Add bgcolor attribute to connectors and cables

This solves the wireviz#210 suggestion to render the title row of
the graph nodes with this bgcolor.

docs/syntax.md

@@ -62,6 +62,7 @@ additional_bom_items:  # custom items to add to BOM
                      # no color marks will be added to remaining pins
 
   # rendering information (all optional)
+  bgcolor: <color>       # Background color of diagram connector box
   style: <style>         # may be set to simple for single pin connectors
   show_name: <bool>      # defaults to true for regular connectors,
                          # false for simple connectors
@@ -137,6 +138,7 @@ Since the auto-incremented and auto-assigned designator is not known to the user
   wirelabels: <List>  # optional; one label for each wire
 
   # rendering information (all optional)
+  bgcolor: <color>          # Background color of diagram cable box
   show_name: <bool>         # defaults to true
   show_wirecount: <bool>    # defaults to true
   show_wirenumbers: <bool>  # defaults to true for cables; false for bundles

src/wireviz/DataClasses.py

@@ -86,6 +86,7 @@ def description(self) -> str:
 @dataclass
 class Connector:
     name: Designator
+    bgcolor: Optional[Color] = None
     manufacturer: Optional[MultilineHypertext] = None
     mpn: Optional[MultilineHypertext] = None
     pn: Optional[Hypertext] = None
@@ -168,6 +169,7 @@ def get_qty_multiplier(self, qty_multiplier: Optional[ConnectorMultiplier]) -> i
 @dataclass
 class Cable:
     name: Designator
+    bgcolor: Optional[Color] = None
     manufacturer: Union[MultilineHypertext, List[MultilineHypertext], None] = None
     mpn: Union[MultilineHypertext, List[MultilineHypertext], None] = None
     pn: Union[Hypertext, List[Hypertext], None] = None

src/wireviz/Harness.py

@@ -11,8 +11,8 @@
 from wireviz import wv_colors, __version__, APP_NAME, APP_URL
 from wireviz.DataClasses import Connector, Cable
 from wireviz.wv_colors import get_color_hex
-from wireviz.wv_gv_html import nested_html_table, html_colorbar, html_image, \
-    html_caption, remove_links, html_line_breaks
+from wireviz.wv_gv_html import nested_html_table, html_bgcolor, html_colorbar, \
+    html_image, html_caption, remove_links, html_line_breaks
 from wireviz.wv_bom import manufacturer_info_field, component_table_entry, \
     get_additional_component_table, bom_list, generate_bom
 from wireviz.wv_html import generate_html_output
@@ -120,7 +120,7 @@ def create_graph(self) -> Graph:
 
             html = []
 
-            rows = [[remove_links(connector.name) if connector.show_name else None],
+            rows = [[f'{html_bgcolor(connector.bgcolor)}{remove_links(connector.name)}' if connector.show_name else None],
                     [f'P/N: {remove_links(connector.pn)}' if connector.pn else None,
                      html_line_breaks(manufacturer_info_field(connector.manufacturer, connector.mpn))],
                     [html_line_breaks(connector.type),
@@ -201,7 +201,7 @@ def create_graph(self) -> Graph:
                 elif cable.gauge_unit.upper() == 'AWG':
                     awg_fmt = f' ({mm2_equiv(cable.gauge)} mm\u00B2)'
 
-            rows = [[remove_links(cable.name) if cable.show_name else None],
+            rows = [[f'{html_bgcolor(cable.bgcolor)}{remove_links(cable.name)}' if cable.show_name else None],
                     [f'P/N: {remove_links(cable.pn)}' if (cable.pn and not isinstance(cable.pn, list)) else None,
                      html_line_breaks(manufacturer_info_field(
                         cable.manufacturer if not isinstance(cable.manufacturer, list) else None,

src/wireviz/wv_gv_html.py

@@ -4,6 +4,7 @@
 from typing import List, Union
 import re
 
+from wireviz.DataClasses import Color
 from wireviz.wv_colors import translate_color
 from wireviz.wv_helper import remove_links
 
@@ -32,8 +33,13 @@ def nested_html_table(rows):
     html.append('</table>')
     return html
 
-def html_colorbar(color):
-    return f'<tdX bgcolor="{translate_color(color, "HEX")}" width="4">' if color else None
+def html_bgcolor(color: Color, _extra_attr: str = '') -> str:
+    """Return <td> attributes prefix for bgcolor or '' if no color."""
+    return f'<tdX bgcolor="{translate_color(color, "HEX")}"{_extra_attr}>' if color else ''
+
+def html_colorbar(color: Color) -> str:
+    """Return <tdX> attributes prefix for bgcolor and minimum width or None if no color."""
+    return html_bgcolor(color, ' width="4"') if color else None
 
 def html_image(image):
     from wireviz.DataClasses import Image