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collections.py

00001 """
Classes for the efficient drawing of large collections of objects that
share most properties, eg a large number of line segments or polygons

The classes are not meant to be as flexible as their single element
counterparts (eg you may not be able to select all line styles) but
they are meant to be fast for common use cases (eg a bunch of solid
line segemnts)
"""
import math, warnings
from matplotlib import rcParams, verbose

from artist import Artist
from backend_bases import GraphicsContextBase
from cbook import is_string_like, iterable
from colors import colorConverter
from cm import ScalarMappable
from numerix import arange, sin, cos, pi, asarray, sqrt, array, newaxis, ones
from transforms import identity_transform

00021 class Collection(Artist):
    """
    All properties in a collection must be sequences.  The
    property of the ith element of the collection is the

      prop[i % len(props)].

    This implies that the properties cycle if the len of props is less
    than the number of elements of the collection.  A length 1
    property is shared by all the elements of the collection

    All color args to a collection are sequences of rgba tuples
    """

    def __init__(self):
        Artist.__init__(self)


    def get_verts(self):
        'return seq of (x,y) in collection'
        raise NotImplementedError('Derived must override')

    def _get_value(self, val):
        try: return (float(val), )
        except TypeError:
            if iterable(val) and len(val):
                try: float(val[0])
                except TypeError: pass # raise below
                else: return val

        raise TypeError('val must be a float or nonzero sequence of floats')

00053 class PatchCollection(Collection, ScalarMappable):
    """
    Base class for filled regions such as PolyCollection etc.
    It must be subclassed to be usable.

    kwargs are:

          edgecolors=None,
          facecolors=None,
          linewidths=None,
          antialiaseds = None,
          offsets = None,
          transOffset = identity_transform(),
          norm = None,  # optional for ScalarMappable
          cmap = None,  # ditto

    offsets and transOffset are used to translate the patch after
    rendering (default no offsets)

    If any of edgecolors, facecolors, linewidths, antialiaseds are
    None, they default to their patch.* rc params setting, in sequence
    form.

    The use of ScalarMappable is optional.  If the ScalarMappable
    matrix _A is not None (ie a call to set_array has been made), at
    draw time a call to scalar mappable will be made to set the face
    colors.
    """
    zorder = 1
    def __init__(self,
                 edgecolors=None,
                 facecolors=None,
                 linewidths=None,
                 antialiaseds = None,
                 offsets = None,
                 transOffset = identity_transform(),
                 norm = None,  # optional for ScalarMappable
                 cmap = None,  # ditto
                 ):
        Collection.__init__(self)
        ScalarMappable.__init__(self, norm, cmap)

        if facecolors is None: facecolors = rcParams['patch.facecolor']
        if edgecolors is None: edgecolors = rcParams['patch.edgecolor']
        if linewidths is None: linewidths = (rcParams['patch.linewidth'],)
        if antialiaseds is None: antialiaseds = (rcParams['patch.antialiased'],)

        self._facecolors  = colorConverter.to_rgba_list(facecolors)
        if edgecolors == 'None':
            self._edgecolors = self._facecolors
            linewidths = (0,)
        else:
            self._edgecolors = colorConverter.to_rgba_list(edgecolors)
        self._linewidths  = linewidths
        self._antialiaseds = antialiaseds
        self._offsets = offsets
        self._transOffset = transOffset


00112     def set_linewidth(self, lw):
        """
        Set the linewidth(s) for the collection.  lw can be a scalar or a
        sequence; if it is a sequence the patches will cycle through the
        sequence

        ACCEPTS: float or sequence of floats
        """
        self._linewidths = self._get_value(lw)

00122     def set_color(self, c):
        """
        Set both the edgecolor and the facecolor.
        See set_facecolor and set_edgecolor.

