Refactor segment rendering

This commit introduces the following changes to themes and segment
rendering:

- Spacer segments are now regular string/function type segments with
  "width": "auto" in the themes.
- The "rjust"/"ljust" properties have been replaced by the "width"
  option combined with a new "align" option.
- Renderer._render_segments() is now a generator which renders each
  segment separately, and assigns the rendered contents to
  "_rendered_hl" and "_rendered_raw" in the segment dict.
- Renderer.render() returns the segments by joining the "_rendered_hl"
  values for each segment.
- Spacer segment widths are calculated in the render() method, and
  assigned to "_space_left" and "_space_right" in the segment dict.
  These spaces are then applied in Renderer._render_segments().
- All space characters are converted to no-break spaces (U+00A0) in the
  "_rendered_hl" property.

Refs Lokaltog#113.
Refs #154.

docs/source/configuration.rst

@@ -237,12 +237,6 @@ Themes
             highlighting group is defined in the :ref:`highlight_group 
             option <config-themes-seg-highlight_group>`.
 
-        ``filler``
-            If the statusline is rendered with a specific width, remaining 
-            whitespace is distributed among filler segments. The 
-            highlighting group is defined in the :ref:`highlight_group 
-            option <config-themes-seg-highlight_group>`.
-
     ``module``
         .. _config-themes-seg-module:
 
@@ -276,13 +270,18 @@ Themes
     ``args``
         A dict of arguments to be passed to a ``function`` segment.
 
-    ``ljust``
-        If set, the segment will be left justified to the width specified by 
-        this option.
+    ``align``
+        Aligns the segments contents to the left (``l``), center (``c``) or 
+        right (``r``).
+
+    ``width``
+        Enforces a specific width for this segment.
 
-    ``rjust``
-        If set, the segment will be right justified to the width specified 
-        by this option.
+        This segment will work as a spacer if the width is set to ``auto``.
+        Several spacers may be used, and the space will be distributed 
+        equally among all the spacer segments. Spacers may have contents, 
+        either returned by a function or a static string, and the contents 
+        can be aligned with the ``align`` property.
 
     ``priority``
         Optional segment priority. Segments with priority ``-1`` (the 

powerline/config_files/themes/vim/cmdwin.json

@@ -7,8 +7,10 @@
 				"highlight_group": ["file_name"]
 			},
 			{
-				"type": "filler",
-				"highlight_group": ["background"]
+				"type": "string",
+				"highlight_group": ["background"],
+				"draw_divider": false,
+				"width": "auto"
 			}
 		]
 	}

powerline/config_files/themes/vim/default.json

@@ -41,8 +41,10 @@
 				"before": " "
 			},
 			{
-				"type": "filler",
-				"highlight_group": ["background"]
+				"type": "string",
+				"highlight_group": ["background"],
+				"draw_divider": false,
+				"width": "auto"
 			}
 		],
 		"right": [
@@ -70,7 +72,8 @@
 				"args": { "gradient": true },
 				"priority": 30,
 				"after": "%",
-				"rjust": 4
+				"width": 4,
+				"align": "r"
 			},
 			{
 				"type": "string",
@@ -80,14 +83,16 @@
 			{
 				"name": "line_current",
 				"draw_divider": false,
-				"rjust": 3
+				"width": 3,
+				"align": "r"
 			},
 			{
 				"name": "col_current",
 				"draw_divider": false,
 				"priority": 30,
 				"before": ":",
-				"ljust": 3
+				"width": 3,
+				"align": "l"
 			}
 		]
 	}

powerline/config_files/themes/vim/help.json

@@ -6,8 +6,10 @@
 				"draw_divider": false
 			},
 			{
-				"type": "filler",
-				"highlight_group": ["background"]
+				"type": "string",
+				"highlight_group": ["background"],
+				"draw_divider": false,
+				"width": "auto"
 			}
 		],
 		"right": [
@@ -16,7 +18,8 @@
 				"args": { "gradient": true },
 				"priority": 30,
 				"after": "%",
-				"rjust": 4
+				"width": 4,
+				"align": "r"
 			},
 			{
 				"type": "string",
@@ -26,7 +29,8 @@
 			{
 				"name": "line_current",
 				"draw_divider": false,
-				"rjust": 3
+				"width": 3,
+				"align": "r"
 			}
 		]
 	}

powerline/renderer.py

@@ -11,8 +11,6 @@ class Renderer(object):
 
