deterministic svg output by sorting dict items

klaus · klaus · commit cb5893de95b9 · 2015-12-10T19:02:52.000+01:00
diff --git a/doc/api/backend_svg_api.rst b/doc/api/backend_svg_api.rst
@@ -0,0 +1,7 @@
+
+:mod:`matplotlib.backends.backend_svg`
+======================================
+
+.. automodule:: matplotlib.backends.backend_svg
+   :members:
+   :show-inheritance:
diff --git a/doc/api/index_backend_api.rst b/doc/api/index_backend_api.rst
@@ -12,6 +12,7 @@ backends
    backend_qt5agg_api.rst
    backend_wxagg_api.rst
    backend_pdf_api.rst
+   backend_svg_api.rst
 ..   backend_webagg.rst
    dviread.rst
    type1font.rst
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -17,7 +17,7 @@
 
 from matplotlib import cbook
 from matplotlib.cbook import (_check_1d, _string_to_bool, iterable,
-                              index_of, get_label)
+                              index_of, get_label, sorted_itervalues)
 from matplotlib import docstring
 import matplotlib.colors as mcolors
 import matplotlib.lines as mlines
@@ -33,7 +33,6 @@
 import matplotlib.image as mimage
 from matplotlib.offsetbox import OffsetBox
 from matplotlib.artist import allow_rasterization
-from matplotlib.cbook import iterable, index_of
 from matplotlib.rcsetup import cycler
 
 rcParams = matplotlib.rcParams
@@ -3687,7 +3686,7 @@ def get_children(self):
         children.extend(self.lines)
         children.extend(self.texts)
         children.extend(self.artists)
-        children.extend(six.itervalues(self.spines))
+        children.extend(sorted_itervalues(self.spines))
         children.append(self.xaxis)
         children.append(self.yaxis)
         children.append(self.title)
diff --git a/lib/matplotlib/backends/backend_svg.py b/lib/matplotlib/backends/backend_svg.py
@@ -17,7 +17,8 @@
 from matplotlib.backend_bases import RendererBase, GraphicsContextBase,\
      FigureManagerBase, FigureCanvasBase
 from matplotlib.backends.backend_mixed import MixedModeRenderer
-from matplotlib.cbook import is_string_like, is_writable_file_like, maxdict
+from matplotlib.cbook import (is_string_like, is_writable_file_like, maxdict,
+                              sorted_iteritems, sorted_itervalues)
 from matplotlib.colors import rgb2hex
 from matplotlib.figure import Figure
 from matplotlib.font_manager import findfont, FontProperties, get_font
@@ -358,7 +359,7 @@ def _write_hatches(self):
         HATCH_SIZE = 72
         writer = self.writer
         writer.start('defs')
-        for ((path, face, stroke), oid) in six.itervalues(self._hatchd):
+        for ((path, face, stroke), oid) in sorted_itervalues(self._hatchd):
             writer.start(
                 'pattern',
                 id=oid,
@@ -469,7 +470,7 @@ def _write_clips(self):
             return
         writer = self.writer
         writer.start('defs')
-        for clip, oid in six.itervalues(self._clipd):
+        for clip, oid in sorted_itervalues(self._clipd):
             writer.start('clipPath', id=oid)
             if len(clip) == 2:
                 clippath, clippath_trans = clip
@@ -488,7 +489,7 @@ def _write_svgfonts(self):
 
         writer = self.writer
         writer.start('defs')
-        for font_fname, chars in six.iteritems(self._fonts):
+        for font_fname, chars in sorted_iteritems(self._fonts):
             font = get_font(font_fname)
             font.set_size(72, 72)
             sfnt = font.get_sfnt()
@@ -829,7 +830,7 @@ def draw_image(self, gc, x, y, im, dx=None, dy=None, transform=None):
         if rcParams['svg.image_inline']:
             bytesio = io.BytesIO()
             _png.write_png(np.array(im)[::-1], bytesio)
-            oid = oid or self._make_id('image', bytesio)
+            oid = oid or self._make_id('image', bytesio.getvalue())
             attrib['xlink:href'] = (
                 "data:image/png;base64,\n" +
                 base64.b64encode(bytesio.getvalue()).decode('ascii'))
@@ -917,7 +918,7 @@ def _draw_text_as_path(self, gc, x, y, s, prop, angle, ismath, mtext=None):
 
             if glyph_map_new:
                 writer.start('defs')
-                for char_id, glyph_path in six.iteritems(glyph_map_new):
+                for char_id, glyph_path in sorted_iteritems(glyph_map_new):
                     path = Path(*glyph_path)
                     path_data = self._convert_path(path, simplify=False)
                     writer.element('path', id=char_id, d=path_data)
@@ -960,7 +961,7 @@ def _draw_text_as_path(self, gc, x, y, s, prop, angle, ismath, mtext=None):
             # used.
             if glyph_map_new:
                 writer.start('defs')
-                for char_id, glyph_path in six.iteritems(glyph_map_new):
+                for char_id, glyph_path in sorted_iteritems(glyph_map_new):
                     char_id = self._adjust_char_id(char_id)
                     # Some characters are blank
                     if not len(glyph_path[0]):
@@ -1104,7 +1105,7 @@ def _draw_text_as_text(self, gc, x, y, s, prop, angle, ismath, mtext=None):
                     fontset = self._fonts.setdefault(font.fname, set())
                     fontset.add(thetext)
 
