from __future__ import division

import math
import os
import sys
import re
import shutil
import tempfile
import codecs
import atexit
import weakref

import matplotlib as mpl
from matplotlib.backend_bases import RendererBase, GraphicsContextBase,\
    FigureManagerBase, FigureCanvasBase
from matplotlib.backends.backend_mixed import MixedModeRenderer
from matplotlib.figure import Figure
from matplotlib.text import Text
from matplotlib.path import Path
from matplotlib import _png, rcParams
from matplotlib import font_manager
from matplotlib.ft2font import FT2Font
from matplotlib.cbook import is_string_like, is_writable_file_like
from matplotlib.compat import subprocess
from matplotlib.compat.subprocess import check_output


###############################################################################

# create a list of system fonts, all of these should work with xe/lua-latex
system_fonts = []
for f in font_manager.findSystemFonts():
    try:
        system_fonts.append(FT2Font(str(f)).family_name)
    except RuntimeError:
        pass  # some fonts on osx are known to fail, print?
    except:
        pass  # unknown error, skip this font


def get_texcommand():
    """Get chosen TeX system from rc."""
    texsystem_options = ["xelatex", "lualatex", "pdflatex"]
    texsystem = rcParams.get("pgf.texsystem", "xelatex")
    return texsystem if texsystem in texsystem_options else "xelatex"


def get_fontspec():
    """Build fontspec preamble from rc."""
    latex_fontspec = []
    texcommand = get_texcommand()

    if texcommand is not "pdflatex":
        latex_fontspec.append(r"\usepackage{fontspec}")

    if texcommand is not "pdflatex" and rcParams.get("pgf.rcfonts", True):
        # try to find fonts from rc parameters
        families = ["serif", "sans-serif", "monospace"]
        fontspecs = [r"\setmainfont{%s}", r"\setsansfont{%s}",
                     r"\setmonofont{%s}"]
        for family, fontspec in zip(families, fontspecs):
            matches = [f for f in rcParams["font." + family]
                       if f in system_fonts]
            if matches:
                latex_fontspec.append(fontspec % matches[0])
            else:
                pass  # no fonts found, fallback to LaTeX defaule

    return "\n".join(latex_fontspec)


def get_preamble():
    """Get LaTeX preamble from rc."""
    latex_preamble = rcParams.get("pgf.preamble", "")
    if type(latex_preamble) == list:
        latex_preamble = "\n".join(latex_preamble)
    return latex_preamble

###############################################################################

# This almost made me cry!!!
# In the end, it's better to use only one unit for all coordinates, since the
# arithmetic in latex seems to produce inaccurate conversions.
latex_pt_to_in = 1. / 72.27
latex_in_to_pt = 1. / latex_pt_to_in
mpl_pt_to_in = 1. / 72.
mpl_in_to_pt = 1. / mpl_pt_to_in

###############################################################################
# helper functions

NO_ESCAPE = r"(?<!\\)(?:\\\\)*"
re_mathsep = re.compile(NO_ESCAPE + r"\$")
re_escapetext = re.compile(NO_ESCAPE + "([_^$%])")
repl_escapetext = lambda m: "\\" + m.group(1)
re_mathdefault = re.compile(NO_ESCAPE + r"(\\mathdefault)")
repl_mathdefault = lambda m: m.group(0)[:-len(m.group(1))]


def common_texification(text):
    """
    Do some necessary and/or useful substitutions for texts to be included in
    LaTeX documents.
    """

    # Sometimes, matplotlib adds the unknown command \mathdefault.
    # Not using \mathnormal instead since this looks odd for the latex cm font.
    text = re_mathdefault.sub(repl_mathdefault, text)

    # split text into normaltext and inline math parts
    parts = re_mathsep.split(text)
    for i, s in enumerate(parts):
        if not i % 2:
            # textmode replacements
            s = re_escapetext.sub(repl_escapetext, s)
        else:
            # mathmode replacements
            s = r"\(\displaystyle %s\)" % s
        parts[i] = s

    return "".join(parts)


def writeln(fh, line):
    # every line of a file included with \input must be terminated with %
    # if not, latex will create additional vertical spaces for some reason
    fh.write(line)
    fh.write("%\n")


def _font_properties_str(prop):
    # translate font properties to latex commands, return as string
    commands = []

    families = {"serif": r"\rmfamily", "sans": r"\sffamily",
                "sans-serif": r"\sffamily", "monospace": r"\ttfamily"}
    family = prop.get_family()[0]
    if family in families:
        commands.append(families[family])
    elif family in system_fonts and get_texcommand() is not "pdflatex":
        commands.append(r"\setmainfont{%s}\rmfamily" % family)
    else:
        pass  # print warning?

