path: root/share/extensions/hpgl_encoder.py

# coding=utf-8
#
# Copyright (C) 2008 Aaron Spike, aaron@ekips.org
#
# 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
"""
Base class for HGPL Encoding
"""

import re
import math

import inkex
from inkex.transforms import Transform, DirectedLineSegment, Vector2d
from inkex.bezier import cspsubdiv


class NoPathError(ValueError):
    """Raise that paths not selected"""


# Find the pen number in the layer number
FIND_PEN = re.compile(r"\s*pen\s*(\d+)\s*", re.IGNORECASE)
# Find the pen speed in the layer number
FIND_SPEED = re.compile(r"\s*speed\s*(\d+)\s*", re.IGNORECASE)
# Find pen force in the layer name
FIND_FORCE = re.compile(r"\s*force\s*(\d+)\s*", re.IGNORECASE)


class hpglEncoder(object):
    """HPGL Encoder, used by others"""

    def __init__(self, effect):
        """options:
        "resolutionX":float
        "resolutionY":float
        "pen":int
        "force:int
        "speed:int
        "orientation":string // "0", "90", "-90", "180"
        "mirrorX":bool
        "mirrorY":bool
        "center":bool
        "flat":float
        "overcut":float
        "toolOffset":float
        "precut":bool
        "autoAlign":bool
        """
        self.options = effect.options
        self.doc = effect.svg
        self.docWidth = effect.svg.viewbox_width
        self.docHeight = effect.svg.viewbox_height
        self.hpgl = ""
        self.divergenceX = "False"
        self.divergenceY = "False"
        self.sizeX = "False"
        self.sizeY = "False"
        self.dryRun = True
        self.lastPoint = [0, 0, 0]
        self.lastPen = -1
        self.lastSpeed = -1
        self.lastForce = -1
        self.offsetX = 0
        self.offsetY = 0
        # dots per inch to dots per user unit:

        self.scaleX = self.options.resolutionX / effect.svg.viewport_to_unit("1.0in")
        self.scaleY = self.options.resolutionY / effect.svg.viewport_to_unit("1.0in")
        scaleXY = (self.scaleX + self.scaleY) / 2

        # mm to dots (plotter coordinate system):
        self.overcut = (
            effect.svg.viewport_to_unit(str(self.options.overcut) + "mm") * scaleXY
        )
        self.toolOffset = (
            effect.svg.viewport_to_unit(str(self.options.toolOffset) + "mm") * scaleXY
        )

        # scale flatness to resolution:
        self.flat = self.options.flat / (
            1016 / ((self.options.resolutionX + self.options.resolutionY) / 2)
        )
        if self.toolOffset > 0.0:
            self.toolOffsetFlat = (
                self.flat / self.toolOffset * 4.5
            )  # scale flatness to offset
        else:
            self.toolOffsetFlat = 0.0
        self.mirrorX = -1.0 if self.options.mirrorX else 1.0
        self.mirrorY = 1.0 if self.options.mirrorY else -1.0
        # process viewBox attribute to correct page scaling
        self.viewBoxTransformX = 1
        self.viewBoxTransformY = 1
        viewBox = effect.svg.get_viewbox()
        if viewBox and viewBox[2] and viewBox[3]:
            self.viewBoxTransformX = self.docWidth / effect.svg.viewport_to_unit(
                effect.svg.add_unit(viewBox[2])
            )
            self.viewBoxTransformY = self.docHeight / effect.svg.viewport_to_unit(
                effect.svg.add_unit(viewBox[3])
            )

    def getHpgl(self):
        """Return the HPGL instructions"""
        # dryRun to find edges
        transform = Transform(
            [
                [self.mirrorX * self.scaleX * self.viewBoxTransformX, 0.0, 0.0],
                [0.0, self.mirrorY * self.scaleY * self.viewBoxTransformY, 0.0],
            ]
        )
        transform.add_rotate(int(self.options.orientation))

