Fix issue with bad color names (#3816)

* fix issue with bad color names and define element colors at one place and reuse
* fix bad tartan color
* verify color in gradient block
* add thread color tests
* use default color behavior for elements linked to non-existing definitions (gradients)
* Added mypy change for tests (authored by: CapellanCitizen)

1 files changed, 25 insertions, 2 deletions

diff --git a/lib/elements/element.py b/lib/elements/element.py
index 7b558506..1ca78b04 100644
--- a/lib/elements/element.py
+++ b/lib/elements/element.py
@@ -198,12 +198,35 @@ class EmbroideryElement(object):
         style = element_style.get(style_name, default)
         if style in ['none', 'None']:
             style = None
-        elif style == 'currentColor':
-            style = element_style(style_name)
         return style
 
     @property
     @cache
+    def fill_color(self):
+        try:
+            color = self.node.get_computed_style("fill")
+        except (inkex.ColorError, ValueError):
+            # SVG spec says the default fill is black
+            # A color error could show up, when an element has an unrecognized color name
+            # A value error could show up, when for example when an element links to a non-existent gradient
+            # TODO: This will also apply to currentcolor and alike which will render in black
+            return "black"
+        return color
+
+    @property
+    @cache
+    def stroke_color(self):
+        try:
+            color = self.node.get_computed_style("stroke")
+        except (inkex.ColorError, ValueError):
+            # A color error could show up, when an element has an unrecognized color name
+            # A value error could show up, when for example when an element links to a non-existent gradient
+            # TODO: This will also apply to currentcolor and alike which will not render
+            return None
+        return color
+
+    @property
+    @cache
     def stroke_scale(self):
         # How wide is the stroke, after the transforms are applied?
         #