    size = prop.get_size_in_points()
    commands.append(r"\fontsize{%f}{%f}" % (size, size * 1.2))

    styles = {"normal": r"", "italic": r"\itshape", "oblique": r"\slshape"}
    commands.append(styles[prop.get_style()])

    boldstyles = ["semibold", "demibold", "demi", "bold", "heavy",
                  "extra bold", "black"]
    if prop.get_weight() in boldstyles:
        commands.append(r"\bfseries")

    commands.append(r"\selectfont")
    return "".join(commands)


def make_pdf_to_png_converter():
    """
    Returns a function that converts a pdf file to a png file.
    """

    tools_available = []
    # check for pdftocairo
    try:
        check_output(["pdftocairo", "-v"], stderr=subprocess.STDOUT)
        tools_available.append("pdftocairo")
    except:
        pass
    # check for ghostscript
    try:
        gs = "gs" if sys.platform is not "win32" else "gswin32c"
        check_output([gs, "-v"], stderr=subprocess.STDOUT)
        tools_available.append("gs")
    except:
        pass

    # pick converter
    if "pdftocairo" in tools_available:
        def cairo_convert(pdffile, pngfile, dpi):
            cmd = ["pdftocairo", "-singlefile", "-png",
                   "-r %d" % dpi, pdffile, os.path.splitext(pngfile)[0]]
            # for some reason this doesn't work without shell
            check_output(" ".join(cmd), shell=True, stderr=subprocess.STDOUT)
        return cairo_convert
    elif "gs" in tools_available:
        def gs_convert(pdffile, pngfile, dpi):
            cmd = [gs, '-dQUIET', '-dSAFER', '-dBATCH', '-dNOPAUSE', '-dNOPROMPT',
                   '-sDEVICE=png16m', '-dUseCIEColor', '-dTextAlphaBits=4',
                   '-dGraphicsAlphaBits=4', '-dDOINTERPOLATE', '-sOutputFile=%s' % pngfile,
                   '-r%d' % dpi, pdffile]
            check_output(cmd, stderr=subprocess.STDOUT)
        return gs_convert
    else:
        raise RuntimeError("No suitable pdf to png renderer found.")


class LatexError(Exception):
    def __init__(self, message, latex_output=""):
        Exception.__init__(self, message)
        self.latex_output = latex_output


class LatexManagerFactory:
    previous_instance = None

    @staticmethod
    def get_latex_manager():
        texcommand = get_texcommand()
        latex_header = LatexManager._build_latex_header()
        prev = LatexManagerFactory.previous_instance

        # check if the previous instance of LatexManager can be reused
        if prev and prev.latex_header == latex_header and prev.texcommand == texcommand:
            if rcParams.get("pgf.debug", False):
                print "reusing LatexManager"
            return prev
        else:
            if rcParams.get("pgf.debug", False):
                print "creating LatexManager"
            new_inst = LatexManager()
            LatexManagerFactory.previous_instance = new_inst
            return new_inst

class WeakSet:
    # TODO: Poor man's weakref.WeakSet.
    #       Remove this once python 2.6 support is dropped from matplotlib.

    def __init__(self):
        self.weak_key_dict = weakref.WeakKeyDictionary()

    def add(self, item):
        self.weak_key_dict[item] = None

    def discard(self, item):
        if item in self.weak_key_dict:
            del self.weak_key_dict[item]

    def __iter__(self):
        return  self.weak_key_dict.iterkeys()


class LatexManager:
    """
    The LatexManager opens an instance of the LaTeX application for
    determining the metrics of text elements. The LaTeX environment can be
    modified by setting fonts and/or a custem preamble in the rc parameters.
    """
    _unclean_instances = WeakSet()

    @staticmethod
    def _build_latex_header():
        latex_preamble = get_preamble()
        latex_fontspec = get_fontspec()
        # Create LaTeX header with some content, else LaTeX will load some
        # math fonts later when we don't expect the additional output on stdout.
        # TODO: is this sufficient?
        latex_header = [r"\documentclass{minimal}",
                        latex_preamble,
                        latex_fontspec,
                        r"\begin{document}",
                        r"text $math \mu$",  # force latex to load fonts now
                        r"\typeout{pgf_backend_query_start}"]
        return "\n".join(latex_header)

