backend_ps cleanup.

anntzer · anntzer · commit f4d742f2f784 · 2020-03-04T11:36:29.000+01:00
Dedupe some code between backend_ps and backend_bases (the edgecolor and
facecolor handling -- see changelog), as well as between the non-tex and
tex cases (by formatting the header metadata ("dsc_comments") earlier).

Also simplify a bit papersize handling in usetex case.
diff --git a/doc/api/next_api_changes/behaviour.rst b/doc/api/next_api_changes/behaviour.rst
@@ -100,4 +100,15 @@ deprecation warning.
 
 Previously setting the *ecolor* would turn off automatic color cycling for the plot, leading to the 
 the lines and markers defaulting to whatever the first color in the color cycle was in the case of 
-multiple plot calls. 
+multiple plot calls. 
+
+`.FigureCanvasPS.print_ps` and `.FigureCanvasPS.print_eps` no longer apply edgecolor and facecolor
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+These methods now assume that the figure edge and facecolor have been correctly
+applied by `.FigureCanvasBase.print_figure`, as they are normally called
+through it.
+
+This behavior is consistent with other figure saving methods
+(`.FigureCanvasAgg.print_png`, `.FigureCanvasPdf.print_pdf`,
+`.FigureCanvasSVG.print_svg`).
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
@@ -764,10 +764,29 @@ def print_ps(self, outfile, *args, **kwargs):
     def print_eps(self, outfile, *args, **kwargs):
         return self._print_ps(outfile, 'eps', *args, **kwargs)
 
-    def _print_ps(self, outfile, format, *args,
-                  papertype=None, dpi=72, facecolor='w', edgecolor='w',
-                  orientation='portrait',
-                  **kwargs):
+    def _print_ps(
+            self, outfile, format, *args,
+            dpi=72, metadata=None, papertype=None, orientation='portrait',
+            **kwargs):
+
+        self.figure.set_dpi(72)  # Override the dpi kwarg
+
+        dsc_comments = {}
+        if isinstance(outfile, (str, os.PathLike)):
+            dsc_comments["Title"] = \
+                os.fspath(outfile).encode("ascii", "replace").decode("ascii")
+        dsc_comments["Creator"] = (metadata or {}).get(
+            "Creator",
+            f"matplotlib version {mpl.__version__}, http://matplotlib.org/")
+        source_date_epoch = os.getenv("SOURCE_DATE_EPOCH")
+        dsc_comments["CreationDate"] = (
+            datetime.datetime.utcfromtimestamp(
+                int(source_date_epoch)).strftime("%a %b %d %H:%M:%S %Y")
+            if source_date_epoch
+            else time.ctime())
+        dsc_comments = "\n".join(
+            f"%%{k}: {v}" for k, v in dsc_comments.items())
+
         if papertype is None:
             papertype = mpl.rcParams['ps.papersize']
         papertype = papertype.lower()
@@ -776,42 +795,29 @@ def _print_ps(self, outfile, format, *args,
         orientation = cbook._check_getitem(
             _Orientation, orientation=orientation.lower())
 
-        self.figure.set_dpi(72)  # Override the dpi kwarg
-
         printer = (self._print_figure_tex
                    if mpl.rcParams['text.usetex'] else
                    self._print_figure)
-        printer(outfile, format, dpi, facecolor, edgecolor,
-                orientation, papertype, **kwargs)
+        printer(outfile, format, dpi=dpi, dsc_comments=dsc_comments,
+                orientation=orientation, papertype=papertype, **kwargs)
 
     @cbook._delete_parameter("3.2", "dryrun")
     def _print_figure(
-            self, outfile, format, dpi, facecolor, edgecolor,
-            orientation, papertype, *,
-            metadata=None, dryrun=False, bbox_inches_restore=None, **kwargs):
+            self, outfile, format, *,
+            dpi, dsc_comments, orientation, papertype,
+            dryrun=False, bbox_inches_restore=None, **kwargs):
         """
-        Render the figure to hardcopy.  Set the figure patch face and
-        edge colors.  This is useful because some of the GUIs have a
-        gray figure face color background and you'll probably want to
-        override this on hardcopy
-
-        If outfile is a string, it is interpreted as a file name.
-        If the extension matches .ep* write encapsulated postscript,
-        otherwise write a stand-alone PostScript file.
-
-        If outfile is a file object, a stand-alone PostScript file is
-        written into this file object.
+        Render the figure to a filesystem path or a file-like object.
 
-        metadata must be a dictionary. Currently, only the value for
-        the key 'Creator' is used.
+        Parameters are as for `.print_figure`, except that *dsc_comments* is a
+        all string containing Document Structuring Convention comments,
+        generated from the *metadata* parameter to `.print_figure`.
         """
         is_eps = format == 'eps'
         if isinstance(outfile, (str, os.PathLike)):
-            outfile = title = os.fspath(outfile)
-            title = title.encode("ascii", "replace").decode("ascii")
+            outfile = os.fspath(outfile)
             passed_in_file_object = False
         elif is_writable_file_like(outfile):
-            title = None
             passed_in_file_object = True
         else:
             raise ValueError("outfile must be a path or a file-like object")
@@ -848,12 +854,6 @@ def _print_figure(
             rotation = 90
         bbox = (llx, lly, urx, ury)
 
-        # generate PostScript code for the figure and store it in a string
-        origfacecolor = self.figure.get_facecolor()
-        origedgecolor = self.figure.get_edgecolor()
-        self.figure.set_facecolor(facecolor)
-        self.figure.set_edgecolor(edgecolor)
-
         if dryrun:
             class NullWriter:
                 def write(self, *args, **kwargs):
@@ -874,16 +874,6 @@ def write(self, *args, **kwargs):
         if dryrun:  # return immediately if dryrun (tightbbox=True)
             return
 