 	TERM_24BIT_COLORS = False
 
-	PADDING_CHAR = u'\u00a0'  # No-break space
-
 	def __init__(self, theme_config, local_themes, theme_kwargs, term_24bit_colors=False):
 		self.theme = Theme(theme_config=theme_config, **theme_kwargs)
 		self.local_themes = local_themes
@@ -34,13 +32,6 @@ def get_theme(self):
 		else:
 			return self.theme
 
-	@staticmethod
-	def _returned_value(rendered_highlighted, segments, output_raw):
-		if output_raw:
-			return rendered_highlighted, ''.join((segment['rendered_raw'] for segment in segments))
-		else:
-			return rendered_highlighted
-
 	def render(self, mode=None, width=None, theme=None, segments=None, side=None, output_raw=False):
 		'''Render all segments.
 
@@ -56,31 +47,37 @@ def render(self, mode=None, width=None, theme=None, segments=None, side=None, ou
 		# Handle excluded/included segments for the current mode
 		segments = [segment for segment in segments\
 			if mode not in segment['exclude_modes'] or (segment['include_modes'] and segment in segment['include_modes'])]
-		rendered_highlighted = self._render_segments(mode, theme, segments)
+
+		segments = [segment for segment in self._render_segments(mode, theme, segments)]
+
 		if not width:
 			# No width specified, so we don't need to crop or pad anything
-			return self._returned_value(rendered_highlighted, segments, output_raw)
+			return self._returned_value(u''.join([segment['_rendered_hl'] for segment in segments]) + self.hl(), segments, output_raw)
 
 		# Create an ordered list of segments that can be dropped
 		segments_priority = [segment for segment in sorted(segments, key=lambda segment: segment['priority'], reverse=True) if segment['priority'] > 0]
-		while self._total_len(segments) > width and len(segments_priority):
+		while sum([segment['_len'] for segment in segments]) > width and len(segments_priority):
 			segments.remove(segments_priority[0])
 			segments_priority.pop(0)
 
-		# Do another render pass so we can calculate the correct amount of filler space
-		self._render_segments(mode, theme, segments, render_highlighted=False)
-
-		# Distribute the remaining space on the filler segments
-		segments_fillers = [segment for segment in segments if segment['type'] == 'filler']
-		if segments_fillers:
-			segments_fillers_len, segments_fillers_remainder = divmod((width - self._total_len(segments)), len(segments_fillers))
-			segments_fillers_contents = self.PADDING_CHAR * segments_fillers_len
-			for segment in segments_fillers:
-				segment['contents'] = segments_fillers_contents
-			# Add remainder whitespace to the first filler segment
-			segments_fillers[0]['contents'] += self.PADDING_CHAR * segments_fillers_remainder
-
-		return self._returned_value(self._render_segments(mode, theme, segments), segments, output_raw)
+		# Distribute the remaining space on spacer segments
+		segments_spacers = [segment for segment in segments if segment['width'] == 'auto']
+		if segments_spacers:
+			distribute_len, distribute_len_remainder = divmod(width - sum([segment['_len'] for segment in segments]), len(segments_spacers))
+			for segment in segments_spacers:
+				if segment['align'] == 'l':
+					segment['_space_right'] += distribute_len
+				elif segment['align'] == 'r':
+					segment['_space_left'] += distribute_len
+				elif segment['align'] == 'c':
+					space_side, space_side_remainder = divmod(distribute_len, 2)
+					segment['_space_left'] += space_side + space_side_remainder
+					segment['_space_right'] += space_side
+			segments_spacers[0]['_space_right'] += distribute_len_remainder
+
+		rendered_highlighted = u''.join([segment['_rendered_hl'] for segment in self._render_segments(mode, theme, segments)]) + self.hl()
+
+		return self._returned_value(rendered_highlighted, segments, output_raw)
 