    @staticmethod
    def _cleanup_remaining_instances():
        unclean_instances = list(LatexManager._unclean_instances)
        for latex_manager in unclean_instances:
            latex_manager._cleanup()

    def _stdin_writeln(self, s):
        self.latex_stdin_utf8.write(s)
        self.latex_stdin_utf8.write("\n")
        self.latex_stdin_utf8.flush()

    def _expect(self, s):
        exp = s.encode("utf8")
        buf = bytearray()
        while True:
            b = self.latex.stdout.read(1)
            buf += b
            if buf[-len(exp):] == exp:
                break
            if not len(b):
                raise LatexError("LaTeX process halted", buf.decode("utf8"))
        return buf.decode("utf8")

    def _expect_prompt(self):
        return self._expect("\n*")

    def __init__(self):
        # create a tmp directory for running latex, remember to cleanup
        self.tmpdir = tempfile.mkdtemp(prefix="mpl_pgf_lm_")
        LatexManager._unclean_instances.add(self)

        # test the LaTeX setup to ensure a clean startup of the subprocess
        self.texcommand = get_texcommand()
        self.latex_header = LatexManager._build_latex_header()
        latex_end = "\n\\makeatletter\n\\@@end\n"
        latex = subprocess.Popen([self.texcommand, "-halt-on-error"],
                                 stdin=subprocess.PIPE, stdout=subprocess.PIPE,
                                 cwd=self.tmpdir)
        test_input = self.latex_header + latex_end
        stdout, stderr = latex.communicate(test_input.encode("utf-8"))
        if latex.returncode != 0:
            raise LatexError("LaTeX returned an error, probably missing font or error in preamble:\n%s" % stdout)

        # open LaTeX process for real work
        latex = subprocess.Popen([self.texcommand, "-halt-on-error"],
                                 stdin=subprocess.PIPE, stdout=subprocess.PIPE,
                                 cwd=self.tmpdir)
        self.latex = latex
        self.latex_stdin_utf8 = codecs.getwriter("utf8")(self.latex.stdin)
        # write header with 'pgf_backend_query_start' token
        self._stdin_writeln(self._build_latex_header())
        # read all lines until our 'pgf_backend_query_start' token appears
        self._expect("*pgf_backend_query_start")
        self._expect_prompt()

        # cache for strings already processed
        self.str_cache = {}

    def _cleanup(self):
        if not os.path.isdir(self.tmpdir):
            return
        try:
            self.latex_stdin_utf8.close()
            self.latex.communicate()
            self.latex.wait()
        except:
            pass
        try:
            shutil.rmtree(self.tmpdir)
            LatexManager._unclean_instances.discard(self)
        except:
            sys.stderr.write("error deleting tmp directory %s\n" % self.tmpdir)

    def __del__(self):
        if rcParams.get("pgf.debug", False):
            print "deleting LatexManager"
        self._cleanup()

    def get_width_height_descent(self, text, prop):
        """
        Get the width, total height and descent for a text typesetted by the
        current LaTeX environment.
        """

        # apply font properties and define textbox
        prop_cmds = _font_properties_str(prop)
        textbox = "\\sbox0{%s %s}" % (prop_cmds, text)

        # check cache
        if textbox in self.str_cache:
            return self.str_cache[textbox]

        # send textbox to LaTeX and wait for prompt
        self._stdin_writeln(textbox)
        try:
            self._expect_prompt()
        except LatexError as e:
            msg = "Error processing '%s'\nLaTeX Output:\n%s"
            raise ValueError(msg % (text, e.latex_output))

        # typeout width, height and text offset of the last textbox
        self._stdin_writeln(r"\typeout{\the\wd0,\the\ht0,\the\dp0}")
        # read answer from latex and advance to the next prompt
        try:
            answer = self._expect_prompt()
        except LatexError as e:
            msg = "Error processing '%s'\nLaTeX Output:\n%s"
            raise ValueError(msg % (text, e.latex_output))

        # parse metrics from the answer string
        try:
            width, height, offset = answer.splitlines()[0].split(",")
        except:
            msg = "Error processing '%s'\nLaTeX Output:\n%s" % (text, answer)
            raise ValueError(msg)
        w, h, o = float(width[:-2]), float(height[:-2]), float(offset[:-2])

        # the height returned from LaTeX goes from base to top.
        # the height matplotlib expects goes from bottom to top.
        self.str_cache[textbox] = (w, h + o, o)
        return w, h + o, o


class RendererPgf(RendererBase):

    def __init__(self, figure, fh):
        """
        Creates a new PGF renderer that translates any drawing instruction
        into text commands to be interpreted in a latex pgfpicture environment.

