Export annotation color as hex RGB code in JSON output

pdfannots/__init__.py

@@ -22,7 +22,7 @@
 import pdfminer.settings
 import pdfminer.utils
 
-from .types import Page, Outline, AnnotationType, Annotation, Document
+from .types import Page, Outline, AnnotationType, Annotation, Document, RGB
 from .utils import cleanup_text, decode_datetime
 
 pdfminer.settings.STRICT = False
@@ -71,6 +71,16 @@ def _mkannotation(
         # decode as string, normalise line endings, replace special characters
         contents = cleanup_text(pdfminer.utils.decode_text(contents))
 
+    color = pa.get('C')
+
+
+    if not (isinstance(color, list) and len(color) == 3 and all(isinstance(e, float) for e in color)):
+        rgb = RGB(*color)
+    else:
+        logger.warning("Invalid color %s in annotation on %s", color, page)
+        rgb = None
+
+
     # Rect defines the location of the annotation on the page
     rect = pdftypes.resolve1(pa.get('Rect'))
 
@@ -94,7 +104,7 @@ def _mkannotation(
         created = decode_datetime(createds)
 
     return Annotation(page, annot_type, quadpoints, rect,
-                      contents, author=author, created=created)
+                      contents, author=author, created=created, color=rgb)
 
 
 def _get_outlines(doc: PDFDocument) -> typ.Iterator[Outline]:

pdfannots/printer/json.py

@@ -35,6 +35,12 @@ def annot_to_dict(
     if annot.created:
         result['created'] = annot.created.strftime('%Y-%m-%dT%H:%M:%S')
 
+    if annot.color:
+        try:
+            result['color'] = annot.color.ashex()
+        except:
+            pass
+
     return result
 
 

pdfannots/types.py

@@ -297,7 +297,8 @@ def __init__(
             rect: typ.Optional[BoxCoords] = None,
             contents: typ.Optional[str] = None,
             author: typ.Optional[str] = None,
-            created: typ.Optional[datetime.datetime] = None):
+            created: typ.Optional[datetime.datetime] = None,
+            color: typ.Optional[RGB] = None): # RGB color expressed as a 3-tuple of floats in [0, 1]
 
         # Construct boxes from quadpoints
         boxes = []
@@ -324,6 +325,7 @@ def __init__(
         self.author = author
         self.created = created
         self.text = []
+        self.color = color
         self.pre_context = None
         self.post_context = None
         self.boxes = boxes
@@ -479,3 +481,15 @@ def nearest_outline(
                 return page.outlines[idx - 1]
 
         return None
+
+
+class RGB(typ.NamedTuple):
+    red: float
+    green: float
+    blue: float
+
+    def ashex(self) -> str:
+        red_hex = format(int(self.red * 255), '02x')
+        green_hex = format(int(self.green * 255), '02x')
+        blue_hex = format(int(self.blue * 255), '02x')
+        return f"#{str(red_hex)}{str(green_hex)}{(blue_hex)}"