-        self.figure.set_facecolor(origfacecolor)
-        self.figure.set_edgecolor(origedgecolor)
-
-        # check for custom metadata
-        if metadata is not None and 'Creator' in metadata:
-            creator_str = metadata['Creator']
-        else:
-            creator_str = \
-                f"matplotlib version {mpl.__version__}, http://matplotlib.org/"
-
         def print_figure_impl(fh):
             # write the PostScript headers
             if is_eps:
@@ -893,18 +883,7 @@ def print_figure_impl(fh):
                       f"%%DocumentPaperSizes: {papertype}\n"
                       f"%%Pages: 1\n",
                       end="", file=fh)
-            if title:
-                print("%%Title: " + title, file=fh)
-            # get source date from SOURCE_DATE_EPOCH, if set
-            # See https://reproducible-builds.org/specs/source-date-epoch/
-            source_date_epoch = os.getenv("SOURCE_DATE_EPOCH")
-            if source_date_epoch:
-                source_date = datetime.datetime.utcfromtimestamp(
-                    int(source_date_epoch)).strftime("%a %b %d %H:%M:%S %Y")
-            else:
-                source_date = time.ctime()
-            print(f"%%Creator: {creator_str}\n"
-                  f"%%CreationDate: {source_date}\n"
+            print(f"{dsc_comments}\n"
                   f"%%Orientation: {orientation.name}\n"
                   f"%%BoundingBox: {bbox[0]} {bbox[1]} {bbox[2]} {bbox[3]}\n"
                   f"%%EndComments\n",
@@ -1006,28 +985,18 @@ def print_figure_impl(fh):
 
     @cbook._delete_parameter("3.2", "dryrun")
     def _print_figure_tex(
-            self, outfile, format, dpi, facecolor, edgecolor,
-            orientation, papertype, *,
-            metadata=None, dryrun=False, bbox_inches_restore=None, **kwargs):
+            self, outfile, format, *,
+            dpi, dsc_comments, orientation, papertype,
+            dryrun=False, bbox_inches_restore=None, **kwargs):
         """
-        If text.usetex is True in rc, a temporary pair of tex/eps files
+        If :rc:`text.usetex` is True, a temporary pair of tex/eps files
         are created to allow tex to manage the text layout via the PSFrags
         package. These files are processed to yield the final ps or eps file.
 
-        metadata must be a dictionary. Currently, only the value for
-        the key 'Creator' is used.
+        The rest of the behavior is as for `._print_figure`.
         """
         is_eps = format == 'eps'
-        if is_writable_file_like(outfile):
-            title = None
-        else:
-            try:
-                title = os.fspath(outfile)
-            except TypeError:
-                raise ValueError(
-                    "outfile must be a path or a file-like object")
 
-        self.figure.dpi = 72  # ignore the dpi kwarg
         width, height = self.figure.get_size_inches()
         xo = 0
         yo = 0
@@ -1039,12 +1008,6 @@ def _print_figure_tex(
         ury = lly + h
         bbox = (llx, lly, urx, ury)
 
-        # generate PostScript code for the figure and store it in a string
-        origfacecolor = self.figure.get_facecolor()
-        origedgecolor = self.figure.get_edgecolor()
-        self.figure.set_facecolor(facecolor)
-        self.figure.set_edgecolor(edgecolor)
-
         if dryrun:
             class NullWriter:
                 def write(self, *args, **kwargs):
@@ -1065,35 +1028,13 @@ def write(self, *args, **kwargs):
         if dryrun:  # return immediately if dryrun (tightbbox=True)
             return
 
-        self.figure.set_facecolor(origfacecolor)
-        self.figure.set_edgecolor(origedgecolor)
-
-        # check for custom metadata
-        if metadata is not None and 'Creator' in metadata:
-            creator_str = metadata['Creator']
-        else:
-            creator_str = \
-                f"matplotlib version {mpl.__version__}, http://matplotlib.org/"
-
         # write to a temp file, we'll move it to outfile when done
-
         with TemporaryDirectory() as tmpdir:
             tmpfile = os.path.join(tmpdir, "tmp.ps")
-            # get source date from SOURCE_DATE_EPOCH, if set
-            # See https://reproducible-builds.org/specs/source-date-epoch/
-            source_date_epoch = os.getenv("SOURCE_DATE_EPOCH")
-            if source_date_epoch:
-                source_date = datetime.datetime.utcfromtimestamp(
-                    int(source_date_epoch)).strftime("%a %b %d %H:%M:%S %Y")
-            else:
-                source_date = time.ctime()
             pathlib.Path(tmpfile).write_text(
                 f"""\
 %!PS-Adobe-3.0 EPSF-3.0
-{f'''%%Title: {title}
-''' if title else ""}\
-%%Creator: {creator_str}
-%%CreationDate: {source_date}
+{dsc_comments}
 %%BoundingBox: {bbox[0]} {bbox[1]} {bbox[2]} {bbox[3]}
 %%EndComments
 %%BeginProlog
@@ -1122,12 +1063,9 @@ def write(self, *args, **kwargs):
                 paper_width, paper_height = orientation.swap_if_landscape(
                     self.figure.get_size_inches())
             else:
-                temp_papertype = _get_papertype(width, height)
                 if papertype == 'auto':
-                    papertype = temp_papertype
-                    paper_width, paper_height = papersize[temp_papertype]
-                else:
-                    paper_width, paper_height = papersize[papertype]
+                    papertype = _get_papertype(width, height)
+                paper_width, paper_height = papersize[papertype]
 
             texmanager = ps_renderer.get_texmanager()
             font_preamble = texmanager.get_font_preamble()