        Attributes:
        * figure: Matplotlib figure to initialize height, width and dpi from.
        * fh: File handle for the output of the drawing commands.
        """
        RendererBase.__init__(self)
        self.dpi = figure.dpi
        self.fh = fh
        self.figure = figure
        self.image_counter = 0

        # get LatexManager instance
        self.latexManager = LatexManagerFactory.get_latex_manager()

    def draw_markers(self, gc, marker_path, marker_trans, path, trans, rgbFace=None):
        writeln(self.fh, r"\begin{pgfscope}")

        # convert from display units to in
        f = 1. / self.dpi

        # set style and clip
        self._print_pgf_clip(gc)
        self._print_pgf_path_styles(gc, rgbFace)

        # build marker definition
        bl, tr = marker_path.get_extents(marker_trans).get_points()
        coords = bl[0] * f, bl[1] * f, tr[0] * f, tr[1] * f
        writeln(self.fh, r"\pgfsys@defobject{currentmarker}{\pgfqpoint{%fin}{%fin}}{\pgfqpoint{%fin}{%fin}}{" % coords)
        self._print_pgf_path(None, marker_path, marker_trans)
        self._pgf_path_draw(stroke=gc.get_linewidth() != 0.0,
                            fill=rgbFace is not None)
        writeln(self.fh, r"}")

        # draw marker for each vertex
        for point, code in path.iter_segments(trans, simplify=False):
            x, y = point[0] * f, point[1] * f
            writeln(self.fh, r"\begin{pgfscope}")
            writeln(self.fh, r"\pgfsys@transformshift{%fin}{%fin}" % (x, y))
            writeln(self.fh, r"\pgfsys@useobject{currentmarker}{}")
            writeln(self.fh, r"\end{pgfscope}")

        writeln(self.fh, r"\end{pgfscope}")

    def draw_path(self, gc, path, transform, rgbFace=None):
        writeln(self.fh, r"\begin{pgfscope}")
        # draw the path
        self._print_pgf_clip(gc)
        self._print_pgf_path_styles(gc, rgbFace)
        self._print_pgf_path(gc, path, transform)
        self._pgf_path_draw(stroke=gc.get_linewidth() != 0.0,
                            fill=rgbFace is not None)
        writeln(self.fh, r"\end{pgfscope}")

        # if present, draw pattern on top
        if gc.get_hatch():
            writeln(self.fh, r"\begin{pgfscope}")
            self._print_pgf_path_styles(gc, rgbFace)

            # combine clip and path for clipping
            self._print_pgf_clip(gc)
            self._print_pgf_path(gc, path, transform)
            writeln(self.fh, r"\pgfusepath{clip}")

            # build pattern definition
            writeln(self.fh, r"\pgfsys@defobject{currentpattern}{\pgfqpoint{0in}{0in}}{\pgfqpoint{1in}{1in}}{")
            writeln(self.fh, r"\begin{pgfscope}")
            writeln(self.fh, r"\pgfpathrectangle{\pgfqpoint{0in}{0in}}{\pgfqpoint{1in}{1in}}")
            writeln(self.fh, r"\pgfusepath{clip}")
            scale = mpl.transforms.Affine2D().scale(self.dpi)
            self._print_pgf_path(None, gc.get_hatch_path(), scale)
            self._pgf_path_draw(stroke=True)
            writeln(self.fh, r"\end{pgfscope}")
            writeln(self.fh, r"}")
            # repeat pattern, filling the bounding rect of the path
            f = 1. / self.dpi
            (xmin, ymin), (xmax, ymax) = path.get_extents(transform).get_points()
            xmin, xmax = f * xmin, f * xmax
            ymin, ymax = f * ymin, f * ymax
            repx, repy = int(math.ceil(xmax-xmin)), int(math.ceil(ymax-ymin))
            writeln(self.fh, r"\pgfsys@transformshift{%fin}{%fin}" % (xmin, ymin))
            for iy in range(repy):
                for ix in range(repx):
                    writeln(self.fh, r"\pgfsys@useobject{currentpattern}{}")
                    writeln(self.fh, r"\pgfsys@transformshift{1in}{0in}")
                writeln(self.fh, r"\pgfsys@transformshift{-%din}{0in}" % repx)
                writeln(self.fh, r"\pgfsys@transformshift{0in}{1in}")