        self.vData = [
            ["", "False", 0],
            ["", "False", 0],
            ["", "False", 0],
            ["", "False", 0],
        ]
        self.process_group(self.doc, transform)
        if (
            self.divergenceX == "False"
            or self.divergenceY == "False"
            or self.sizeX == "False"
            or self.sizeY == "False"
        ):
            raise NoPathError("No paths found")
        # live run
        self.dryRun = False
        # move drawing according to various modifiers
        if self.options.autoAlign:
            if self.options.center:
                self.offsetX -= (self.sizeX - self.divergenceX) / 2
                self.offsetY -= (self.sizeY - self.divergenceY) / 2
        else:
            self.divergenceX = 0.0
            self.divergenceY = 0.0
            if self.options.center:
                if self.options.orientation == "0":
                    self.offsetX -= (self.docWidth * self.scaleX) / 2
                    self.offsetY += (self.docHeight * self.scaleY) / 2
                if self.options.orientation == "90":
                    self.offsetY += (self.docWidth * self.scaleX) / 2
                    self.offsetX += (self.docHeight * self.scaleY) / 2
                if self.options.orientation == "180":
                    self.offsetX += (self.docWidth * self.scaleX) / 2
                    self.offsetY -= (self.docHeight * self.scaleY) / 2
                if self.options.orientation == "270":
                    self.offsetY -= (self.docWidth * self.scaleX) / 2
                    self.offsetX -= (self.docHeight * self.scaleY) / 2
            else:
                if self.options.orientation == "0":
                    self.offsetY += self.docHeight * self.scaleY
                if self.options.orientation == "90":
                    self.offsetY += self.docWidth * self.scaleX
                    self.offsetX += self.docHeight * self.scaleY
                if self.options.orientation == "180":
                    self.offsetX += self.docWidth * self.scaleX
        if not self.options.center and self.toolOffset > 0.0:
            self.offsetX += self.toolOffset
            self.offsetY += self.toolOffset

        # initialize transformation matrix and cache
        transform = Transform(
            [
                [
                    self.mirrorX * self.scaleX * self.viewBoxTransformX,
                    0.0,
                    -float(self.divergenceX) + self.offsetX,
                ],
                [
                    0.0,
                    self.mirrorY * self.scaleY * self.viewBoxTransformY,
                    -float(self.divergenceY) + self.offsetY,
                ],
            ]
        )
        transform.add_rotate(int(self.options.orientation))
        self.vData = [
            ["", "False", 0],
            ["", "False", 0],
            ["", "False", 0],
            ["", "False", 0],
        ]
        # add move to zero point and precut
        if self.toolOffset > 0.0 and self.options.precut:
            if self.options.center:
                # position precut outside of drawing plus one time the tooloffset
                if self.offsetX >= 0.0:
                    precutX = self.offsetX + self.toolOffset
                else:
                    precutX = self.offsetX - self.toolOffset
                if self.offsetY >= 0.0:
                    precutY = self.offsetY + self.toolOffset
                else:
                    precutY = self.offsetY - self.toolOffset
                self.processOffset(
                    "PU",
                    Vector2d(precutX, precutY),
                    self.options.pen,
                    self.options.speed,
                    self.options.force,
                )
                self.processOffset(
                    "PD",
                    Vector2d(precutX, precutY + self.toolOffset * 8),
                    self.options.pen,
                    self.options.speed,
                    self.options.force,
                )
            else:
                self.processOffset(
                    "PU",
                    Vector2d(0, 0),
                    self.options.pen,
                    self.options.speed,
                    self.options.force,
                )
                self.processOffset(
                    "PD",
                    Vector2d(0, self.toolOffset * 8),
                    self.options.pen,
                    self.options.speed,
                    self.options.force,
                )
        # start conversion
        self.process_group(self.doc, transform)
        # shift an empty node in in order to process last node in cache
        if self.toolOffset > 0.0 and not self.dryRun:
            self.processOffset("PU", Vector2d(0, 0), 0, 0, 0)
        return self.hpgl

    def process_group(self, group, transform):
        """flatten layers and groups to avoid recursion"""
        for child in group:
            if not isinstance(child, inkex.ShapeElement):
                continue
            if child.is_visible():
                if isinstance(child, inkex.Group):
                    self.process_group(child, transform)
                elif isinstance(child, inkex.PathElement):
                    self.process_path(child, transform)
                else:
                    # This only works for shape elements (not text yet!)
                    new_elem = child.replace_with(child.to_path_element())
                    # Element is given composed transform b/c it's not added back to doc
                    new_elem.transform = child.composed_transform()
                    self.process_path(new_elem, transform)