 	def _render_segments(self, mode, theme, segments, render_highlighted=True):
 		'''Internal segment rendering method.
@@ -93,19 +90,20 @@ def _render_segments(self, mode, theme, segments, render_highlighted=True):
 		highlighting strings added), and only renders the highlighted
 		statusline if render_highlighted is True.
 		'''
-		rendered_highlighted = u''
 		segments_len = len(segments)
 		try:
 			mode = mode if mode in segments[0]['highlight'] else Colorscheme.DEFAULT_MODE_KEY
 		except IndexError:
-			return ''
+			pass
 
 		for index, segment in enumerate(segments):
+			segment['_rendered_raw'] = u''
+			segment['_rendered_hl'] = u''
+
 			prev_segment = segments[index - 1] if index > 0 else theme.EMPTY_SEGMENT
 			next_segment = segments[index + 1] if index < segments_len - 1 else theme.EMPTY_SEGMENT
 			compare_segment = next_segment if segment['side'] == 'left' else prev_segment
-			segment['rendered_raw'] = u''
-			outer_padding = self.PADDING_CHAR if (index == 0 and segment['side'] == 'left') or (index == segments_len - 1 and segment['side'] == 'right') else ''
+			outer_padding = ' ' if (index == 0 and segment['side'] == 'left') or (index == segments_len - 1 and segment['side'] == 'right') else ''
 			divider_type = 'soft' if compare_segment['highlight'][mode]['bg'] == segment['highlight'][mode]['bg'] else 'hard'
 
 			divider_raw = theme.get_divider(segment['side'], divider_type)
@@ -114,22 +112,18 @@ def _render_segments(self, mode, theme, segments, render_highlighted=True):
 			contents_highlighted = ''
 
 			# Pad segments first
-			if segment['type'] == 'filler':
-				pass
-			elif segment['draw_divider'] or divider_type == 'hard':
+			if segment['draw_divider'] or (divider_type == 'hard' and segment['width'] != 'auto'):
 				if segment['side'] == 'left':
-					contents_raw = outer_padding + contents_raw + self.PADDING_CHAR
-					divider_raw = divider_raw + self.PADDING_CHAR
+					contents_raw = outer_padding + (segment['_space_left'] * ' ') + contents_raw + (segment['_space_right'] * ' ') + ' '
+					divider_raw = divider_raw + ' '
 				else:
-					contents_raw = self.PADDING_CHAR + contents_raw + outer_padding
-					divider_raw = self.PADDING_CHAR + divider_raw
-			elif contents_raw:
+					contents_raw = ' ' + (segment['_space_left'] * ' ') + contents_raw + (segment['_space_right'] * ' ') + outer_padding
+					divider_raw = ' ' + divider_raw
+			else:
 				if segment['side'] == 'left':
-					contents_raw = outer_padding + contents_raw
+					contents_raw = outer_padding + (segment['_space_left'] * ' ') + contents_raw + (segment['_space_right'] * ' ')
 				else:
-					contents_raw = contents_raw + outer_padding
-			else:
-				raise ValueError('Unknown segment type')
+					contents_raw = (segment['_space_left'] * ' ') + contents_raw + (segment['_space_right'] * ' ') + outer_padding
 
 			# Apply highlighting to padded dividers and contents
 			if render_highlighted:
@@ -144,37 +138,31 @@ def _render_segments(self, mode, theme, segments, render_highlighted=True):
 				contents_highlighted = self.hl(self.escape(contents_raw), **segment['highlight'][mode])
 