            writeln(self.fh, r"\end{pgfscope}")

    def _print_pgf_clip(self, gc):
        f = 1. / self.dpi
        # check for clip box
        bbox = gc.get_clip_rectangle()
        if bbox:
            p1, p2 = bbox.get_points()
            w, h = p2 - p1
            coords = p1[0] * f, p1[1] * f, w * f, h * f
            writeln(self.fh, r"\pgfpathrectangle{\pgfqpoint{%fin}{%fin}}{\pgfqpoint{%fin}{%fin}} " % coords)
            writeln(self.fh, r"\pgfusepath{clip}")

        # check for clip path
        clippath, clippath_trans = gc.get_clip_path()
        if clippath is not None:
            self._print_pgf_path(gc, clippath, clippath_trans)
            writeln(self.fh, r"\pgfusepath{clip}")

    def _print_pgf_path_styles(self, gc, rgbFace):
        # cap style
        capstyles = {"butt": r"\pgfsetbuttcap",
                     "round": r"\pgfsetroundcap",
                     "projecting": r"\pgfsetrectcap"}
        writeln(self.fh, capstyles[gc.get_capstyle()])

        # join style
        joinstyles = {"miter": r"\pgfsetmiterjoin",
                      "round": r"\pgfsetroundjoin",
                      "bevel": r"\pgfsetbeveljoin"}
        writeln(self.fh, joinstyles[gc.get_joinstyle()])

        # filling
        has_fill = rgbFace is not None

        if gc.get_forced_alpha():
            fillopacity = strokeopacity = gc.get_alpha()
        else:
            strokeopacity = gc.get_rgb()[3]
            fillopacity = rgbFace[3] if has_fill and len(rgbFace) > 3 else 1.0

        if has_fill:
            writeln(self.fh, r"\definecolor{currentfill}{rgb}{%f,%f,%f}" % tuple(rgbFace[:3]))
            writeln(self.fh, r"\pgfsetfillcolor{currentfill}")
        if has_fill and fillopacity != 1.0:
            writeln(self.fh, r"\pgfsetfillopacity{%f}" % fillopacity)

        # linewidth and color
        lw = gc.get_linewidth() * mpl_pt_to_in * latex_in_to_pt
        stroke_rgba = gc.get_rgb()
        writeln(self.fh, r"\pgfsetlinewidth{%fpt}" % lw)
        writeln(self.fh, r"\definecolor{currentstroke}{rgb}{%f,%f,%f}" % stroke_rgba[:3])
        writeln(self.fh, r"\pgfsetstrokecolor{currentstroke}")
        if strokeopacity != 1.0:
            writeln(self.fh, r"\pgfsetstrokeopacity{%f}" % strokeopacity)

        # line style
        dash_offset, dash_list = gc.get_dashes()
        if dash_list is None:
            writeln(self.fh, r"\pgfsetdash{}{0pt}")
        else:
            dash_str = r"\pgfsetdash{"
            for dash in dash_list:
                dash_str += r"{%fpt}" % dash
            dash_str += r"}{%fpt}" % dash_offset
            writeln(self.fh, dash_str)

    def _print_pgf_path(self, gc, path, transform):
        f = 1. / self.dpi
        # check for clip box
        bbox = gc.get_clip_rectangle() if gc else None
        if bbox:
            p1, p2 = bbox.get_points()
            clip = (p1[0], p1[1], p2[0], p2[1])
        else:
            clip = None
        # build path
        for points, code in path.iter_segments(transform, clip=clip):
            if code == Path.MOVETO:
                x, y = tuple(points)
                writeln(self.fh, r"\pgfpathmoveto{\pgfqpoint{%fin}{%fin}}" %
                        (f * x, f * y))
            elif code == Path.CLOSEPOLY:
                writeln(self.fh, r"\pgfpathclose")
            elif code == Path.LINETO:
                x, y = tuple(points)
                writeln(self.fh, r"\pgfpathlineto{\pgfqpoint{%fin}{%fin}}" %
                        (f * x, f * y))
            elif code == Path.CURVE3:
                cx, cy, px, py = tuple(points)
                coords = cx * f, cy * f, px * f, py * f
                writeln(self.fh, r"\pgfpathquadraticcurveto{\pgfqpoint{%fin}{%fin}}{\pgfqpoint{%fin}{%fin}}" % coords)
            elif code == Path.CURVE4:
                c1x, c1y, c2x, c2y, px, py = tuple(points)
                coords = c1x * f, c1y * f, c2x * f, c2y * f, px * f, py * f
                writeln(self.fh, r"\pgfpathcurveto{\pgfqpoint{%fin}{%fin}}{\pgfqpoint{%fin}{%fin}}{\pgfqpoint{%fin}{%fin}}" % coords)

