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backend_emf.py

00001 """
Enhanced Metafile backend.  See http://pyemf.sourceforge.net for the EMF
driver library.
"""

from __future__ import division

try:
    import pyemf
except ImportError:
    import sys
    print >>sys.stderr, 'You must first install pyemf from http://pyemf.sf.net'
    sys.exit()

import os,sys,math,re

from matplotlib import verbose, __version__, rcParams

from matplotlib._pylab_helpers import Gcf
from matplotlib.backend_bases import RendererBase, GraphicsContextBase,\
     FigureManagerBase, FigureCanvasBase
from matplotlib.cbook import enumerate
from matplotlib.figure import Figure
from matplotlib.transforms import Bbox

from matplotlib.font_manager import findfont, FontProperties
from matplotlib.ft2font import FT2Font, KERNING_UNFITTED, KERNING_DEFAULT, KERNING_UNSCALED

# Font handling stuff snarfed from backend_ps, but only using TTF fonts
_fontd = {}

# Debug print stuff
debugHandle = False
debugPrint = False
debugText = False

# Hashable font properties class.  In EMF, angle of rotation is a part
# of the font properties, so a handle to a new font must be obtained
# if the rotation changes.
class EMFFontProperties(FontProperties):
    def __init__(self,other,angle):
        FontProperties.__init__(self,other.get_family(),
                              other.get_style(),
                              other.get_variant(),
                              other.get_weight(),
                              other.get_stretch(),
                              other.get_size())
        self.__angle=angle

    def __hash__(self):
        return hash( (FontProperties.__hash__(self), self.__angle))

    def __str__(self):
        return str( (FontProperties.__str__(self), self.__angle))

    def set_angle(self,angle):
        self.__angle=angle

# Hashable pen (line style) properties.
class EMFPen:
    def __init__(self,emf,gc):
        self.emf=emf
        self.gc=gc

        r,g,b=gc.get_rgb()
        self.r=int(r*255)
        self.g=int(g*255)
        self.b=int(b*255)
        self.width=int(gc.get_linewidth())

        self.style=0
        self.set_linestyle()
        if debugHandle: print "EMFPen: style=%d width=%d rgb=(%d,%d,%d)" % (self.style,self.width,self.r,self.g,self.b)

    def __hash__(self):
        return hash((self.style,self.width,self.r,self.g,self.b))

    def set_linestyle(self):
        # Hack.  Negative width lines will not get drawn.
        if self.width<0:
            self.style=pyemf.PS_NULL
        else:
            styles={'solid':pyemf.PS_SOLID, 'dashed':pyemf.PS_DASH,
                    'dashdot':pyemf.PS_DASHDOT, 'dotted':pyemf.PS_DOT}
            #style=styles.get(self.gc.get_linestyle('solid'))
            style=self.gc.get_linestyle('solid')
            if debugHandle: print "EMFPen: style=%d" % style
            if style in styles:
                self.style=styles[style]
            else:
                self.style=pyemf.PS_SOLID

    def get_handle(self):
        handle=self.emf.CreatePen(self.style,self.width,(self.r,self.g,self.b))
        return handle

# Hashable brush (fill style) properties.
class EMFBrush:
    def __init__(self,emf,rgb):
        self.emf=emf
        r,g,b=rgb
        self.r=int(r*255)
        self.g=int(g*255)
        self.b=int(b*255)
        if debugHandle: print "EMFBrush: rgb=(%d,%d,%d)" % (self.r,self.g,self.b)

    def __hash__(self):
        return hash((self.r,self.g,self.b))

    def get_handle(self):
        handle=self.emf.CreateSolidBrush((self.r,self.g,self.b))
        return handle




00117 class RendererEMF(RendererBase):
    """
    The renderer handles drawing/rendering operations through a
    pyemf.EMF instance.
    """
    def __init__(self, outfile, width, height, dpi):
        "Initialize the renderer with a gd image instance"
        self.outfile = outfile

        # a map from get_color args to colors
        self._cached = {}

        # dict of hashed properties to already created font handles
        self._fontHandle = {}

        self.lastHandle = {'font':-1, 'pen':-1, 'brush':-1}

        self.emf=pyemf.EMF(width,height,dpi,'in')

        self.width=int(width*dpi)
        self.height=int(height*dpi)
        self.dpi = dpi
        self.pointstodpi = dpi/72.0
        self.hackPointsForMathExponent = 2.0