    def get_pen_number(self, node):
        """Get pen number for node label (usually group)"""
        for parent in [node] + list(node.ancestors()):
            match = FIND_PEN.search(parent.label or "")
            if match:
                return int(match.group(1))
        return int(self.options.pen)

    def get_pen_speed(self, node):
        """Get pen speed for node label (usually group)"""
        for parent in [node] + list(node.ancestors()):
            match = FIND_SPEED.search(parent.label or "")
            if match:
                return int(match.group(1))
        return int(self.options.speed)

    def get_pen_force(self, node):
        """Get pen force for node label (usually group)"""
        for parent in [node] + list(node.ancestors()):
            match = FIND_FORCE.search(parent.label or "")
            if match:
                return int(match.group(1))
        return int(self.options.force)

    def process_path(self, node, transform):
        """Process the given element into a plotter path"""
        pen = self.get_pen_number(node)
        speed = self.get_pen_speed(node)
        force = self.get_pen_force(node)

        path = (
            node.path.to_absolute()
            .transform(node.composed_transform())
            .transform(transform)
            .to_superpath()
        )
        if path:
            cspsubdiv(path, self.flat)
            # path to HPGL commands
            oldPosX = 0.0
            oldPosY = 0.0
            for singlePath in path:
                cmd = "PU"
                for singlePathPoint in singlePath:
                    posX, posY = singlePathPoint[1]
                    # check if point is repeating, if so, ignore
                    if int(round(posX)) != int(round(oldPosX)) or int(
                        round(posY)
                    ) != int(round(oldPosY)):
                        self.processOffset(cmd, Vector2d(posX, posY), pen, speed, force)
                        cmd = "PD"
                        oldPosX = posX
                        oldPosY = posY
                # perform overcut
                if self.overcut > 0.0 and not self.dryRun:
                    # check if last and first points are the same, otherwise the path
                    # is not closed and no overcut can be performed
                    if int(round(oldPosX)) == int(round(singlePath[0][1][0])) and int(
                        round(oldPosY)
                    ) == int(round(singlePath[0][1][1])):
                        overcutLength = 0
                        for singlePathPoint in singlePath:
                            posX, posY = singlePathPoint[1]
                            # check if point is repeating, if so, ignore
                            if int(round(posX)) != int(round(oldPosX)) or int(
                                round(posY)
                            ) != int(round(oldPosY)):
                                overcutLength += (
                                    Vector2d(posX, posY) - (oldPosX, oldPosY)
                                ).length
                                if overcutLength >= self.overcut:
                                    newEndPoint = self.changeLength(
                                        Vector2d(oldPosX, oldPosY),
                                        Vector2d(posX, posY),
                                        -(overcutLength - self.overcut),
                                    )
                                    self.processOffset(
                                        cmd, newEndPoint, pen, speed, force
                                    )
                                    break
                                self.processOffset(
                                    cmd, Vector2d(posX, posY), pen, speed, force
                                )
                                oldPosX = posX
                                oldPosY = posY

    def changeLength(self, p1, p2, offset):
        """change length of line"""
        if p1.x == p2.x and p1.y == p2.y:  # abort if points are the same
            return p1
        return Vector2d(DirectedLineSegment(p2, p1).point_at_length(-offset))