    def _pgf_path_draw(self, stroke=True, fill=False):
        actions = []
        if stroke:
            actions.append("stroke")
        if fill:
            actions.append("fill")
        writeln(self.fh, r"\pgfusepath{%s}" % ",".join(actions))

    def draw_image(self, gc, x, y, im):
        # TODO: Almost no documentation for the behavior of this function.
        #       Something missing?

        # save the images to png files
        path = os.path.dirname(self.fh.name)
        fname = os.path.splitext(os.path.basename(self.fh.name))[0]
        fname_img = "%s-img%d.png" % (fname, self.image_counter)
        self.image_counter += 1
        im.flipud_out()
        rows, cols, buf = im.as_rgba_str()
        _png.write_png(buf, cols, rows, os.path.join(path, fname_img))

        # reference the image in the pgf picture
        writeln(self.fh, r"\begin{pgfscope}")
        self._print_pgf_clip(gc)
        h, w = im.get_size_out()
        f = 1. / self.dpi  # from display coords to inch
        writeln(self.fh, r"\pgftext[at=\pgfqpoint{%fin}{%fin},left,bottom]{\pgfimage[interpolate=true,width=%fin,height=%fin]{%s}}" % (x * f, y * f, w * f, h * f, fname_img))
        writeln(self.fh, r"\end{pgfscope}")

    def draw_tex(self, gc, x, y, s, prop, angle, ismath="TeX!", mtext=None):
        self.draw_text(gc, x, y, s, prop, angle, ismath, mtext)

    def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
        # prepare string for tex
        s = common_texification(s)
        prop_cmds = _font_properties_str(prop)
        s = ur"{%s %s}" % (prop_cmds, s)


        writeln(self.fh, r"\begin{pgfscope}")

        alpha = gc.get_alpha()
        if alpha != 1.0:
            writeln(self.fh, r"\pgfsetfillopacity{%f}" % alpha)
            writeln(self.fh, r"\pgfsetstrokeopacity{%f}" % alpha)
        rgb = tuple(gc.get_rgb())[:3]
        if rgb != (0, 0, 0):
            writeln(self.fh, r"\definecolor{textcolor}{rgb}{%f,%f,%f}" % rgb)
            writeln(self.fh, r"\pgfsetstrokecolor{textcolor}")
            writeln(self.fh, r"\pgfsetfillcolor{textcolor}")

        f = 1.0 / self.figure.dpi
        text_args = []
        if angle == 0 or mtext.get_rotation_mode() == "anchor":
            # if text anchoring can be supported, get the original coordinates
            # and add alignment information
            x, y = mtext.get_transform().transform_point(mtext.get_position())
            text_args.append("x=%fin" % (x * f))
            text_args.append("y=%fin" % (y * f))

            halign = {"left": "left", "right": "right", "center": ""}
            valign = {"top": "top", "bottom": "bottom",
                      "baseline": "base", "center": ""}
            text_args.append(halign[mtext.get_ha()])
            text_args.append(valign[mtext.get_va()])
        else:
            # if not, use the text layout provided by matplotlib
            text_args.append("x=%fin" % (x * f))
            text_args.append("y=%fin" % (y * f))
            text_args.append("left")
            text_args.append("base")

        if angle != 0:
            text_args.append("rotate=%f" % angle)

        writeln(self.fh, r"\pgftext[%s]{%s}" % (",".join(text_args), s))
        writeln(self.fh, r"\end{pgfscope}")

    def get_text_width_height_descent(self, s, prop, ismath):
        # check if the math is supposed to be displaystyled
        s = common_texification(s)

