Factor out common code between pdf and ps backends.

anntzer · anntzer · commit b6a2f4adb255 · 2019-01-04T18:32:16.000+01:00
(The AFM cache only needs to cache on filename, not on font properties,
because the fontprop-&gt;filename conversion is already cached by
font_manager.)
diff --git a/doc/api/next_api_changes/2018-10-05-AL-deprecations.rst b/doc/api/next_api_changes/2018-10-05-AL-deprecations.rst
@@ -0,0 +1,7 @@
+API deprecations
+````````````````
+
+The following API elements are deprecated:
+
+- ``backend_pdf.RendererPdf.afm_font_cache``,
+- ``backend_ps.RendererPS.afmfontd``,
diff --git a/lib/matplotlib/backends/_backend_pdf_ps.py b/lib/matplotlib/backends/_backend_pdf_ps.py
@@ -0,0 +1,79 @@
+"""
+Common functionality between the PDF and PS backends.
+"""
+
+import functools
+
+from .. import font_manager, ft2font, rcParams
+from ..afm import AFM
+from ..backend_bases import RendererBase
+
+
+@functools.lru_cache(50)
+def _cached_get_afm_from_fname(fname):
+    with open(fname, 'rb') as fh:
+        return AFM(fh)
+
+
+class RendererPDFPSBase(RendererBase):
+    # The following attributes must be defined by the subclasses:
+    # - _afm_font_dir
+    # - _use_afm_rc_name
+
+    def flipy(self):
+        # docstring inherited
+        return False  # y increases from bottom to top.
+
+    def option_scale_image(self):
+        # docstring inherited
+        return True  # PDF and PS support arbitrary image scaling.
+
+    def option_image_nocomposite(self):
+        # docstring inherited
+        # Decide whether to composite image based on rcParam value.
+        return not rcParams['image.composite_image']
+
+    def get_text_width_height_descent(self, s, prop, ismath):
+        # docstring inherited
+        if rcParams['text.usetex']:
+            texmanager = self.get_texmanager()
+            fontsize = prop.get_size_in_points()
+            w, h, d = texmanager.get_text_width_height_descent(
+                s, fontsize, renderer=self)
+            return w, h, d
+        elif ismath:
+            parse = self.mathtext_parser.parse(s, 72, prop)
+            return parse.width, parse.height, parse.depth
+        elif rcParams[self._use_afm_rc_name]:
+            font = self._get_font_afm(prop)
+            l, b, w, h, d = font.get_str_bbox_and_descent(s)
+            scale = prop.get_size_in_points() / 1000
+            w *= scale
+            h *= scale
+            d *= scale
+            return w, h, d
+        else:
+            font = self._get_font_ttf(prop)
+            font.set_text(s, 0.0, flags=ft2font.LOAD_NO_HINTING)
+            w, h = font.get_width_height()
+            d = font.get_descent()
+            scale = 1 / 64
+            w *= scale
+            h *= scale
+            d *= scale
+            return w, h, d
+
+    def _get_font_afm(self, prop):
+        fname = (
+            font_manager.findfont(
+                prop, fontext='afm', directory=self._afm_font_dir)
+            or font_manager.findfont(
+                "Helvetica", fontext='afm', directory=self._afm_font_dir))
+        return _cached_get_afm_from_fname(fname)
+
+    def _get_font_ttf(self, prop):
+        fname = font_manager.findfont(prop)
+        font = font_manager.get_font(fname)
+        font.clear()
+        font.set_size(prop.get_size_in_points(), 72)
+        return font
diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
@@ -26,7 +26,6 @@
     _Backend, FigureCanvasBase, FigureManagerBase, GraphicsContextBase,
     RendererBase)
 from matplotlib.backends.backend_mixed import MixedModeRenderer
-from matplotlib.cbook import get_realpath_and_stat, maxdict
 from matplotlib.figure import Figure
 from matplotlib.font_manager import findfont, is_opentype_cff_font, get_font
 from matplotlib.afm import AFM
@@ -41,6 +40,7 @@
 from matplotlib import _path
 from matplotlib import _png
 from matplotlib import ttconv
+from . import _backend_pdf_ps
 
 _log = logging.getLogger(__name__)
 
@@ -706,7 +706,7 @@ def writeFonts(self):
             else:
                 # a normal TrueType font
                 _log.debug('Writing TrueType font.')
-                realpath, stat_key = get_realpath_and_stat(filename)
+                realpath, stat_key = cbook.get_realpath_and_stat(filename)
                 chars = self.used_characters.get(stat_key)
                 if chars is not None and len(chars[1]):
                     fonts[Fx] = self.embedTTF(realpath, chars[1])
@@ -1574,8 +1574,14 @@ def writeTrailer(self):
         self.write(b"\nstartxref\n%d\n%%%%EOF\n" % self.startxref)
 