        ACCEPTS: matplotlib color arg or sequence of rgba tuples
        """
        self.set_facecolor(c)
        self.set_edgecolor(c)

00132     def set_facecolor(self, c):
        """
        Set the facecolor(s) of the collection.  c can be a matplotlib
        color arg (all patches have same color), or a a sequence or
        rgba tuples; if it is a sequence the patches will cycle
        through the sequence

        ACCEPTS: matplotlib color arg or sequence of rgba tuples
        """
        self._facecolors = colorConverter.to_rgba_list(c)

00143     def set_edgecolor(self, c):
        """
        Set the facecolor(s) of the collection. c can be a matplotlib color
        arg (all patches have same color), or a a sequence or rgba tuples; if
        it is a sequence the patches will cycle through the sequence

        ACCEPTS: matplotlib color arg or sequence of rgba tuples
        """
        self._edgecolors = colorConverter.to_rgba_list(c)

00153     def set_alpha(self, alpha):
        """
        Set the alpha tranpancies of the collection.  Alpha must be
        a float.

        ACCEPTS: float
        """
        try: float(alpha)
        except TypeError: raise TypeError('alpha must be a float')
        else:
            Artist.set_alpha(self, alpha)
            self._facecolors = [(r,g,b,alpha) for r,g,b,a in self._facecolors]
            if is_string_like(self._edgecolors) and self._edgecolors != 'None':
                self._edgecolors = [(r,g,b,alpha) for r,g,b,a in self._edgecolors]

00168     def update_scalarmappable(self):
        """
        If the scalar mappable array is not none, update facecolors
        from scalar data
        """
        #print 'update_scalarmappable: self._A', self._A
        if self._A is None: return
        if len(self._A.shape)>1:
            raise ValueError('PatchCollections can only map rank 1 arrays')
        self._facecolors = self.to_rgba(self._A, self._alpha)
        #print self._facecolors

00180 class QuadMesh(PatchCollection):
    """
    Class for the efficient drawing of a quadrilateral mesh.
    A quadrilateral mesh consists of a grid of vertices. The dimensions
    of this array are (meshWidth+1, meshHeight+1). Each vertex in
    the mesh has a different set of "mesh coordinates" representing
    its position in the topology of the mesh. For any values (m, n)
    such that 0 <= m <= meshWidth and 0 <= n <= meshHeight, the
    vertices at mesh coordinates (m, n), (m, n+1), (m+1, n+1), and
    (m+1, n) form one of the quadrilaterals in the mesh. There are
    thus (meshWidth * meshHeight) quadrilaterals in the mesh.
    The mesh need not be regular and the polygons need not be convex.
    A quadrilateral mesh is represented by a
    (2 x ((meshWidth + 1) * (meshHeight + 1))) Numeric array
    'coordinates' where each row is the X and Y coordinates of one
    of the vertices.
    To define the function that maps from a data point to
    its corresponding color, use the set_cmap() function.
    Each of these arrays is indexed in row-major order by the
    mesh coordinates of the vertex (or the mesh coordinates of
    the lower left vertex, in the case of the colors). For example,
    the first entry in coordinates is the coordinates of the vertex
    at mesh coordinates (0, 0), then the one at (0, 1), then at
    (0, 2) .. (0, meshWidth), (1, 0), (1, 1), and so on.
    """
    def __init__(self, meshWidth, meshHeight, coordinates, showedges):
        PatchCollection.__init__(self)
        self._meshWidth = meshWidth
        self._meshHeight = meshHeight
        self._coordinates = coordinates
        self._showedges = showedges

    def get_verts(self, dataTrans=None):
        return self._coordinates;

    def draw(self, renderer):
        # does not call update_scalarmappable, need to update it
        # when creating/changing              ****** Why not?  speed?
        if not self.get_visible(): return
        self._transform.freeze()
        self._transOffset.freeze()
        #print 'QuadMesh draw'
        self.update_scalarmappable()  #######################

        renderer.draw_quad_mesh( self._meshWidth, self._meshHeight,
            self._facecolors, self._coordinates[:,0],
            self._coordinates[:, 1], self.clipbox, self._transform,
            self._offsets, self._transOffset, self._showedges)
        self._transform.thaw()
        self._transOffset.thaw()

class PolyCollection(PatchCollection):
    def __init__(self, verts, **kwargs):
        """
        verts is a sequence of ( verts0, verts1, ...) where verts_i is
        a sequence of xy tuples of vertices, or an equivalent
        numerix array of shape (nv,2).
        See PatchCollection for kwargs.
        """
        PatchCollection.__init__(self,**kwargs)
        self._verts = verts