        # get text metrics in units of latex pt, convert to display units
        w, h, d = self.latexManager.get_width_height_descent(s, prop)
        # TODO: this should be latex_pt_to_in instead of mpl_pt_to_in
        # but having a little bit more space around the text looks better,
        # plus the bounding box reported by LaTeX is VERY narrow
        f = mpl_pt_to_in * self.dpi
        return w * f, h * f, d * f

    def flipy(self):
        return False

    def get_canvas_width_height(self):
        return self.figure.get_figwidth(), self.figure.get_figheight()

    def points_to_pixels(self, points):
        return points * mpl_pt_to_in * self.dpi

    def new_gc(self):
        return GraphicsContextPgf()


class GraphicsContextPgf(GraphicsContextBase):
    pass

########################################################################


def draw_if_interactive():
    pass


def new_figure_manager(num, *args, **kwargs):
    """
    Create a new figure manager instance
    """
    # if a main-level app must be created, this is the usual place to
    # do it -- see backend_wx, backend_wxagg and backend_tkagg for
    # examples.  Not all GUIs require explicit instantiation of a
    # main-level app (egg backend_gtk, backend_gtkagg) for pylab
    FigureClass = kwargs.pop('FigureClass', Figure)
    thisFig = FigureClass(*args, **kwargs)
    return new_figure_manager_given_figure(num, thisFig)


def new_figure_manager_given_figure(num, figure):
    """
    Create a new figure manager instance for the given figure.
    """
    canvas = FigureCanvasPgf(figure)
    manager = FigureManagerPgf(canvas, num)
    return manager


class TmpDirCleaner:
    remaining_tmpdirs = set()

    @staticmethod
    def add(tmpdir):
        TmpDirCleaner.remaining_tmpdirs.add(tmpdir)

    @staticmethod
    def cleanup_remaining_tmpdirs():
        for tmpdir in TmpDirCleaner.remaining_tmpdirs:
            try:
                shutil.rmtree(tmpdir)
            except:
                sys.stderr.write("error deleting tmp directory %s\n" % tmpdir)


class FigureCanvasPgf(FigureCanvasBase):
    filetypes = {"pgf": "LaTeX PGF picture",
                 "pdf": "LaTeX compiled PGF picture",
                 "png": "Portable Network Graphics", }

    def __init__(self, *args):
        FigureCanvasBase.__init__(self, *args)

    def get_default_filetype(self):
        return 'pdf'

    def _print_pgf_to_fh(self, fh, *args, **kwargs):
        header_text = r"""%% Creator: Matplotlib, PGF backend
%%
%% To include the figure in your LaTeX document, write
%%   \input{<filename>.pgf}
%%
%% Make sure the required packages are loaded in your preamble
%%   \usepackage{pgf}
%%
%% Figures using additional raster images can only be included by \input if
%% they are in the same directory as the main LaTeX file. For loading figures
%% from other directories you can use the `import` package
%%   \usepackage{import}
%% and then include the figures with
%%   \import{<path to file>}{<filename>.pgf}
%%
"""

        # append the preamble used by the backend as a comment for debugging
        header_info_preamble = ["%% Matplotlib used the following preamble"]
        for line in get_preamble().splitlines():
            header_info_preamble.append("%%   " + line)
        for line in get_fontspec().splitlines():
            header_info_preamble.append("%%   " + line)
        header_info_preamble.append("%%")
        header_info_preamble = "\n".join(header_info_preamble)

        # get figure size in inch
        w, h = self.figure.get_figwidth(), self.figure.get_figheight()
        dpi = self.figure.get_dpi()

        # create pgfpicture environment and write the pgf code
        fh.write(header_text)
        fh.write(header_info_preamble)
        fh.write("\n")
        writeln(fh, r"\begingroup")
        writeln(fh, r"\makeatletter")
        writeln(fh, r"\begin{pgfpicture}")
        writeln(fh, r"\pgfpathrectangle{\pgfpointorigin}{\pgfqpoint{%fin}{%fin}}" % (w, h))
        writeln(fh, r"\pgfusepath{use as bounding box}")
        _bbox_inches_restore = kwargs.pop("bbox_inches_restore", None)
        renderer = MixedModeRenderer(self.figure, w, h, dpi,
                                     RendererPgf(self.figure, fh),
                                     bbox_inches_restore=_bbox_inches_restore)
        self.figure.draw(renderer)

        # end the pgfpicture environment
        writeln(fh, r"\end{pgfpicture}")
        writeln(fh, r"\makeatother")
        writeln(fh, r"\endgroup")

    def print_pgf(self, fname_or_fh, *args, **kwargs):
        """
        Output pgf commands for drawing the figure so it can be included and
        rendered in latex documents.
        """
        if kwargs.get("dryrun", False):
            return