-            for style, chars in six.iteritems(spans):
+            for style, chars in sorted_iteritems(spans):
                 chars.sort()
 
                 same_y = True
diff --git a/lib/matplotlib/cbook.py b/lib/matplotlib/cbook.py
@@ -2491,3 +2491,17 @@ def __exit__(self, exc_type, exc_value, traceback):
                     os.rmdir(path)
                 except OSError:
                     pass
+
+
+def sorted_iteritems(a):
+    """
+    Iterate over the items of a dictionary in an order defined by the keys
+    """
+    return ((k,v) for k,v in sorted(six.iteritems(a)))
+
+
+def sorted_itervalues(a):
+    """
+    Iterate over the values of a dictionary in an order defined by the keys
+    """
+    return (v for k,v in sorted_iteritems(a))
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -166,6 +166,16 @@ def validate_float_or_None(s):
         raise ValueError('Could not convert "%s" to float or None' % s)
 
 
+def validate_string_or_None(s):
+    """convert s to string or raise"""
+    if s is None:
+        return None
+    try:
+        return six.text_type(s)
+    except ValueError:
+        raise ValueError('Could not convert "%s" to string' % s)
+
+
 def validate_dpi(s):
     """confirm s is string 'figure' or convert s to float or raise"""
     if s == 'figure':
@@ -1165,7 +1175,7 @@ def validate_hist_bins(s):
     # True to save all characters as paths in the SVG
     'svg.embed_char_paths': [True, deprecate_svg_embed_char_paths],
     'svg.fonttype':         ['path', validate_svg_fonttype],
-    'svg.hashsalt':         [None, validate_any],
+    'svg.hashsalt':         [None, validate_string_or_None],
 
     # set this when you want to generate hardcopy docstring
     'docstring.hardcopy': [False, validate_bool],
diff --git a/lib/matplotlib/tests/test_backend_svg.py b/lib/matplotlib/tests/test_backend_svg.py
@@ -119,6 +119,48 @@ def test_bold_font_output_with_none_fonttype():
     ax.set_title('bold-title', fontweight='bold')
 
 
+def _test_determinism(filename):
+    # This function is mostly copy&paste from "def test_visibility"
+    # To require no GUI, we use Figure and FigureCanvasSVG
+    # instead of plt.figure and fig.savefig
+    from matplotlib.figure import Figure
+    from matplotlib.backends.backend_svg import FigureCanvasSVG
+    from matplotlib import rc
+    rc('svg', hashsalt='asdf')
+
+    fig = Figure()
+    ax = fig.add_subplot(111)
+
+    x = np.linspace(0, 4 * np.pi, 50)
+    y = np.sin(x)
+    yerr = np.ones_like(y)
+
+    a, b, c = ax.errorbar(x, y, yerr=yerr, fmt='ko')
+    for artist in b:
+        artist.set_visible(False)
+
+    FigureCanvasSVG(fig).print_svg(filename)
+
+
+@cleanup
+def test_determinism():
+    import os
+    import sys
+    from subprocess import check_call
+    from nose.tools import assert_equal
+    plots = []
+    for i in range(3):
+        check_call([sys.executable, '-R', '-c',
+                    'from matplotlib.tests.test_backend_svg '
+                    'import _test_determinism;'
+                    '_test_determinism("determinism.svg")'])
+        with open('determinism.svg', 'rb') as fd:
+            plots.append(fd.read())
+        os.unlink('determinism.svg')
+    for p in plots[1:]:
+        assert_equal(p, plots[0])
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)
diff --git a/matplotlibrc.template b/matplotlibrc.template
@@ -505,6 +505,8 @@ backend      : %(backend)s
 #    'path': Embed characters as paths -- supported by most SVG renderers
 #    'svgfont': Embed characters as SVG fonts -- supported only by Chrome,
 #               Opera and Safari
+#svg.hashsalt : None           # if not None, use this string as hash salt
+                               # instead of uuid4
 
 # docstring params
 #docstring.hardcopy = False  # set this when you want to generate hardcopy docstring
