#!/usr/bin/env python # coding=utf-8 ''' Copyright (C) 2008 Aaron Spike, [email protected] Copyright (C) 2013 Sebastian WÃ¼st, [email protected] Copyright (C) 2016 Alexander Pruss This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ''' # standard libraries import math class OffsetProcessor: def __init__(self, toolOffset=1., overcut=0.2, tolerance=0.01): self.toolOffset = toolOffset self.overcut = overcut self.tolerance = tolerance self.PI = math.pi self.TWO_PI = 2 * math.pi if self.toolOffset > 0.0: self.toolOffsetFlat = self.tolerance / self.toolOffset * 4.5 # scale flatness to offset else: self.toolOffsetFlat = 0.0 @staticmethod def changeLength(x1, y1, x2, y2, offset): # change length of line d = OffsetProcessor.getLength(x1, y1, x2, y2) if offset < 0: offset = max( -d, offset) x = x2 + (x2 - x1) / d * offset y = y2 + (y2 - y1) / d * offset return [x, y] @staticmethod def getLength(ax,ay,bx,by): return math.sqrt((ax-bx)**2+(ay-by)**2) def processOffset(self, cmd, posX, posY): # calculate offset correction (or dont) if self.toolOffset == 0.0: self.storePoint(cmd, posX, posY) else: # insert data into cache self.vData.pop(0) self.vData.insert(3, [cmd, posX, posY]) # decide if enough data is availabe if self.vData[2][1] != -1.0: if self.vData[1][1] == -1.0: self.storePoint(self.vData[2][0], self.vData[2][1], self.vData[2][2]) else: # perform tool offset correction (It's a *tad* complicated, if you want to understand it draw the data as lines on paper) if self.vData[2][0] == 'PD': # If the 3rd entry in the cache is a pen down command make the line longer by the tool offset pointThree = OffsetProcessor.changeLength(self.vData[1][1], self.vData[1][2], self.vData[2][1], self.vData[2][2], self.toolOffset) self.storePoint('PD', pointThree[0], pointThree[1]) elif self.vData[0][1] != -1.0: # Elif the 1st entry in the cache is filled with data and the 3rd entry is a pen up command shift # the 3rd entry by the current tool offset position according to the 2nd command pointThree = OffsetProcessor.changeLength(self.vData[0][1], self.vData[0][2], self.vData[1][1], self.vData[1][2], self.toolOffset) pointThree[0] = self.vData[2][1] - (self.vData[1][1] - pointThree[0]) pointThree[1] = self.vData[2][2] - (self.vData[1][2] - pointThree[1]) self.storePoint('PU', pointThree[0], pointThree[1]) else: # Else just write the 3rd entry pointThree = [self.vData[2][1], self.vData[2][2]] self.storePoint('PU', pointThree[0], pointThree[1]) if self.vData[3][0] == 'PD': # If the 4th entry in the cache is a pen down command guide tool to next line with a circle between the prolonged 3rd and 4th entry if OffsetProcessor.getLength(self.vData[2][1], self.vData[2][2], self.vData[3][1], self.vData[3][2]) >= self.toolOffset: pointFour = OffsetProcessor.changeLength(self.vData[3][1], self.vData[3][2], self.vData[2][1], self.vData[2][2], - self.toolOffset) else: pointFour = OffsetProcessor.changeLength(self.vData[2][1], self.vData[2][2], self.vData[3][1], self.vData[3][2], (self.toolOffset - OffsetProcessor.getLength(self.vData[2][1], self.vData[2][2], self.vData[3][1], self.vData[3][2]))) # get angle start and angle vector angleStart = math.atan2(pointThree[1] - self.vData[2][2], pointThree[0] - self.vData[2][1]) angleVector = math.atan2(pointFour[1] - self.vData[2][2], pointFour[0] - self.vData[2][1]) - angleStart # switch direction when arc is bigger than 180Â° if angleVector > self.PI: angleVector -= self.TWO_PI elif angleVector < - self.PI: angleVector += self.TWO_PI # draw arc if angleVector >= 0: angle = angleStart + self.toolOffsetFlat while angle < angleStart + angleVector: self.storePoint('PD', self.vData[2][1] + math.cos(angle) * self.toolOffset, self.vData[2][2] + math.sin(angle) * self.toolOffset) angle += self.toolOffsetFlat else: angle = angleStart - self.toolOffsetFlat while angle > angleStart + angleVector: self.storePoint('PD', self.vData[2][1] + math.cos(angle) * self.toolOffset, self.vData[2][2] + math.sin(angle) * self.toolOffset) angle -= self.toolOffsetFlat self.storePoint('PD', pointFour[0], pointFour[1]) def storePoint(self, command, x, y): # skip when no change in movement if self.lastPoint[0] == command and self.lastPoint[1] == x and self.lastPoint[2] == y: return if command == 'PD': self.curPath.append((x,y)) elif command == 'PU': if len(self.curPath) > 1: self.paths.append(self.curPath) self.curPath = [] self.curPath.append((x,y)) self.lastPoint = [command, x, y] def processPath(self, path): self.vData = [['', -1.0, -1.0], ['', -1.0, -1.0], ['', -1.0, -1.0], ['', -1.0, -1.0]] self.paths = [] self.curPath = [] self.lastPoint = [0, 0, 0] self.processOffset('PU', 0, 0) oldPosX = float("inf") oldPosY = float("inf") for singlePath in path: cmd = 'PU' for singlePathPoint in singlePath: posX, posY = singlePathPoint # check if point is repeating, if so, ignore if OffsetProcessor.getLength(oldPosX,oldPosY,posX,posY) >= self.tolerance: self.processOffset(cmd, posX, posY) cmd = 'PD' oldPosX = posX oldPosY = posY # perform overcut if self.overcut > 0.0: # check if last and first points are the same, otherwise the path is not closed and no overcut can be performed if OffsetProcessor.getLength(oldPosX,oldPosY,singlePath[0][0],singlePath[0][1]) <= self.tolerance: overcutLength = 0 for singlePathPoint in singlePath: posX, posY = singlePathPoint # check if point is repeating, if so, ignore distance = OffsetProcessor.getLength(oldPosX,oldPosY, posX,posY) if distance >= self.tolerance: overcutLength += distance if overcutLength >= self.overcut: newLength = OffsetProcessor.changeLength(oldPosX, oldPosY, posX, posY, - (overcutLength - self.overcut)) self.processOffset(cmd, newLength[0], newLength[1]) break else: self.processOffset(cmd, posX, posY) oldPosX = posX oldPosY = posY self.processOffset('PU', 0, 0) if len(self.curPath) > 1: self.paths.append(self.curPath) return self.paths if __name__ == '__main__': paths = [[(0,0),(20,0),(20,20),(0,20),(0,0)], [(0,0),(20,0),(20,20),(0,20),(0,0)]] op = OffsetProcessor() print(op.processPath(paths))