        # set background transparent for text
        self.emf.SetBkMode(pyemf.TRANSPARENT)
        # set baseline for text to be bottom left corner
        self.emf.SetTextAlign( pyemf.TA_BOTTOM|pyemf.TA_LEFT)

        if debugPrint: print "RendererEMF: (%f,%f) %s dpi=%f" % (self.width,self.height,outfile,dpi)



    def save(self):
        self.emf.save(self.outfile)

00154     def draw_arc(self, gcEdge, rgbFace, x, y, width, height, angle1, angle2, rotation):
        """
        Draw an arc using GraphicsContext instance gcEdge, centered at x,y,
        with width and height and angles from 0.0 to 360.0
        0 degrees is at 3-o'clock
        positive angles are anti-clockwise

        If the color rgbFace is not None, fill the arc with it.
        """
        if debugPrint: print "draw_arc: (%f,%f) angles=(%f,%f) w,h=(%f,%f)" % (x,y,angle1,angle2,width,height)
        pen=self.select_pen(gcEdge)
        brush=self.select_brush(rgbFace)

        # This algorithm doesn't work very well on small circles
        # because of rounding error.  This shows up most obviously on
        # legends where the circles are small anyway, and it is
        # compounded by the fact that it puts several circles right
        # next to each other so the differences are obvious.
        hw=width/2
        hh=height/2
        x1=int(x-width/2)
        y1=int(y-height/2)
        if brush:
            self.emf.Pie(int(x-hw),int(self.height-(y-hh)),int(x+hw),int(self.height-(y+hh)),int(x+math.cos(angle1*math.pi/180.0)*hw),int(self.height-(y+math.sin(angle1*math.pi/180.0)*hh)),int(x+math.cos(angle2*math.pi/180.0)*hw),int(self.height-(y+math.sin(angle2*math.pi/180.0)*hh)))
        else:
            self.emf.Arc(int(x-hw),int(self.height-(y-hh)),int(x+hw),int(self.height-(y+hh)),int(x+math.cos(angle1*math.pi/180.0)*hw),int(self.height-(y+math.sin(angle1*math.pi/180.0)*hh)),int(x+math.cos(angle2*math.pi/180.0)*hw),int(self.height-(y+math.sin(angle2*math.pi/180.0)*hh)))


00182     def draw_image(self, x, y, im, bbox):
        """
        Draw the Image instance into the current axes; x is the
        distance in pixels from the left hand side of the canvas. y is
        the distance from the origin.  That is, if origin is upper, y
        is the distance from top.  If origin is lower, y is the
        distance from bottom

        bbox is a matplotlib.transforms.BBox instance for clipping, or
        None
        """

        # pyemf2 currently doesn't support bitmaps.

        pass


00199     def draw_line(self, gc, x1, y1, x2, y2):
        """
        Draw a single line from x1,y1 to x2,y2
        """
        if debugPrint: print "draw_line: (%f,%f) - (%f,%f)" % (x1,y1,x2,y2)

        if self.select_pen(gc):
            self.emf.Polyline([(long(x1),long(self.height-y1)),(long(x2),long(self.height-y2))])
        else:
            if debugPrint: print "draw_line: optimizing away (%f,%f) - (%f,%f)" % (x1,y1,x2,y2)

00210     def draw_lines(self, gc, x, y):
        """
        x and y are equal length arrays, draw lines connecting each
        point in x, y
        """
        if debugPrint: print "draw_lines: %d points" % len(str(x))

        # optimize away anything that won't actually be drawn.  Edge
        # style must not be PS_NULL for it to appear on screen.
        if self.select_pen(gc):
            points = [(long(x[i]), long(self.height-y[i])) for i in range(len(x))]
            self.emf.Polyline(points)

00223     def draw_point(self, gc, x, y):
        """
        Draw a single point at x,y
        Where 'point' is a device-unit point (or pixel), not a matplotlib point
        """
        if debugPrint: print "draw_point: (%f,%f)" % (x,y)

        # don't cache this pen
        pen=EMFPen(self.emf,gc)

        self.emf.SetPixel(long(x),long(self.height-y),(pen.r,pen.g,pen.b))

