Lazy import of private modules

mdboom · mdboom · commit d104c743e25f · 2018-11-08T17:14:07.000-05:00
diff --git a/lib/matplotlib/backends/backend_agg.py b/lib/matplotlib/backends/backend_agg.py
@@ -38,7 +38,6 @@
 from matplotlib import colors as mcolors
 
 from matplotlib.backends._backend_agg import RendererAgg as _RendererAgg
-from matplotlib import _png
 
 from matplotlib.backend_bases import _has_pil
 
@@ -502,6 +501,8 @@ def print_png(self, filename_or_obj, *args, **kwargs):
                 https://www.w3.org/TR/2003/REC-PNG-20031110/#11keywords
 
         """
+        from matplotlib import _png
+
         FigureCanvasAgg.draw(self)
         renderer = self.get_renderer()
 
diff --git a/lib/matplotlib/contour.py b/lib/matplotlib/contour.py
@@ -8,7 +8,6 @@
 from numpy import ma
 
 import matplotlib as mpl
-import matplotlib._contour as _contour
 import matplotlib.path as mpath
 import matplotlib.ticker as ticker
 import matplotlib.cm as cm
@@ -1481,6 +1480,8 @@ def _process_args(self, *args, **kwargs):
             self._mins = args[0]._mins
             self._maxs = args[0]._maxs
         else:
+            import matplotlib._contour as contour
+
             self._corner_mask = kwargs.pop('corner_mask', None)
             if self._corner_mask is None:
                 self._corner_mask = mpl.rcParams['contour.corner_mask']
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -21,7 +21,6 @@
 
 # For clarity, names from _image are given explicitly in this module:
 import matplotlib._image as _image
-import matplotlib._png as _png
 
 # For user convenience, the names from _image are also imported into
 # the image namespace:
@@ -613,6 +612,7 @@ def contains(self, mouseevent):
 
     def write_png(self, fname):
         """Write the image to png file with fname"""
+        from matplotlib import _png
         im = self.to_rgba(self._A[::-1] if self.origin == 'lower' else self._A,
                           bytes=True, norm=True)
         _png.write_png(im, fname)
@@ -1340,7 +1340,11 @@ def imread(fname, format=None):
     .. _Pillow documentation: http://pillow.readthedocs.io/en/latest/
     """
 
-    handlers = {'png': _png.read_png, }
+    def read_png(*args, **kwargs):
+        from matplotlib import _png
+        return _png.read_png(*args, **kwargs)
+
+    handlers = {'png': read_png, }
     if format is None:
         if isinstance(fname, str):
             parsed = urllib.parse.urlparse(fname)
diff --git a/lib/matplotlib/mathtext.py b/lib/matplotlib/mathtext.py
@@ -31,7 +31,7 @@
 
 ParserElement.enablePackrat()
 
-from matplotlib import _png, cbook, colors as mcolors, get_data_path, rcParams
+from matplotlib import cbook, colors as mcolors, get_data_path, rcParams
 from matplotlib.afm import AFM
 from matplotlib.cbook import get_realpath_and_stat
 from matplotlib.ft2font import FT2Image, KERNING_DEFAULT, LOAD_NO_HINTING
@@ -3446,6 +3446,7 @@ def to_png(self, filename, texstr, color='black', dpi=120, fontsize=14):
         Returns the offset of the baseline from the bottom of the
         image in pixels.
         """
+        from matplotlib import _png
         rgba, depth = self.to_rgba(
             texstr, color=color, dpi=dpi, fontsize=fontsize)
         _png.write_png(rgba, filename)
diff --git a/lib/matplotlib/tri/triangulation.py b/lib/matplotlib/tri/triangulation.py
@@ -1,8 +1,5 @@
 import numpy as np
 
-import matplotlib._tri as _tri
-import matplotlib._qhull as _qhull
-
 
 class Triangulation(object):
     """
@@ -39,6 +36,8 @@ class Triangulation(object):
     triangles formed from colinear points, or overlapping triangles.
     """
     def __init__(self, x, y, triangles=None, mask=None):
+        from matplotlib import _qhull
+
         self.x = np.asarray(x, dtype=np.float64)
         self.y = np.asarray(y, dtype=np.float64)
         if self.x.shape != self.y.shape or self.x.ndim != 1:
@@ -106,6 +105,7 @@ def get_cpp_triangulation(self):
         Return the underlying C++ Triangulation object, creating it
         if necessary.
         """
+        from matplotlib import _tri
         if self._cpp_triangulation is None:
             self._cpp_triangulation = _tri.Triangulation(
                 self.x, self.y, self.triangles, self.mask, self._edges,