    def set_verts(self, verts):
        '''This allows one to delay initialization of the vertices.'''
        self._verts = verts

    def draw(self, renderer):
        if not self.get_visible(): return
        renderer.open_group('polycollection')
        self._transform.freeze()
        self._transOffset.freeze()
        self.update_scalarmappable()
        if is_string_like(self._edgecolors) and self._edgecolors[:2] == 'No':
            self._linewidths = (0,)
            #self._edgecolors = self._facecolors
        renderer.draw_poly_collection(
            self._verts, self._transform, self.clipbox,
            self._facecolors, self._edgecolors,
            self._linewidths, self._antialiaseds,
            self._offsets,  self._transOffset)
        self._transform.thaw()
        self._transOffset.thaw()
        renderer.close_group('polycollection')


    def get_verts(self, dataTrans=None):
        '''Return vertices in data coordinates.
        The calculation is incomplete in general; it is based
        on the vertices or the offsets, whichever is using
        dataTrans as its transformation, so it does not take
        into account the combined effect of segments and offsets.
        '''
        verts = []
        if self._offsets is None:
            for seg in self._verts:
                verts.extend(seg)
            return [tuple(xy) for xy in verts]
        if self._transOffset == dataTrans:
            return [tuple(xy) for xy in self._offsets]
        raise NotImplementedError('Vertices in data coordinates are calculated\n'
                + 'with offsets only if _transOffset == dataTrans.')


class RegularPolyCollection(PatchCollection):
    def __init__(self,
                 dpi,
                 numsides,
                 rotation = 0 ,
                 sizes = (1,),
                 **kwargs):
        """
        Draw a regular polygon with numsides.

        * dpi is the figure dpi instance, and is required to do the
          area scaling.

        * numsides: the number of sides of the polygon

        * sizes gives the area of the circle circumscribing the
          regular polygon in points^2

        * rotation is the rotation of the polygon in radians

        kwargs: See PatchCollection for more details

          * offsets are a sequence of x,y tuples that give the centers of
            the polygon in data coordinates

          * transOffset is the Transformation instance used to
            transform the centers onto the canvas.

        Example: see examples/dynamic_collection.py for complete example

        offsets = nx.mlab.rand(20,2)
        facecolors = [cm.jet(x) for x in nx.mlab.rand(20)]
        black = (0,0,0,1)

        collection = RegularPolyCollection(
            fig.dpi,
            numsides=5, # a pentagon
            rotation=0,
            sizes=(50,),
            facecolors = facecolors,
            edgecolors = (black,),
            linewidths = (1,),
            offsets = offsets,
            transOffset = ax.transData,
            )


        """
        PatchCollection.__init__(self,**kwargs)
        self._sizes = sizes
        self._dpi = dpi
        self.numsides = numsides
        self.rotation = rotation
        self._update_verts()

    def _update_verts(self):
        r = 1.0/math.sqrt(math.pi)  # unit area
        theta = (2*math.pi/self.numsides)*arange(self.numsides) + self.rotation
        self._verts = zip( r*sin(theta), r*cos(theta) )

    def draw(self, renderer):
        if not self.get_visible(): return
        renderer.open_group('regpolycollection')
        self._transform.freeze()
        self._transOffset.freeze()
        self.update_scalarmappable()
        self._update_verts()
        scales = sqrt(asarray(self._sizes)*self._dpi.get()/72.0)

        if is_string_like(self._edgecolors) and self._edgecolors[:2] == 'No':
            #self._edgecolors = self._facecolors
            self._linewidths = (0,)
        renderer.draw_regpoly_collection(
            self.clipbox,
            self._offsets, self._transOffset,
            self._verts, scales,
            self._facecolors, self._edgecolors,
            self._linewidths, self._antialiaseds)

        self._transform.thaw()
        self._transOffset.thaw()
        renderer.close_group('regpolycollection')


    def get_verts(self, dataTrans=None):
        '''Return vertices in data coordinates.
        The calculation is incomplete; it uses only
        the offsets, and only if _transOffset is dataTrans.
        '''
        if self._transOffset == dataTrans:
            return [tuple(xy) for xy in self._offsets]
        raise NotImplementedError('Vertices in data coordinates are calculated\n'
                + 'only with offsets and only if _transOffset == dataTrans.')

class StarPolygonCollection(RegularPolyCollection):
    def __init__(self,
                 dpi,
                 numsides,
                 rotation = 0 ,
                 sizes = (1,),
                 **kwargs):
        """
        Draw a regular star like Polygone with numsides.
        