 			# Append padded raw and highlighted segments to the rendered segment variables
-			if segment['type'] == 'filler':
-				rendered_highlighted += contents_highlighted if contents_raw else ''
-			elif segment['draw_divider'] or divider_type == 'hard':
-				# Draw divider if specified, or if it's a hard divider
-				# Note: Hard dividers are always drawn, regardless of
-				# the draw_divider option
+			if segment['draw_divider'] or (divider_type == 'hard' and segment['width'] != 'auto'):
 				if segment['side'] == 'left':
-					segment['rendered_raw'] += contents_raw + divider_raw
-					rendered_highlighted += contents_highlighted + divider_highlighted
+					segment['_rendered_raw'] += contents_raw + divider_raw
+					segment['_rendered_hl'] += contents_highlighted + divider_highlighted
 				else:
-					segment['rendered_raw'] += divider_raw + contents_raw
-					rendered_highlighted += divider_highlighted + contents_highlighted
-			elif contents_raw:
-				# Segments without divider
+					segment['_rendered_raw'] += divider_raw + contents_raw
+					segment['_rendered_hl'] += divider_highlighted + contents_highlighted
+			else:
 				if segment['side'] == 'left':
-					segment['rendered_raw'] += contents_raw
-					rendered_highlighted += contents_highlighted
+					segment['_rendered_raw'] += contents_raw
+					segment['_rendered_hl'] += contents_highlighted
 				else:
-					segment['rendered_raw'] += contents_raw
-					rendered_highlighted += contents_highlighted
-		rendered_highlighted += self.hl()
-		return rendered_highlighted
+					segment['_rendered_raw'] += contents_raw
+					segment['_rendered_hl'] += contents_highlighted
+			segment['_len'] = len(segment['_rendered_raw'])
+			# Replace rendered spaces with no-break spaces
+			segment['_rendered_hl'] = segment['_rendered_hl'].replace(' ', u'\u00a0')
+			yield segment
 
 	@staticmethod
-	def _total_len(segments):
-		'''Return total/rendered length of all segments.
-
-		This method uses the rendered_raw property of the segments and requires
-		that the segments have been rendered using the render() method first.
-		'''
-		return len(''.join([segment['rendered_raw'] for segment in segments]))
+	def _returned_value(rendered_highlighted, segments, output_raw):
+		if output_raw:
+			return rendered_highlighted, ''.join((segment['_rendered_raw'] for segment in segments))
+		else:
+			return rendered_highlighted
 
 	@staticmethod
 	def escape(string):

powerline/renderers/vim.py

@@ -38,6 +38,9 @@ def render(self, winnr, current):
 		else:
 			mode = 'nc'
 			theme, segments = self.window_cache.get(window_id, (None, None))
+			for segment in segments:
+				segment['_space_left'] = 0
+				segment['_space_right'] = 0
 		statusline = super(VimRenderer, self).render(mode, winwidth, theme, segments)
 		return statusline
 

powerline/segment.py

@@ -45,11 +45,16 @@ def get(self, segment, side):
 			'contents_func': contents_func,
 			'contents': contents,
 			'args': segment.get('args', {}),
-			'ljust': segment.get('ljust', False),
-			'rjust': segment.get('rjust', False),
 			'priority': segment.get('priority', -1),
 			'draw_divider': segment.get('draw_divider', True),
 			'side': side,
 			'exclude_modes': segment.get('exclude_modes', []),
 			'include_modes': segment.get('include_modes', []),
+			'width': segment.get('width'),
+			'align': segment.get('align', 'l'),
+			'_rendered_raw': u'',
+			'_rendered_hl': u'',
+			'_len': 0,
+			'_space_left': 0,
+			'_space_right': 0,
 			}

powerline/theme.py

@@ -65,15 +65,21 @@ def get_segments(self, side=None):
 					else:
 						segment['contents'] = contents
 						parsed_segments.append(segment)
-				elif segment['type'] == 'filler' or (segment['type'] == 'string' and segment['contents'] is not None):
+				elif segment['width'] == 'auto' or (segment['type'] == 'string' and segment['contents'] is not None):
 					parsed_segments.append(segment)
 				else:
 					continue
 			for segment in parsed_segments:
 				segment = self.add_highlight(segment)
-				segment['contents'] = (segment['before'] + unicode(segment['contents']) + segment['after'])\
-					.ljust(segment['ljust'])\
-					.rjust(segment['rjust'])
+				segment['contents'] = segment['before'] + unicode(segment['contents'] if segment['contents'] is not None else '') + segment['after']
+				# Align segment contents
+				if segment['width'] and segment['width'] != 'auto':
+					if segment['align'] == 'l':
+						segment['contents'] = segment['contents'].ljust(segment['width'])
+					elif segment['align'] == 'r':
+						segment['contents'] = segment['contents'].rjust(segment['width'])
+					elif segment['align'] == 'c':
+						segment['contents'] = segment['contents'].center(segment['width'])
 				# We need to yield a copy of the segment, or else mode-dependent
 				# segment contents can't be cached correctly e.g. when caching
 				# non-current window contents for vim statuslines