improve integral and slanted nuclei placement

zblz · zblz · commit 2959e579358b · 2015-08-08T21:11:24.000+01:00
diff --git a/lib/matplotlib/mathtext.py b/lib/matplotlib/mathtext.py
@@ -1187,15 +1187,15 @@ def get_underline_thickness(self, font, fontsize, dpi):
 # get any smaller
 NUM_SIZE_LEVELS = 6
 # Percentage of x-height of additional horiz. space after sub/superscripts
-SCRIPT_SPACE    = {'cm': 0.025,
-                   'stix': 0.20,
+SCRIPT_SPACE    = {'cm': 0.05,
+                   'stix': 0.10,
                    'stixsans': 0.10,
-                   'arevsans': 0.10}
+                   'arevsans': 0.05}
 ## Percentage of x-height that sub/superscripts drop below the baseline
-SUBDROP         = {'cm': 0.3,
+SUBDROP         = {'cm': 0.2,
                    'stix': 0.4,
                    'stixsans': 0.4,
-                   'arevsans': 0.3}
+                   'arevsans': 0.4}
 # Percentage of x-height that superscripts are raised from the baseline
 SUP1            = {'cm': 0.45,
                    'stix': 0.8,
@@ -1211,25 +1211,25 @@ def get_underline_thickness(self, font, fontsize, dpi):
 SUB2            = {'cm': 0.3,
                    'stix': 0.6,
                    'stixsans': 0.5,
-                   'arevsans': 0.8}
+                   'arevsans': 0.5}
 # Percentage of x-height that sub/supercripts are offset relative to the
-# nucleus end
-DELTA           = {'cm': 0.10,
-                   'stix': 0.10,
-                   'stixsans': 0.25,
-                   'arevsans': 0.12}
-# Additional percentage of last character height that supercripts are offset
-# relative to the subscript for slanted nuclei
-DELTASLANTED    = {'cm': 0.05,
+# nucleus edge
+DELTA           = {'cm': 0.025,
                    'stix': 0.05,
                    'stixsans': 0.05,
-                   'arevsans': 0.12}
-# Percentage of x-height that supercripts are offset relative to the subscript
-# for integrals
-DELTAINTEGRAL   = {'cm': 0.5,
-                   'stix': 0.5,
-                   'stixsans': 0.4,
-                   'arevsans': 0.5}
+                   'arevsans': 0.05}
+# Additional percentage of last character height above 2/3 of the x-height that
+# supercripts are offset relative to the subscript for slanted nuclei
+DELTASLANTED    = {'cm': 0.4,
+                   'stix': 0.3,
+                   'stixsans': 0.5,
+                   'arevsans': 0.2}
+# Percentage of x-height that supercripts and subscripts are offset for
+# integrals
+DELTAINTEGRAL   = {'cm': 0.325,
+                   'stix': 0.3,
+                   'stixsans': 0.3,
+                   'arevsans': 0.3}
 
 class MathTextWarning(Warning):
     pass
@@ -2718,24 +2718,35 @@ def subsuper(self, s, loc, toks):
                 "Subscript/superscript sequence is too long. "
                 "Use braces { } to remove ambiguity.")
 
+        # We remove kerning for consistency (otherwise it will compute kerning
+        # based on non-shrinked characters and may put them very close together
+        # when superscripted)
+        # We change the width of the last character to match the advance to
+        # consider some fonts with weird metrics: e.g. stix's f has a width of
+        # 7.75 and a kerning of -4.0 for an advance of 3.72, and we want to put
+        # the superscript at the advance
         last_char = nucleus
         if isinstance(nucleus,Hlist):
-            # remove kerns
-            new_children = []
-            for child in nucleus.children:
-                if not isinstance(child, Kern):
-                    new_children.append(child)
-            nucleus = Hlist(new_children, do_kern=False)
+            new_children = nucleus.children
             if len(new_children):
+                # remove last kern
+                if isinstance(new_children[-1],Kern):
+                    new_children = new_children[:-1]
                 last_char = new_children[-1]
+                last_char.width = last_char._metrics.advance
+            nucleus = Hlist(new_children, do_kern=False)
         else:
+            last_char.width = last_char._metrics.advance
             nucleus = Hlist([nucleus],do_kern=False)
 
+
         state = self.get_state()
         rule_thickness = state.font_output.get_underline_thickness(
             state.font, state.fontsize, state.dpi)
         xHeight = state.font_output.get_xheight(
             state.font, state.fontsize, state.dpi)
+        print(last_char, last_char.height, 
+                xHeight)
 
         fs = rcParams['mathtext.fontset']
         # If a custom fontset is used, check if it is Arev Sans, otherwise use
@@ -2747,6 +2758,7 @@ def subsuper(self, s, loc, toks):
             else:
                 fs = 'cm'
 
+
         if napostrophes:
             if super is None:
                 super = Hlist([])
@@ -2792,11 +2804,13 @@ def subsuper(self, s, loc, toks):
         superkern = DELTA[fs] * xHeight
         subkern = DELTA[fs] * xHeight
         if self.is_slanted(last_char):
-            superkern += DELTASLANTED[fs] * xHeight
+            superkern += DELTASLANTED[fs] * (lc_height - xHeight * 2. / 3.)
             if self.is_dropsub(last_char):
-                subkern = -DELTAINTEGRAL[fs] * lc_height
+                subkern = (2 * DELTA[fs] - DELTAINTEGRAL[fs]) * lc_height
+                superkern = (2 * DELTA[fs] + DELTAINTEGRAL[fs]) * lc_height
             else:
-                subkern = 0.25 * DELTA[fs] * lc_height
+                subkern = -DELTA[fs] * xHeight
+        #subkern, superkern =0,0
 
         if super is None:
             # node757
@@ -2833,7 +2847,8 @@ def subsuper(self, s, loc, toks):
                            y])
                 x.shift_amount = shift_down
 
-        x.width += SCRIPT_SPACE[fs] * xHeight
+        if not self.is_dropsub(last_char):
+            x.width += SCRIPT_SPACE[fs] * xHeight
         result = Hlist([nucleus, x], do_kern=False)
         return [result]
 
