Add support for (0, None) and (0, ()) linestyle as a valid style for solid line

Author: t20100

src/silx/gui/plot/backends/BackendBase.py

@@ -216,7 +216,7 @@ def addMarker(
         text: str | None,
         color: str,
         symbol: str | None,
-        linestyle: str | tuple[float, tuple[float, ...]],
+        linestyle: str | tuple[float, tuple[float, ...] | None],
         linewidth: float,
         constraint: Callable[[float, float], tuple[float, float]] | None,
         yaxis: str,

src/silx/gui/plot/backends/BackendOpenGL.py

@@ -875,7 +875,7 @@ def _castArrayTo(v):
         else:
             raise ValueError("Unsupported data type")
 
-    _DASH_PATTERNS = {  # Convert from linestyle to offset and dash pattern
+    _DASH_PATTERNS = {
         "": (0.0, None),
         " ": (0.0, None),
         "-": (0.0, ()),
@@ -884,6 +884,12 @@ def _castArrayTo(v):
         ":": (0.0, (1, 1.65, 1, 1.65)),
         None: (0.0, None),
     }
+    """Convert from linestyle to (offset, (dash pattern))
+
+    Note: dash pattern internal convention differs from matplotlib:
+    - None: no line at all
+    - (): "solid" line
+    """
 
     def _lineStyleToDashOffsetPattern(
         self, style
@@ -892,8 +898,11 @@ def _lineStyleToDashOffsetPattern(
         if style is None or isinstance(style, str):
             return self._DASH_PATTERNS[style]
 
-        # (offset, (dash pattern))
+        # (offset, (dash pattern)) case
         offset, pattern = style
+        if pattern is None:
+            # Convert from matplotlib to internal representation of solid
+            pattern = ()
         if len(pattern) == 2:
             pattern = pattern * 2
         return offset, pattern

src/silx/gui/plot/items/core.py

@@ -837,6 +837,7 @@ def setSymbolSize(self, size):
 
 LineStyleType = Union[
     str,
+    Tuple[float, None],
     Tuple[float, Tuple[float, float]],
     Tuple[float, Tuple[float, float, float, float]],
 ]
@@ -888,9 +889,15 @@ def isValidLineStyle(cls, style: LineStyleType | None) -> bool:
         if (
             len(style) == 2
             and isinstance(style[0], float)
-            and isinstance(style[1], tuple)
-            and len(style[1]) in (2, 4)
-            and all(map(lambda item: isinstance(item, float), style[1]))
+            and (
+                style[1] is None
+                or style[1] == ()
+                or (
+                    isinstance(style[1], tuple)
+                    and len(style[1]) in (2, 4)
+                    and all(map(lambda item: isinstance(item, float), style[1]))
+                )
+            )
         ):
             return True
         return False