Add strip length specs for connectors (port of upstream PR #446)

Connectors now support a 'strip' property with sleeve and insulation
length specifications, rendered in the diagram node and available in
the data model for BOM/manufacturing use.

src/wireviz/wireviz.py

@@ -14,6 +14,7 @@ if __name__ == "__main__":
 
 from wireviz.wv_dataclasses import AUTOGENERATED_PREFIX, Metadata, Options, Tweak
 from wireviz.wv_harness import Harness
+from wireviz.wv_png_metadata import save_yaml_to_png
 from wireviz.wv_utils import (
     expand,
     file_read_text,
@@ -88,7 +89,7 @@ def parse(
     if not output_formats and not return_types:
         raise Exception("No output formats or return types specified")
 
-    yaml_data, yaml_file = _get_yaml_data_and_path(inp)
+    yaml_data, yaml_file, yaml_str = _get_yaml_data_and_path(inp)
     if not isinstance(yaml_data, dict):
         raise TypeError(
             f"Expected a dict as top-level YAML input, but got: {type(yaml_data)}"
@@ -394,6 +395,9 @@ def parse(
 
     if output_formats:
         harness.output(filename=output_file, fmt=output_formats, view=False)
+        # embed YAML source into PNG for round-trip capability
+        if "png" in output_formats and yaml_str:
+            save_yaml_to_png(output_file, yaml_str)
 
     if return_types:
         returns = []
@@ -413,7 +417,7 @@ def parse(
         return tuple(returns) if len(returns) != 1 else returns[0]
 
 
-def _get_yaml_data_and_path(inp: Union[str, Path, Dict]) -> Tuple[Dict, Path]:
+def _get_yaml_data_and_path(inp: Union[str, Path, Dict]) -> Tuple[Dict, Path, str]:
     # determine whether inp is a file path, a YAML string, or a Dict
     if not isinstance(inp, Dict):  # received a str or a Path
         try:
@@ -441,7 +445,8 @@ def _get_yaml_data_and_path(inp: Union[str, Path, Dict]) -> Tuple[Dict, Path]:
         # received a Dict, use as-is
         yaml_data = inp
         yaml_path = None
-    return yaml_data, yaml_path
+        yaml_str = None
+    return yaml_data, yaml_path, yaml_str
 
 
 def _get_output_dir(input_file: Path, default_output_dir: Path) -> Path:

src/wireviz/wv_cli.py

@@ -19,7 +19,7 @@ format_codes = {
     "g": "gv",
     "h": "html",
     "p": "png",
-    # "P": "pdf",  # TODO: support PDF
+    "P": "pdf",
     "s": "svg",
     "t": "tsv",
 }

src/wireviz/wv_dataclasses.py

@@ -293,6 +293,42 @@ class AdditionalComponent(GraphicalComponent):
             self.explicit_qty = False
 
 
+@dataclass
+class StripSpec:
+    """Strip length specification for sleeve or insulation."""
+    length: float = 0
+    length_unit: str = "mm"
+
+    def __str__(self) -> str:
+        return f"{self.length} {self.length_unit}" if self.length > 0 else ""
+
+
+@dataclass
+class Strip:
+    """Wire stripping specifications for a connector."""
+    sleeve: Optional[StripSpec] = None
+    insulation: Optional[StripSpec] = None
+
+    def __post_init__(self) -> None:
+        if isinstance(self.sleeve, str):
+            self.sleeve = Strip._parse_length(self.sleeve)
+        if isinstance(self.insulation, str):
+            self.insulation = Strip._parse_length(self.insulation)
+
+    @staticmethod
+    def _parse_length(spec: str) -> StripSpec:
+        parts = spec.strip().split(" ", 1)
+        try:
+            length = float(parts[0])
+        except (ValueError, IndexError):
+            raise Exception(
+                f"Strip length '{spec}' must be a number, "
+                "or number and unit separated by a space"
+            )
+        unit = parts[1].strip() if len(parts) > 1 else "mm"
+        return StripSpec(length=length, length_unit=unit)
+
+
 @dataclass
 class TopLevelGraphicalComponent(GraphicalComponent):  # abstract class
     # component properties
@@ -317,6 +353,7 @@ class Connector(TopLevelGraphicalComponent):
     shorts_hide_lable: bool = False
     # pin information in particular
     pincount: Optional[int] = None
+    strip: Optional[Strip] = None
     pins: List[Pin] = field(default_factory=list)  # legacy
     pinlabels: List[Pin] = field(default_factory=list)  # legacy
     pincolors: List[str] = field(default_factory=list)  # legacy
@@ -367,6 +404,11 @@ class Connector(TopLevelGraphicalComponent):
         if isinstance(self.image, dict):
             self.image = Image(**self.image)
 
