font-patcher: Do not maximize heavy brackets in Mono

[why]
The added heavy brackets are maximized within the cell size as all
normal other symbols. But in fact they should not be maximized but
rather be the size of 'normal brackets'.

Furthermore they are all scaled individually, making the size
differences less.

[how]
Introduce new y-padding parameter (because a negative overlap also acts
in x direction, what we do not want.

Pad the brackets with 30% (15% top and 15% bottom).

This has only effect in Nerd Font Mono fonts.

Fixes: #1229

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

font-patcher

@@ -803,7 +803,7 @@ class font_patcher:
                 box_enabled = False # Cowardly not scaling existing glyphs, although the code would allow this
 
         # Stretch 'xz' or 'pa' (preserve aspect ratio)
-        # Supported params: overlap | careful | xy-ratio | dont_copy
+        # Supported params: overlap | careful | xy-ratio | dont_copy | ypadding
         # Overlap value is used horizontally but vertically limited to 0.01
         # Careful does not overwrite/modify existing glyphs
         # The xy-ratio limits the x-scale for a given y-scale to make the ratio <= this value (to prevent over-wide glyphs)
@@ -887,7 +887,7 @@ class font_patcher:
             0xf0de: {'align': 'c', 'valign': '', 'stretch': 'pa', 'params': {}}
         }
         SYM_ATTR_HEAVYBRACKETS = {
-            'default': {'align': 'c', 'valign': 'c', 'stretch': 'pa', 'params': {'careful': True}}
+            'default': {'align': 'c', 'valign': 'c', 'stretch': 'pa', 'params': {'careful': True, 'ypadding': 0.15}}
         }
         SYM_ATTR_BOX = {
             'default': {'align': 'c', 'valign': 'c', 'stretch': 'xy', 'params': {'overlap': 0.02, 'dont_copy': box_keep}},
@@ -984,6 +984,10 @@ class font_patcher:
             range(0xf221, 0xf22d + 1), # gender or so
             range(0xf255, 0xf25b + 1), # hand symbols
         ]}
+        HEAVY_SCALE_LIST = {'ScaleGlyph': 0x2771, # widest bracket, horizontally
+            'GlyphsToScale': [
+                (0x276c, 0x2771) # all
+        ]}
         OCTI_SCALE_LIST = {'ScaleGroups': [
                 [*range(0xf03d, 0xf040 + 1), 0xf019, 0xf030, 0xf04a, 0xf050,  0xf071, 0xf08c ], # arrows
                 [0xF0E7, # Smily and ...
@@ -1021,7 +1025,7 @@ class font_patcher:
         # Symbol font ranges
         self.patch_set = [
             {'Enabled': True,                           'Name': "Seti-UI + Custom",        'Filename': "original-source.otf",                            'Exact': False, 'SymStart': 0xE4FA, 'SymEnd': 0xE5FF, 'SrcStart': 0xE5FA, 'ScaleRules': None,             'Attributes': SYM_ATTR_DEFAULT},
-            {'Enabled': True,                           'Name': "Heavy Angle Brackets",    'Filename': "extraglyphs.sfd",                                'Exact': True,  'SymStart': 0x276C, 'SymEnd': 0x2771, 'SrcStart': None,   'ScaleRules': None,             'Attributes': SYM_ATTR_HEAVYBRACKETS},
+            {'Enabled': True,                           'Name': "Heavy Angle Brackets",    'Filename': "extraglyphs.sfd",                                'Exact': True,  'SymStart': 0x276C, 'SymEnd': 0x2771, 'SrcStart': None,   'ScaleRules': HEAVY_SCALE_LIST, 'Attributes': SYM_ATTR_HEAVYBRACKETS},
             {'Enabled': box_enabled,                    'Name': "Box Drawing",             'Filename': "extraglyphs.sfd",                                'Exact': True,  'SymStart': 0x2500, 'SymEnd': 0x259F, 'SrcStart': None,   'ScaleRules': BOX_SCALE_LIST,   'Attributes': SYM_ATTR_BOX},
             {'Enabled': True,                           'Name': "Devicons",                'Filename': "devicons.ttf",                                   'Exact': False, 'SymStart': 0xE600, 'SymEnd': 0xE6C5, 'SrcStart': 0xE700, 'ScaleRules': DEVI_SCALE_LIST,  'Attributes': SYM_ATTR_DEFAULT},
             {'Enabled': self.args.powerline,            'Name': "Powerline Symbols",       'Filename': "powerline-symbols/PowerlineSymbols.otf",         'Exact': True,  'SymStart': 0xE0A0, 'SymEnd': 0xE0A2, 'SrcStart': None,   'ScaleRules': None,             'Attributes': SYM_ATTR_POWERLINE},
@@ -1387,9 +1391,16 @@ class font_patcher:
                 (scale_ratio_x, scale_ratio_y) = self.get_scale_factors(sym_dim, sym_attr['stretch'])
 
             overlap = sym_attr['params'].get('overlap')
+            padding = sym_attr['params'].get('ypadding')
+            if overlap and padding:
+                logger.critical("Conflicting params: overlap and ypadding")
+                sys.exit(1)
             if overlap:
                 scale_ratio_x *= 1.0 + (self.font_dim['width'] / (sym_dim['width'] * scale_ratio_x)) * overlap
                 y_overlap = min(0.01, overlap) # never aggressive vertical overlap
+            else:
+                y_overlap = -padding if padding else None
+            if y_overlap:
                 scale_ratio_y *= 1.0 + (self.font_dim['height'] / (sym_dim['height'] * scale_ratio_y)) * y_overlap
 
             # Size in x to size in y ratio limit (to prevent over-wide glyphs)