    def processOffset(self, cmd, point, pen, speed, force):
        """Calculate offset correction"""
        if self.toolOffset == 0.0 or self.dryRun:
            self.storePoint(cmd, point, pen, speed, force)
        else:
            # insert data into cache
            self.vData.pop(0)
            self.vData.insert(3, [cmd, point, pen, speed, force])
            # decide if enough data is available
            if self.vData[2][1] != "False":
                if self.vData[1][1] == "False":
                    self.storePoint(
                        self.vData[2][0],
                        self.vData[2][1],
                        self.vData[2][2],
                        self.vData[2][3],
                        self.vData[2][4],
                    )
                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 = self.changeLength(
                            self.vData[1][1], self.vData[2][1], self.toolOffset
                        )
                        self.storePoint(
                            "PD",
                            pointThree,
                            self.vData[2][2],
                            self.vData[2][3],
                            self.vData[2][4],
                        )
                    elif self.vData[0][1] != "False":
                        # 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 = self.changeLength(
                            self.vData[0][1], self.vData[1][1], self.toolOffset
                        )
                        pointThree = self.vData[2][1] - (self.vData[1][1] - pointThree)
                        self.storePoint(
                            "PU",
                            pointThree,
                            self.vData[2][2],
                            self.vData[2][3],
                            self.vData[2][4],
                        )
                    else:
                        # Else just write the 3rd entry
                        pointThree = self.vData[2][1]
                        self.storePoint(
                            "PU",
                            pointThree,
                            self.vData[2][2],
                            self.vData[2][3],
                            self.vData[2][4],
                        )
                    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
                        originalSegment = DirectedLineSegment(
                            self.vData[2][1], self.vData[3][1]
                        )
                        if originalSegment.length >= self.toolOffset:
                            pointFour = self.changeLength(
                                originalSegment.end,
                                originalSegment.start,
                                -self.toolOffset,
                            )
                        else:
                            pointFour = self.changeLength(
                                originalSegment.start,
                                originalSegment.end,
                                self.toolOffset - originalSegment.length,
                            )
                        # get angle start and angle vector
                        angleStart = DirectedLineSegment(
                            self.vData[2][1], pointThree
                        ).angle
                        angleVector = (
                            DirectedLineSegment(self.vData[2][1], pointFour).angle
                            - angleStart
                        )
                        # switch direction when arc is bigger than 180°
                        if angleVector > math.pi:
                            angleVector -= math.pi * 2
                        elif angleVector < -math.pi:
                            angleVector += math.pi * 2
                        # draw arc
                        if angleVector >= 0:
                            angle = angleStart + self.toolOffsetFlat
                            while angle < angleStart + angleVector:
                                self.storePoint(
                                    "PD",
                                    self.vData[2][1]
                                    + self.toolOffset
                                    * Vector2d(math.cos(angle), math.sin(angle)),
                                    self.vData[2][2],
                                    self.vData[2][3],
                                    self.vData[2][4],
                                )
                                angle += self.toolOffsetFlat
                        else:
                            angle = angleStart - self.toolOffsetFlat
                            while angle > angleStart + angleVector:
                                self.storePoint(
                                    "PD",
                                    self.vData[2][1]
                                    + self.toolOffset
                                    * Vector2d(math.cos(angle), math.sin(angle)),
                                    self.vData[2][2],
                                    self.vData[2][3],
                                    self.vData[2][4],
                                )
                                angle -= self.toolOffsetFlat
                        self.storePoint(
                            "PD",
                            pointFour,
                            self.vData[3][2],
                            self.vData[2][3],
                            self.vData[2][4],
                        )

    def storePoint(self, command, point, pen, speed, force):
        x = int(round(point.x))
        y = int(round(point.y))
        # skip when no change in movement
        if (
            self.lastPoint[0] == command
            and self.lastPoint[1] == x
            and self.lastPoint[2] == y
        ):
            return
        if self.dryRun:
            # find edges
            if self.divergenceX == "False" or x < self.divergenceX:
                self.divergenceX = x
            if self.divergenceY == "False" or y < self.divergenceY:
                self.divergenceY = y
            if self.sizeX == "False" or x > self.sizeX:
                self.sizeX = x
            if self.sizeY == "False" or y > self.sizeY:
                self.sizeY = y
        else:
            # store point
            if not self.options.center:
                # only positive values are allowed (usually)
                if x < 0:
                    x = 0
                if y < 0:
                    y = 0
            # select correct pen
            if self.lastPen != pen:
                self.hpgl += ";PU;SP%d" % pen
            if self.lastSpeed != speed:
                if speed > 0:
                    self.hpgl += ";VS%d" % speed
            if self.lastForce != force:
                if force > 0:
                    self.hpgl += ";FS%d" % force
            # do not repeat command
            if command == "PD" and self.lastPoint[0] == "PD" and self.lastPen == pen:
                self.hpgl += ",%d,%d" % (x, y)
            else:
                self.hpgl += ";%s%d,%d" % (command, x, y)
            self.lastPen = pen
            self.lastSpeed = speed
            self.lastForce = force
        self.lastPoint = [command, x, y]