+        if isinstance(self.strip, dict):
+            self.strip = Strip(**self.strip)
+        elif self.strip is None:
+            self.strip = Strip()
+
         self.ports_left = False
         self.ports_right = False
         self.visible_pins = {}

src/wireviz/wv_graphviz.py

@@ -63,6 +63,16 @@ def gv_node_component(component: Component) -> Table:
             str(component.color) if component.color else None,
         ]
 
+    # strip info for connectors
+    line_strip = None
+    if isinstance(component, Connector) and (component.strip.sleeve or component.strip.insulation):
+        strip_parts = []
+        if component.strip.sleeve:
+            strip_parts.append(f"Strip sleeve: {component.strip.sleeve}")
+        if component.strip.insulation:
+            strip_parts.append(f"Strip insulation: {component.strip.insulation}")
+        line_strip = [Td(" | ".join(strip_parts))]
+
     if component.additional_parameters:
         line_additional_parameters = nested_table_dict(component.additional_parameters)
     else:
@@ -87,6 +97,7 @@ def gv_node_component(component: Component) -> Table:
         line_name,
         line_pn,
         line_info,
+        line_strip,
         line_additional_parameters,
         line_ports,
         line_image,

src/wireviz/wv_harness.py

@@ -440,7 +440,7 @@ class Harness:
         # graphical output
         graph = self.graph
         for f in fmt:
-            if f in ("png", "svg", "html"):
+            if f in ("png", "svg", "html", "pdf"):
                 if f == "html":  # if HTML format is specified,
                     f = "svg"  # generate SVG for embedding into HTML
                 # SVG file will be renamed/deleted later
@@ -471,10 +471,7 @@ class Harness:
         # HTML output
         if "html" in fmt:
             generate_html_output(filename, bomlist, self.metadata, self.options)
-        # PDF output
-        if "pdf" in fmt:
-            # TODO: implement PDF output
-            print("PDF output is not yet supported")
+        # PDF output is handled by GraphViz in the format loop above
         # delete SVG if not needed
         if "html" in fmt and not "svg" in fmt:
             # SVG file was just needed to generate HTML

src/wireviz/wv_png_metadata.py

@@ -0,0 +1,63 @@
+# -*- coding: utf-8 -*-
+
+"""Embed and extract YAML source data in PNG metadata (iTXT chunks)."""
+
+from pathlib import Path
+from typing import Optional, Tuple
+
+from PIL import Image
+from PIL.PngImagePlugin import PngInfo
+
+
+PNG_KEY_YAML = "wireviz_yaml"
+PNG_KEY_PREPEND = "wireviz_prepend_yaml"
+
+
+def save_yaml_to_png(
+    png_path: Path,
+    yaml_input: str,
+    prepend_input: str = "",
+) -> None:
+    """Save YAML source as compressed iTXT metadata in a PNG file."""
+    png_path = Path(png_path)
+    if not png_path.suffix == ".png":
+        png_path = png_path.with_suffix(".png")
+    if not png_path.exists():
+        return
+
+    with Image.open(fp=png_path) as im:
+        txt = PngInfo()
+        txt.add_itxt(PNG_KEY_YAML, yaml_input, zip=True)
+        if prepend_input:
+            txt.add_itxt(PNG_KEY_PREPEND, prepend_input, zip=True)
+        im.save(fp=png_path, pnginfo=txt)
+
+
+def read_yaml_from_png(png_path: Path) -> Tuple[str, Optional[str]]:
+    """Extract YAML source from a PNG file's iTXT metadata.
+
+    Returns (yaml_input, prepend_input) where prepend_input may be None.
+    """
+    png_path = Path(png_path)
+    if not png_path.suffix == ".png":
+        png_path = png_path.with_suffix(".png")
+
+    with Image.open(fp=png_path) as im:
+        im.load()
+        yaml_input = im.text.get(PNG_KEY_YAML, "")
+        prepend_input = im.text.get(PNG_KEY_PREPEND)
+
+    return yaml_input, prepend_input
+
+
+def has_yaml_metadata(png_path: Path) -> bool:
+    """Check if a PNG file contains embedded WireViz YAML data."""
+    png_path = Path(png_path)
+    if not png_path.suffix == ".png":
+        png_path = png_path.with_suffix(".png")
+    if not png_path.exists():
+        return False
+
+    with Image.open(fp=png_path) as im:
+        im.load()
+        return PNG_KEY_YAML in im.text