        * dpi is the figure dpi instance, and is required to do the
          area scaling.

        * numsides: the number of sides of the polygon

        * sizes gives the area of the circle circumscribing the
          regular polygon in points^2

        * rotation is the rotation of the polygon in radians

        kwargs: See PatchCollection for more details

          * offsets are a sequence of x,y tuples that give the centers of
            the polygon in data coordinates

          * transOffset is the Transformation instance used to
            transform the centers onto the canvas.
        """
        RegularPolyCollection.__init__(self, dpi, numsides, rotation, sizes, **kwargs)
    
    def _update_verts(self):
        scale = 1.0/math.sqrt(math.pi)
        r = scale*ones(self.numsides*2)
        r[1::2] *= 0.5
        theta  = (2.*math.pi/(2*self.numsides))*arange(2*self.numsides) + self.rotation
        self._verts = zip( r*sin(theta), r*cos(theta) )

00414 class LineCollection(Collection, ScalarMappable):
    """
    All parameters must be sequences.  The property of the ith line
    segment is the prop[i % len(props)], ie the properties cycle if
    the len of props is less than the number of sements
    """
    zorder = 2
00421     def __init__(self, segments,     # Can be None.
                 linewidths    = None,
                 colors        = None,
                 antialiaseds  = None,
                 linestyle = 'solid',
                 offsets = None,
                 transOffset = None,#identity_transform(),
                 norm = None,
                 cmap = None,
                 ):
        """
        segments is a sequence of ( line0, line1, line2), where
        linen = (x0, y0), (x1, y1), ... (xm, ym), or the
        equivalent numerix array with two columns.
        Each line can be a different length.

        colors must be a tuple of RGBA tuples (eg arbitrary color
        strings, etc, not allowed).

        antialiaseds must be a sequence of ones or zeros

        linestyles is a string or dash tuple. Legal string values are
          solid|dashed|dashdot|dotted.  The dash tuple is (offset, onoffseq)
          where onoffseq is an even length tuple of on and off ink in points.

        If linewidths, colors, or antialiaseds is None, they default to
        their rc params setting, in sequence form.

        If offsets and transOffset are not None, then
        offsets are transformed by transOffset and applied after
        the segments have been transformed to display coordinates.

        If offsets is not None but transOffset is None, then the
        offsets are added to the segments before any transformation.
        In this case, a single offset can be specified as offsets=(xo,yo),
        and this value will be
        added cumulatively to each successive segment, so as
        to produce a set of successively offset curves.

        norm = None,  # optional for ScalarMappable
        cmap = None,  # ditto

        The use of ScalarMappable is optional.  If the ScalarMappable
        matrix _A is not None (ie a call to set_array has been made), at
        draw time a call to scalar mappable will be made to set the colors.
        """

        Collection.__init__(self)
        ScalarMappable.__init__(self, norm, cmap)

        if linewidths is None   :
            linewidths   = (rcParams['lines.linewidth'], )

        if colors is None       :
            colors       = (rcParams['lines.color'],)
        if antialiaseds is None :
            antialiaseds = (rcParams['lines.antialiased'], )

        self._colors = colorConverter.to_rgba_list(colors)
        self._aa = antialiaseds
        self._lw = linewidths
        self.set_linestyle(linestyle)
        self._uniform_offsets = None
        if offsets is not None:
            offsets = asarray(offsets)
            if len(offsets.shape) == 1:
                offsets = offsets[newaxis,:]  # Make it Nx2.
        if transOffset is None:
            if offsets is not None:
                self._uniform_offsets = offsets
                offsets = None
            transOffset = identity_transform()
        self._offsets = offsets
        self._transOffset = transOffset
        self.set_segments(segments)

    def set_segments(self, segments):
        if segments is None: return
        self._segments = [asarray(seg) for seg in segments]
        if self._uniform_offsets is not None:
            self._add_offsets()

