myColor = QtCore.Qt.gray
        self.setPen(QtGui.QPen(self.myColor, 1, QtCore.Qt.SolidLine,
                    QtCore.Qt.RoundCap, QtCore.Qt.RoundJoin))
        self.setZValue(0)

    def startItem(self):
        return self.myStartItem

    def endItem(self):
        return self.myEndItem

    def paint(self, painter, option, widget=None):
        startItem = self.myStartItem
        endItem = self.myEndItem
        myPen = self.pen()
        myPen.setColor(self.myColor)
        painter.setPen(myPen)
        painter.setBrush(self.myColor)

        controlPoints = []
        endPt = self.endItem().getLinkPointForParameter(self.paramIndex)
        startPt = self.startItem().getLinkPointForOutput(self.outputIndex)
        if isinstance(self.startItem().element, GeoAlgorithm):
            if self.startItem().element.outputs:
                controlPoints.append(startItem.pos() + startPt)
                controlPoints.append(startItem.pos() + startPt
                        + QtCore.QPointF(ModelerGraphicItem.BOX_WIDTH / 2, 0))
                controlPoints.append(endItem.pos() + endPt
                        - QtCore.QPointF(ModelerGraphicItem.BOX_WIDTH / 2, 0))
                controlPoints.append(endItem.pos() + endPt)
                pt = QtCore.QPointF(startItem.pos() + startPt
                        + QtCore.QPointF(-3, -3))
                painter.drawEllipse(pt.x(), pt.y(), 6, 6)
                pt = QtCore.QPointF(endItem.pos() + endPt +
                        QtCore.QPointF(-3, -3))
                painter.drawEllipse(pt.x(), pt.y(), 6, 6)
            else:
                # Case where there is a dependency on an algorithm not
                # on an output
                controlPoints.append(startItem.pos() + startPt)
                controlPoints.append(startItem.pos() + startPt
                        + QtCore.QPointF(ModelerGraphicItem.BOX_WIDTH / 2, 0))
                controlPoints.append(endItem.pos() + endPt
                        - QtCore.QPointF(ModelerGraphicItem.BOX_WIDTH / 2, 0))
                controlPoints.append(endItem.pos() + endPt)
        else:
            controlPoints.append(startItem.pos())
            controlPoints.append(startItem.pos()
                    + QtCore.QPointF(ModelerGraphicItem.BOX_WIDTH / 2, 0))
            controlPoints.append(endItem.pos() + endPt
                    - QtCore.QPointF(ModelerGraphicItem.BOX_WIDTH / 2, 0))
            controlPoints.append(endItem.pos() + endPt)
            pt = QtCore.QPointF(endItem.pos() + endPt + QtCore.QPointF(-3, -3))
            painter.drawEllipse(pt.x(), pt.y(), 6, 6)

        path = QtGui.QPainterPath()
        path.moveTo(controlPoints[0])
        path.cubicTo(*controlPoints[1:])
        painter.strokePath(path, painter.pen())
        self.setPath(path)