 
-class RendererPdf(RendererBase):
-    afm_font_cache = maxdict(50)
+class RendererPdf(_backend_pdf_ps.RendererPDFPSBase):
+    @property
+    @cbook.deprecated("3.1")
+    def afm_font_cache(self, _cache=cbook.maxdict(50)):
+        return _cache
+
+    _afm_font_dir = os.path.join(rcParams['datapath'], 'fonts', 'pdfcorefonts')
+    _use_afm_rc_name = "pdf.use14corefonts"
 
     def __init__(self, file, image_dpi, height, width):
         RendererBase.__init__(self)
@@ -1623,7 +1629,7 @@ def track_characters(self, font, s):
             fname = font
         else:
             fname = font.fname
-        realpath, stat_key = get_realpath_and_stat(fname)
+        realpath, stat_key = cbook.get_realpath_and_stat(fname)
         used_characters = self.file.used_characters.setdefault(
             stat_key, (realpath, set()))
         used_characters[1].update(map(ord, s))
@@ -1637,14 +1643,6 @@ def merge_used_characters(self, other):
     def get_image_magnification(self):
         return self.image_dpi/72.0
 
-    def option_scale_image(self):
-        # docstring inherited
-        return True
-
-    def option_image_nocomposite(self):
-        # docstring inherited
-        return not rcParams['image.composite_image']
-
     def draw_image(self, gc, x, y, im, transform=None):
         # docstring inherited
 
@@ -2120,67 +2118,6 @@ def draw_text_woven(chunks):
         else:
             return draw_text_woven(chunks)
 
-    def get_text_width_height_descent(self, s, prop, ismath):
-        # docstring inherited
-
-        if rcParams['text.usetex']:
-            texmanager = self.get_texmanager()
-            fontsize = prop.get_size_in_points()
-            w, h, d = texmanager.get_text_width_height_descent(s, fontsize,
-                                                               renderer=self)
-            return w, h, d
-
-        if ismath:
-            w, h, d, glyphs, rects, used_characters = \
-                self.mathtext_parser.parse(s, 72, prop)
-
-        elif rcParams['pdf.use14corefonts']:
-            font = self._get_font_afm(prop)
-            l, b, w, h, d = font.get_str_bbox_and_descent(s)
-            scale = prop.get_size_in_points()
-            w *= scale / 1000
-            h *= scale / 1000
-            d *= scale / 1000
-        else:
-            font = self._get_font_ttf(prop)
-            font.set_text(s, 0.0, flags=LOAD_NO_HINTING)
-            w, h = font.get_width_height()
-            scale = (1.0 / 64.0)
-            w *= scale
-            h *= scale
-            d = font.get_descent()
-            d *= scale
-        return w, h, d
-
-    def _get_font_afm(self, prop):
-        key = hash(prop)
-        font = self.afm_font_cache.get(key)
-        if font is None:
-            filename = findfont(
-                prop, fontext='afm', directory=self.file._core14fontdir)
-            if filename is None:
-                filename = findfont(
-                    "Helvetica", fontext='afm',
-                    directory=self.file._core14fontdir)
-            font = self.afm_font_cache.get(filename)
-            if font is None:
-                with open(filename, 'rb') as fh:
-                    font = AFM(fh)
-                    self.afm_font_cache[filename] = font
-            self.afm_font_cache[key] = font
-        return font
-
-    def _get_font_ttf(self, prop):
-        filename = findfont(prop)
-        font = get_font(filename)
-        font.clear()
-        font.set_size(prop.get_size_in_points(), 72)
-        return font
-
-    def flipy(self):
-        # docstring inherited
-        return False
-
     def get_canvas_width_height(self):
         # docstring inherited
         return self.file.width * 72.0, self.file.height * 72.0
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
@@ -17,22 +17,22 @@
 
 import numpy as np
 
-from matplotlib import cbook, __version__, rcParams, checkdep_ghostscript
-from matplotlib.afm import AFM
+from matplotlib import (
+    cbook, _path, __version__, rcParams, checkdep_ghostscript)
 from matplotlib.backend_bases import (
     _Backend, FigureCanvasBase, FigureManagerBase, GraphicsContextBase,
     RendererBase)
 from matplotlib.cbook import (get_realpath_and_stat, is_writable_file_like,
-                              maxdict, file_requires_unicode)
-from matplotlib.font_manager import findfont, is_opentype_cff_font, get_font
+                              file_requires_unicode)
+from matplotlib.font_manager import is_opentype_cff_font, get_font
 from matplotlib.ft2font import KERNING_DEFAULT, LOAD_NO_HINTING
 from matplotlib.ttconv import convert_ttf_to_ps
 from matplotlib.mathtext import MathTextParser
 from matplotlib._mathtext_data import uni2type1
 from matplotlib.path import Path
-from matplotlib import _path
 from matplotlib.transforms import Affine2D
 from matplotlib.backends.backend_mixed import MixedModeRenderer
+from . import _backend_pdf_ps
 