        # figure out where the pgf is to be written to
        if is_string_like(fname_or_fh):
            with codecs.open(fname_or_fh, "w", encoding="utf-8") as fh:
                self._print_pgf_to_fh(fh, *args, **kwargs)
        elif is_writable_file_like(fname_or_fh):
            raise ValueError("saving pgf to a stream is not supported, " +
                             "consider using the pdf option of the pgf-backend")
        else:
            raise ValueError("filename must be a path")

    def _print_pdf_to_fh(self, fh, *args, **kwargs):
        w, h = self.figure.get_figwidth(), self.figure.get_figheight()

        try:
            # create temporary directory for compiling the figure
            tmpdir = tempfile.mkdtemp(prefix="mpl_pgf_")
            fname_pgf = os.path.join(tmpdir, "figure.pgf")
            fname_tex = os.path.join(tmpdir, "figure.tex")
            fname_pdf = os.path.join(tmpdir, "figure.pdf")

            # print figure to pgf and compile it with latex
            self.print_pgf(fname_pgf, *args, **kwargs)

            latex_preamble = get_preamble()
            latex_fontspec = get_fontspec()
            latexcode = r"""
\documentclass[12pt]{minimal}
\usepackage[paperwidth=%fin, paperheight=%fin, margin=0in]{geometry}
%s
%s
\usepackage{pgf}

\begin{document}
\centering
\input{figure.pgf}
\end{document}""" % (w, h, latex_preamble, latex_fontspec)
            with codecs.open(fname_tex, "w", "utf-8") as fh_tex:
                fh_tex.write(latexcode)

            texcommand = get_texcommand()
            cmdargs = [texcommand, "-interaction=nonstopmode",
                       "-halt-on-error", "figure.tex"]
            try:
                check_output(cmdargs, stderr=subprocess.STDOUT, cwd=tmpdir)
            except subprocess.CalledProcessError as e:
                raise RuntimeError("%s was not able to process your file.\n\nFull log:\n%s" % (texcommand, e.output))

            # copy file contents to target
            with open(fname_pdf, "rb") as fh_src:
                shutil.copyfileobj(fh_src, fh)
        finally:
            try:
                shutil.rmtree(tmpdir)
            except:
                TmpDirCleaner.add(tmpdir)

    def print_pdf(self, fname_or_fh, *args, **kwargs):
        """
        Use LaTeX to compile a Pgf generated figure to PDF.
        """
        # figure out where the pdf is to be written to
        if is_string_like(fname_or_fh):
            with open(fname_or_fh, "wb") as fh:
                self._print_pdf_to_fh(fh, *args, **kwargs)
        elif is_writable_file_like(fname_or_fh):
            self._print_pdf_to_fh(fname_or_fh, *args, **kwargs)
        else:
            raise ValueError("filename must be a path or a file-like object")

    def _print_png_to_fh(self, fh, *args, **kwargs):
        converter = make_pdf_to_png_converter()

        try:
            # create temporary directory for pdf creation and png conversion
            tmpdir = tempfile.mkdtemp(prefix="mpl_pgf_")
            fname_pdf = os.path.join(tmpdir, "figure.pdf")
            fname_png = os.path.join(tmpdir, "figure.png")
            # create pdf and try to convert it to png
            self.print_pdf(fname_pdf, *args, **kwargs)
            converter(fname_pdf, fname_png, dpi=self.figure.dpi)
            # copy file contents to target
            with open(fname_png, "rb") as fh_src:
                shutil.copyfileobj(fh_src, fh)
        finally:
            try:
                shutil.rmtree(tmpdir)
            except:
                TmpDirCleaner.add(tmpdir)

    def print_png(self, fname_or_fh, *args, **kwargs):
        """
        Use LaTeX to compile a pgf figure to pdf and convert it to png.
        """
        if is_string_like(fname_or_fh):
            with open(fname_or_fh, "wb") as fh:
                self._print_png_to_fh(fh, *args, **kwargs)
        elif is_writable_file_like(fname_or_fh):
            self._print_png_to_fh(fname_or_fh, *args, **kwargs)
        else:
            raise ValueError("filename must be a path or a file-like object")

    def get_renderer(self):
        return RendererPgf(self.figure, None)


class FigureManagerPgf(FigureManagerBase):
    def __init__(self, *args):
        FigureManagerBase.__init__(self, *args)

########################################################################

FigureManager = FigureManagerPgf

def _cleanup_all():
    LatexManager._cleanup_remaining_instances()
    TmpDirCleaner.cleanup_remaining_tmpdirs()

atexit.register(_cleanup_all)