00235     def draw_polygon(self, gcEdge, rgbFace, points):
        """
        Draw a polygon using the GraphicsContext instance gc.
        points is a len vertices tuple, each element
        giving the x,y coords a vertex

        If the color rgbFace is not None, fill the polygon with it
        """
        if debugPrint: print "draw_polygon: %d points" % len(points)

        # optimize away anything that won't actually draw.  Either a
        # face color or edge style must be defined
        pen=self.select_pen(gcEdge)
        brush=self.select_brush(rgbFace)
        if pen or brush:
            points = [(long(x), long(self.height-y)) for x,y in points]
            self.emf.Polygon(points)
        else:
            points = [(long(x), long(self.height-y)) for x,y in points]
            if debugPrint: print "draw_polygon: optimizing away polygon: %d points = %s" % (len(points),str(points))

00256     def draw_rectangle(self, gcEdge, rgbFace, x, y, width, height):
        """
        Draw a non-filled rectangle using the GraphicsContext instance gcEdge,
        with lower left at x,y with width and height.

        If rgbFace is not None, fill the rectangle with it.
        """
        if debugPrint: print "draw_rectangle: (%f,%f) w=%f,h=%f" % (x,y,width,height)

        # optimize away anything that won't actually draw.  Either a
        # face color or edge style must be defined
        pen=self.select_pen(gcEdge)
        brush=self.select_brush(rgbFace)
        if pen or brush:
            self.emf.Rectangle(int(x),int(self.height-y),int(x)+int(width),int(self.height-y)-int(height))
        else:
            if debugPrint: print "draw_rectangle: optimizing away (%f,%f) w=%f,h=%f" % (x,y,width,height)


00275     def draw_text(self, gc, x, y, s, prop, angle, ismath=False):
        """
        Draw the text.Text instance s at x,y (display coords) with font
        properties instance prop at angle in degrees, using GraphicsContext gc

        **backend implementers note**

        When you are trying to determine if you have gotten your bounding box
        right (which is what enables the text layout/alignment to work
        properly), it helps to change the line in text.py

                  if 0: bbox_artist(self, renderer)

        to if 1, and then the actual bounding box will be blotted along with
        your text.
        """
        if debugText: print "draw_text: (%f,%f) %d degrees: '%s'" % (x,y,angle,s)
        if ismath:
            self.draw_math_text(gc,x,y,s,prop,angle)
        else:
            self.draw_plain_text(gc,x,y,s,prop,angle)


00298     def draw_plain_text(self, gc, x, y, s, prop, angle):
        """
        Draw a text string verbatim; no conversion is done.
        """
        if debugText: print "draw_plain_text: (%f,%f) %d degrees: '%s'" % (x,y,angle,s)
        if debugText: print " properties:\n"+str(prop)
        self.select_font(prop,angle)

        # haxor follows!  The subtleties of text placement in EMF
        # still elude me a bit.  It always seems to be too high on the
        # page, about 10 pixels too high on a 300dpi resolution image.
        # So, I'm adding this hack for the moment:
        hackoffsetper300dpi=10
        xhack=math.sin(angle*math.pi/180.0)*hackoffsetper300dpi*self.dpi/300.0
        yhack=math.cos(angle*math.pi/180.0)*hackoffsetper300dpi*self.dpi/300.0

        self.emf.TextOut(long(x+xhack),long(y+yhack),s)


00317     def draw_math_text(self, gc, x, y, s, prop, angle):
        """
        Draw a subset of TeX, currently handles exponents only.  Since
        pyemf doesn't have any raster functionality yet, the
        texmanager.get_rgba won't help.
        """
        if debugText: print "draw_math_text: (%f,%f) %d degrees: '%s'" % (x,y,angle,s)

        s = s[1:-1]  # strip the $ from front and back
        match=re.match("10\^\{(.+)\}",s)
        if match:
            exp=match.group(1)
            if debugText: print " exponent=%s" % exp
            font = self._get_font_ttf(prop)
            font.set_text("10", 0.0)
            w, h = font.get_width_height()
            w /= 64.0  # convert from subpixels
            h /= 64.0
            self.draw_plain_text(gc,x,y,"10",prop,angle)
            propexp=prop.copy()
            propexp.set_size(prop.get_size_in_points()*.8)
            self.draw_plain_text(gc,x+w+self.points_to_pixels(self.hackPointsForMathExponent),y-(h/2),exp,propexp,angle)
        else:
            # if it isn't an exponent, then render the raw TeX string.
            self.draw_plain_text(gc,x,y,s,prop,angle)