 _log = logging.getLogger(__name__)
 
@@ -180,13 +180,19 @@ def _move_path_to_path_or_stream(src, dst):
         shutil.move(src, dst, copy_function=shutil.copyfile)
 
 
-class RendererPS(RendererBase):
+class RendererPS(_backend_pdf_ps.RendererPDFPSBase):
     """
     The renderer handles all the drawing primitives using a graphics
     context instance that controls the colors/styles.
     """
 
-    afmfontd = maxdict(50)
+    @property
+    @cbook.deprecated("3.1")
+    def afmfontd(self, _cache=cbook.maxdict(50)):
+        return _cache
+
+    _afm_font_dir = os.path.join(rcParams['datapath'], 'fonts', 'afm')
+    _use_afm_rc_name = "ps.useafm"
 
     def __init__(self, width, height, pswriter, imagedpi=72):
         # Although postscript itself is dpi independent, we need to imform the
@@ -217,9 +223,6 @@ def __init__(self, width, height, pswriter, imagedpi=72):
         self.used_characters = {}
         self.mathtext_parser = MathTextParser("PS")
 
-        self._afm_font_dir = os.path.join(
-            rcParams['datapath'], 'fonts', 'afm')
-
     def track_characters(self, font, s):
         """Keeps track of which characters are required from each font."""
         realpath, stat_key = get_realpath_and_stat(font.fname)
@@ -327,71 +330,6 @@ def get_canvas_width_height(self):
         # docstring inherited
         return self.width * 72.0, self.height * 72.0
 
-    def get_text_width_height_descent(self, s, prop, ismath):
-        # docstring inherited
-
-        if rcParams['text.usetex']:
-            texmanager = self.get_texmanager()
-            fontsize = prop.get_size_in_points()
-            w, h, d = texmanager.get_text_width_height_descent(s, fontsize,
-                                                               renderer=self)
-            return w, h, d
-
-        if ismath:
-            width, height, descent, pswriter, used_characters = \
-                self.mathtext_parser.parse(s, 72, prop)
-            return width, height, descent
-
-        if rcParams['ps.useafm']:
-            if ismath:
-                s = s[1:-1]
-            font = self._get_font_afm(prop)
-            l, b, w, h, d = font.get_str_bbox_and_descent(s)
-
-            fontsize = prop.get_size_in_points()
-            scale = 0.001 * fontsize
-            w *= scale
-            h *= scale
-            d *= scale
-            return w, h, d
-
-        font = self._get_font_ttf(prop)
-        font.set_text(s, 0.0, flags=LOAD_NO_HINTING)
-        w, h = font.get_width_height()
-        w /= 64  # convert from subpixels
-        h /= 64
-        d = font.get_descent()
-        d /= 64
-        return w, h, d
-
-    def flipy(self):
-        # docstring inherited
-        return False
-
-    def _get_font_afm(self, prop):
-        key = hash(prop)
-        font = self.afmfontd.get(key)
-        if font is None:
-            fname = findfont(prop, fontext='afm', directory=self._afm_font_dir)
-            if fname is None:
-                fname = findfont(
-                    "Helvetica", fontext='afm', directory=self._afm_font_dir)
-            font = self.afmfontd.get(fname)
-            if font is None:
-                with open(fname, 'rb') as fh:
-                    font = AFM(fh)
-                self.afmfontd[fname] = font
-            self.afmfontd[key] = font
-        return font
-
-    def _get_font_ttf(self, prop):
-        fname = findfont(prop)
-        font = get_font(fname)
-        font.clear()
-        size = prop.get_size_in_points()
-        font.set_size(size, 72.0)
-        return font
-
     def _rgb(self, rgba):
         h, w = rgba.shape[:2]
         rgb = rgba[::-1, :, :3]
@@ -414,14 +352,6 @@ def get_image_magnification(self):
         """
         return self.image_magnification
 
-    def option_scale_image(self):
-        # docstring inherited
-        return True
-
-    def option_image_nocomposite(self):
-        # docstring inherited
-        return not rcParams['image.composite_image']
-
     def _get_image_h_w_bits_command(self, im):
         h, w, bits = self._rgb(im)
         imagecmd = "false 3 colorimage"
diff --git a/lib/matplotlib/mathtext.py b/lib/matplotlib/mathtext.py