    set_verts = set_segments # for compatibility with PolyCollection

    def _add_offsets(self):
        segs = self._segments
        offsets = self._uniform_offsets
        Nsegs = len(segs)
        Noffs = offsets.shape[0]
        if Noffs == 1:
            for i in range(Nsegs):
                segs[i] = segs[i] + i * offsets
        else:
            for i in range(Nsegs):
                io = i%Noffs
                segs[i] = segs[i] + offsets[io:io+1]


    def draw(self, renderer):
        if not self.get_visible(): return
        renderer.open_group('linecollection')
        self._transform.freeze()
        if self._transOffset is not None: self._transOffset.freeze()
        self.update_scalarmappable()
        renderer.draw_line_collection(
            self._segments, self._transform, self.clipbox,
            self._colors, self._lw, self._ls, self._aa, self._offsets,
            self._transOffset)
        self._transform.thaw()
        if self._transOffset is not None: self._transOffset.thaw()
        renderer.close_group('linecollection')

00533     def set_linewidth(self, lw):
        """
        Set the linewidth(s) for the collection.  lw can be a scalar or a
        sequence; if it is a sequence the patches will cycle through the
        sequence

        ACCEPTS: float or sequence of floats
        """

        self._lw = self._get_value(lw)

00544     def set_linestyle(self, ls):
        """
        Set the linestyles(s) for the collection.
        ACCEPTS: ['solid' | 'dashed', 'dashdot', 'dotted' |  (offset, on-off-dash-seq) ]
        """
        if is_string_like(ls):
            dashes = GraphicsContextBase.dashd[ls]
        elif iterable(ls) and len(ls)==2:
            dashes = ls
        else: raise ValueError('Do not know how to convert %s to dashes'%ls)


        self._ls = dashes

00558     def set_color(self, c):
        """
        Set the color(s) of the line collection.  c can be a
        matplotlib color arg (all patches have same color), or a a
        sequence or rgba tuples; if it is a sequence the patches will
        cycle through the sequence

        ACCEPTS: matplotlib color arg or sequence of rgba tuples
        """
        self._colors = colorConverter.to_rgba_list(c)

00569     def color(self, c):
        """
        Set the color(s) of the line collection.  c can be a
        matplotlib color arg (all patches have same color), or a a
        sequence or rgba tuples; if it is a sequence the patches will
        cycle through the sequence

        ACCEPTS: matplotlib color arg or sequence of rgba tuples
        """
        warnings.warn('LineCollection.color deprecated; use set_color instead')
        return self.set_color(c)

00581     def set_alpha(self, alpha):
        """
        Set the alpha tranpancies of the collection.  Alpha can be a
        float, in which case it is applied to the entire collection,
        or a sequence of floats

        ACCEPTS: float or sequence of floats
        """

        try: float(alpha)
        except TypeError: raise TypeError('alpha must be a float')
        else:
            Artist.set_alpha(self, alpha)
            self._colors = [(r,g,b,alpha) for r,g,b,a in self._colors]

    def get_linewidth(self):
        return self._lw

    def get_linestyle(self):
        return self._ls

    def get_dashes(self):
        return self._ls

    def get_colors(self):
        return self._colors

00608     def get_verts(self, dataTrans=None):
        '''Return vertices in data coordinates.
        The calculation is incomplete in general; it is based
        on the segments or the offsets, whichever is using
        dataTrans as its transformation, so it does not take
        into account the combined effect of segments and offsets.
        '''
        verts = []
        if self._offsets is None:
            for seg in self._segments:
                verts.extend(seg)
            return [tuple(xy) for xy in verts]
        if self._transOffset == dataTrans:
            return [tuple(xy) for xy in self._offsets]
        raise NotImplementedError('Vertices in data coordinates are calculated\n'
                + 'with offsets only if _transOffset == dataTrans.')

00625     def update_scalarmappable(self):
        """
        If the scalar mappable array is not none, update colors
        from scalar data
        """
        if self._A is None: return
        if len(self._A.shape)>1:
            raise ValueError('LineCollections can only map rank 1 arrays')
        self._colors = self.to_rgba(self._A, self._alpha)




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