Fixed inconsistent default color in vp.write_svg().

The default color (from the default color scheme) for a layer would depend on whether previous layer would have their color specified on not. This is an inconsistent behaviour in itself, and it is inconsistent with the viewer's behaviour. Also, the default color scheme as been moved to vpype/metadata.py.
abey79 · Jan 16, 2022 · 6e6d0f1 · 6e6d0f1
1 parent f49c658
commit 6e6d0f1
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Showing 3 changed files with 26 additions and 25 deletions.
diff --git a/vpype/io.py b/vpype/io.py
@@ -18,6 +18,7 @@
 
 from .config import PaperConfig, PlotterConfig, config_manager
 from .metadata import (
+    METADATA_DEFAULT_COLOR_SCHEME,
     METADATA_FIELD_COLOR,
     METADATA_FIELD_NAME,
     METADATA_FIELD_PEN_WIDTH,
@@ -31,17 +32,6 @@
 __all__ = ["read_svg", "read_multilayer_svg", "write_svg", "write_hpgl"]
 
 
-_COLORS = [
-    "#00f",
-    "#080",
-    "#f00",
-    "#0cc",
-    "#0f0",
-    "#c0c",
-    "#cc0",
-    "black",
-]
-
 _DEFAULT_WIDTH = 1000
 _DEFAULT_HEIGHT = 1000
 
@@ -583,10 +573,16 @@ def write_svg(
         if color_mode == "layer" or (
             color_mode == "default" and not layer.property_exists(METADATA_FIELD_COLOR)
         ):
-            group.attribs["stroke"] = _COLORS[color_idx % len(_COLORS)]
+            group.attribs["stroke"] = METADATA_DEFAULT_COLOR_SCHEME[
+                color_idx % len(METADATA_DEFAULT_COLOR_SCHEME)
+            ]
             color_idx += 1
         elif color_mode == "default":
             group.attribs["stroke"] = str(layer.property(METADATA_FIELD_COLOR))
+
+            # we want to avoid a subsequent layer whose color is undefined to have its color
+            # affected by whether or not previous layer have their color defined
+            color_idx += 1
         elif color_mode == "none":
             group.attribs["stroke"] = "black"
         group.attribs["style"] = "display:inline"
@@ -612,7 +608,9 @@ def write_svg(
                 path = dwg.polyline((c.real, c.imag) for c in line)
 
             if color_mode == "path":
-                path.attribs["stroke"] = _COLORS[color_idx % len(_COLORS)]
+                path.attribs["stroke"] = METADATA_DEFAULT_COLOR_SCHEME[
+                    color_idx % len(METADATA_DEFAULT_COLOR_SCHEME)
+                ]
                 color_idx += 1
             group.add(path)
 

diff --git a/vpype/metadata.py b/vpype/metadata.py
@@ -147,3 +147,15 @@ def __str__(self) -> str:
     "stroke-width",
     "text-rendering",
 }
+
+
+METADATA_DEFAULT_COLOR_SCHEME = [
+    Color("#00f"),
+    Color("#080"),
+    Color("#f00"),
+    Color("#0cc"),
+    Color("#0f0"),
+    Color("#c0c"),
+    Color("#cc0"),
+    Color("black"),
+]
diff --git a/vpype_viewer/engine.py b/vpype_viewer/engine.py
@@ -23,17 +23,6 @@
 from ._scales import DEFAULT_SCALE_SPEC, SCALES_MAP, ScaleSpec, UnitType
 from ._utils import ColorType, orthogonal_projection_matrix
 
-_COLORS: List[ColorType] = [
-    (0, 0, 1, 1),
-    (0, 0.5, 0, 1),
-    (1, 0, 0, 1),
-    (0, 0.75, 0.75, 1),
-    (0, 1, 0, 1),
-    (0.75, 0, 0.75, 1),
-    (0.75, 0.75, 0, 1),
-    (0, 0, 0, 1),
-]
-
 __all__ = ["DEFAULT_PEN_WIDTH", "DEFAULT_PEN_OPACITY", "ViewMode", "Engine"]
 
 DEFAULT_PEN_WIDTH = 1.1  # about 0.3mm
@@ -426,7 +415,9 @@ def _rebuild(self):
         if self._document is not None:
             color_index = 0
             for layer_id in sorted(self._document.layers):
-                layer_color: ColorType = _COLORS[color_index % len(_COLORS)]
+                layer_color: ColorType = vp.METADATA_DEFAULT_COLOR_SCHEME[
+                    color_index % len(vp.METADATA_DEFAULT_COLOR_SCHEME)
+                ].as_floats()
                 color_index += 1
 
                 lc = self._document.layers[layer_id]