00343     def get_math_text_width_height(self, s, prop):
        """
        get the width and height in display coords of the string s
        with FontPropertry prop, ripped right out of backend_ps.  This
        method must be kept in sync with draw_math_text.
        """
        if debugText: print "get_math_text_width_height:"
        s = s[1:-1]  # strip the $ from front and back
        match=re.match("10\^\{(.+)\}",s)
        if match:
            exp=match.group(1)
            if debugText: print " exponent=%s" % exp
            font = self._get_font_ttf(prop)
            font.set_text("10", 0.0)
            w1, h1 = font.get_width_height()

            propexp=prop.copy()
            propexp.set_size(prop.get_size_in_points()*.8)
            fontexp=self._get_font_ttf(propexp)
            fontexp.set_text(exp, 0.0)
            w2, h2 = fontexp.get_width_height()
            w=w1+w2
            h=h1+(h2/2)
            w /= 64.0  # convert from subpixels
            h /= 64.0
            w+=self.points_to_pixels(self.hackPointsForMathExponent)
            if debugText: print " math string=%s w,h=(%f,%f)" % (s, w, h)
        else:
            w,h=self.get_text_width_height(s,prop,False)
        return w, h


00375     def flipy(self):
        """return true if y small numbers are top for renderer
        Is used for drawing text (text.py) and images (image.py) only
        """
        return True


00382     def get_canvas_width_height(self):
        """
        return the canvas width and height in display coords
        """
        return self.width,self.height


00389     def set_handle(self,type,handle):
        """
        Update the EMF file with the current handle, but only if it
        isn't the same as the last one.  Don't want to flood the file
        with duplicate info.
        """
        if self.lastHandle[type] != handle:
            self.emf.SelectObject(handle)
            self.lastHandle[type]=handle


00400     def get_font_handle(self, prop, angle):
        """
        Look up the handle for the font based on the dict of
        properties *and* the rotation angle, since in EMF the font
        rotation is a part of the font definition.
        """
        prop=EMFFontProperties(prop,angle)
        size=int(prop.get_size_in_points()*self.pointstodpi)
        face=prop.get_name()
        key = hash(prop)
        handle = self._fontHandle.get(key)
        if handle is None:
            handle=self.emf.CreateFont(-size, 0, int(angle)*10, int(angle)*10,
                                   pyemf.FW_NORMAL, 0, 0, 0,
                          pyemf.ANSI_CHARSET, pyemf.OUT_DEFAULT_PRECIS,
                          pyemf.CLIP_DEFAULT_PRECIS, pyemf.DEFAULT_QUALITY,
                          pyemf.DEFAULT_PITCH | pyemf.FF_DONTCARE, face);
            if debugHandle: print "get_font_handle: creating handle=%d for face=%s size=%d" % (handle,face,size)
            self._fontHandle[key]=handle
        if debugHandle: print " found font handle %d for face=%s size=%d" % (handle,face,size)
        self.set_handle("font",handle)
        return handle


    def select_font(self,prop,angle):
        handle=self.get_font_handle(prop,angle)
        self.set_handle("font",handle)


00429     def select_pen(self, gc):
        """
        Select a pen that includes the color, line width and line
        style.  Return the pen if it will draw a line, or None if the
        pen won't produce any output (i.e. the style is PS_NULL)
        """
        pen=EMFPen(self.emf,gc)
        key=hash(pen)
        handle=self._fontHandle.get(key)
        if handle is None:
            handle=pen.get_handle()
            self._fontHandle[key]=handle
        if debugHandle: print " found pen handle %d" % handle
        self.set_handle("pen",handle)
        if pen.style != pyemf.PS_NULL:
            return pen
        else:
            return None


00449     def select_brush(self, rgb):
        """
        Select a fill color, and return the brush if the color is
        valid or None if this won't produce a fill operation.
        """
        if rgb is not None:
            brush=EMFBrush(self.emf,rgb)
            key=hash(brush)
            handle=self._fontHandle.get(key)
            if handle is None:
                handle=brush.get_handle()
                self._fontHandle[key]=handle
            if debugHandle: print " found brush handle %d" % handle
            self.set_handle("brush",handle)
            return brush
        else:
            return None


