TDTangentialMeasure.FCMacro

"""
This Macro is intended to be used in the TechDraw Workbench,
to find the tangential points on two circles, which are parallel to a given reference.

Select three edges: two circles and a "axis" line.

"""
__Name__ = 'TDTangentialMeasure'
__Comment__ = 'Create a tangential measure on two arcs by aligning to an axis'
__Author__ = 'Sebastian Bachmann'
__Version__ = '0.9'
__Date__ = '2020-05-07'
__License__ = 'MIT'
__Web__ = 'https://github.com/reox/FreeCAD_Macros'
__Wiki__ = ''
__Icon__ = 'icons/TDTangentialMeasure.svg'
__Help__ = 'Select two arcs where the tangential measure shall be applied ' \
           'and an additional straight line which will be the axis. ' \
           'The macro will create four cosmetic vertices: two at the arcs ' \
           'and two at the opposing sites in order to apply a distance measure.'
__Status__ = 'Beta'
__Requires__ = '>=0.19.20943; py3 only'
__Communication__ = 'https://github.com/reox/FreeCAD_Macros/issues'

# Copyright (c) 2020, Sebastian Bachmann <hello@reox.at>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in
# the Software without restriction, including without limitation the rights to
# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

import numpy as np
from PySide.QtGui import QMessageBox
from PySide import QtCore


def msg(title, message):
    diag = QMessageBox(QMessageBox.Warning, title, message)
    diag.setWindowModality(QtCore.Qt.ApplicationModal)
    diag.exec_()


def find_tangential():
    """
    Finds the intersection point of two edges
    And creates a cosmetic vertex there
    """
    # Get the current view:
    cur_view = Gui.Selection.getSelectionEx()[0].Object


    if not cur_view.isDerivedFrom("TechDraw::DrawViewPart"):
        msg("Wrong Selection", "Must select Edges of DrawViewPart!")
        return

    # Get the names of the selected edges:
    elem = Gui.Selection.getSelectionEx()[0].SubElementNames

    if not all(map(lambda x: x.startswith('Edge'), elem)) or len(elem) != 3:
        msg("Wrong Selection", "You have not selected three edges!")
        return

    try:
        indices = map(lambda x: int(x.replace('Edge', '')), elem)
    except ValueError as e:
        msg("Something is wrong", "Can not parse Edge indices: {}".format(e))
        return

    # Edge -> Curve (Circle) -> Location + Radius
    #      -> Curve (Line)   -> Direction

    items = list(map(lambda a: cur_view.getEdgeByIndex(a), indices))

    points = []
    directions = []
    radii = []
    dir = None

    for item in items:
        if item.Curve.TypeId == 'Part::GeomCircle':
            v1, v2 = item.Vertexes
            # Calculate the "direction vector" of the circle
            p = (item.Curve.Location - v1.Point) + (item.Curve.Location - v2.Point)
            p.normalize()
            points.append(item.Curve.Location)
            directions.append(p)
            radii.append(item.Curve.Radius)
        elif item.Curve.TypeId == 'Part::GeomLine':
            dir = item.Curve.Direction
        else:
            print("Where do I belong?", item.Curve.TypeId)

    if dir is None or len(points) != 2:
        msg("Wrong Selection", "Please select two arcs and a straight line!")
        return

    p1, p2 = points
    d1, d2 = directions
    r1, r2 = radii

    def dir_sign(v1, v2):
        """Calculate the directional sign of two vectors"""
        a = v1.getAngle(v2)
        # TODO: is this correct?! I thought that we would return 1 here and -1 otherwise...
        #       Probably a problem because of the two coordinate system which are used in TD
        if a < np.pi / 2.0 or a >= (3.0/2.0) * np.pi:
            return -1
        return 1

    # Can be enabled to create a vertex at the arc's center
    #cur_view.makeCosmeticVertex(p1)
    #cur_view.makeCosmeticVertex(p2)

    # Tangential points in direction of axis
    vert1 = p1 + dir_sign(dir, d1) * dir * r1
    vert2 = p2 + dir_sign(dir, d2) * dir * r2
    cur_view.makeCosmeticVertex(vert1)
    cur_view.makeCosmeticVertex(vert2)

    # We can "fake" the measurement by creating the point which can be used to measure the distance
    distance = dir.dot(vert1 - vert2)
    vert3 = vert2 + (dir * distance)
    cur_view.makeCosmeticVertex(vert3)

    # Also create the other vertex, so we have an option to choose
    vert4 = vert1 - (dir * distance)
    cur_view.makeCosmeticVertex(vert4)


    # Recompute
    App.activeDocument().recompute(None,True,True)


if __name__ == "__main__":
    find_tangential()