00468     def _get_font_ttf(self, prop):
        """
        get the true type font properties, used because EMFs on
        windows will use true type fonts.
        """
        key = hash(prop)
        font = _fontd.get(key)
        if font is None:
            fname = findfont(prop)
            if debugText: print "_get_font_ttf: name=%s" % fname
            font = FT2Font(str(fname))
            _fontd[key] = font
        font.clear()
        size = prop.get_size_in_points()
        font.set_size(size, self.dpi)

        return font


00487     def get_text_width_height(self, s, prop, ismath):
        """
        get the width and height in display coords of the string s
        with FontPropertry prop, ripped right out of backend_ps
        """
        if debugText: print "get_text_width_height: ismath=%s properties: %s" % (str(ismath),str(prop))
        if ismath:
            if debugText: print " MATH TEXT! = %s" % str(ismath)
            w,h = self.get_math_text_width_height(s, prop)
            return w,h

        font = self._get_font_ttf(prop)
        font.set_text(s, 0.0)
        w, h = font.get_width_height()
        w /= 64.0  # convert from subpixels
        h /= 64.0
        if debugText: print " text string=%s w,h=(%f,%f)" % (s, w, h)
        return w, h


00507     def new_gc(self):
        return GraphicsContextEMF()

00510     def points_to_pixels(self, points):
        # if backend doesn't have dpi, eg, postscript or svg
        #return points
        # elif backend assumes a value for pixels_per_inch
        #return points/72.0 * self.dpi.get() * pixels_per_inch/72.0
        # else
        return points/72.0 * self.dpi


00519 class GraphicsContextEMF(GraphicsContextBase):
    """
    The graphics context provides the color, line styles, etc...  See the gtk
    and postscript backends for examples of mapping the graphics context
    attributes (cap styles, join styles, line widths, colors) to a particular
    backend.  In GTK this is done by wrapping a gtk.gdk.GC object and
    forwarding the appropriate calls to it using a dictionary mapping styles
    to gdk constants.  In Postscript, all the work is done by the renderer,
    mapping line styles to postscript calls.

    If it's more appropriate to do the mapping at the renderer level (as in
    the postscript backend), you don't need to override any of the GC methods.
    If it's more appropriate to wrap an instance (as in the GTK backend) and
    do the mapping here, you'll need to override several of the setter
    methods.

    The base GraphicsContext stores colors as a RGB tuple on the unit
    interval, eg, (0.5, 0.0, 1.0). You may need to map this to colors
    appropriate for your backend.
    """
    pass



########################################################################
#
# The following functions and classes are for pylab and implement
# window/figure managers, etc...
#
########################################################################

00550 def draw_if_interactive():
    """
    For image backends - is not required
    For GUI backends - this should be overriden if drawing should be done in
    interactive python mode
    """
    pass

00558 def show():
    """
    For image backends - is not required
    For GUI backends - show() is usually the last line of a pylab script and
    tells the backend that it is time to draw.  In interactive mode, this may
    be a do nothing func.  See the GTK backend for an example of how to handle
    interactive versus batch mode
    """
    for manager in Gcf.get_all_fig_managers():
        # do something to display the GUI
        pass


00571 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)
    canvas = FigureCanvasEMF(thisFig)
    manager = FigureManagerEMF(canvas, num)
    return manager


00586 class FigureCanvasEMF(FigureCanvasBase):
    """
    The canvas the figure renders into.  Calls the draw and print fig
    methods, creates the renderers, etc...

    Public attribute

      figure - A Figure instance
    """

00596     def draw(self):
        """
        Draw the figure using the renderer
        """
        pass

    filetypes = {'emf': 'Enhanced Metafile'}
    
    def print_emf(self, filename, dpi=300, **kwargs):
        width, height = self.figure.get_size_inches()
        renderer = RendererEMF(filename,width,height,dpi)
        self.figure.draw(renderer)
        renderer.save()

    def get_default_filetype(self):
        return 'emf'
        
00613 class FigureManagerEMF(FigureManagerBase):
    """
    Wrap everything up into a window for the pylab interface

    For non interactive backends, the base class does all the work
    """
    pass

########################################################################
#
# Now just provide the standard names that backend.__init__ is expecting
#
########################################################################


FigureManager = FigureManagerEMF


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