Fix graph crash on reload, even out depth sizes

Client/Graph.py

@@ -220,8 +220,11 @@ class Layout:
 # Directories go down the heading colours by depth (h1 Mauve, h2 Blue, ...),
 # starting again after Red. Files are White.
 DepthColours = ["Mauve", "Blue", "Green", "Yellow", "Peach", "Red"]
-ShrinkPerDepth = 0.8  # with GraphShrinkByDepth, each level's directory dots are this much smaller
-SmallestDirectory = 3  # ...but never smaller than a file's dot
+# With GraphShrinkByDepth, directory dots shrink in even steps from their
+# usual size to a file dot's size (a file with one link) at this depth (the
+# red ones), and stay that size below it.
+ShrinkDepth = 5
+FileDotRadius = 3.8
 
 
 def DirectoryColour(Depth: int) -> str:
@@ -370,17 +373,22 @@ class GraphView(ft.Container):
             self.Status.value = "Nothing to show here."
             self.Status.update()
             return
-        self.Layout = Layout(Graph)
+        # This thread keeps its own Layout: a Reload meanwhile (the graph
+        # opening, or the scope changing) clears self.Layout for its own thread.
+        Settling = Layout(Graph)
         Base = len(Path.split("/")) if Path else 0
-        self.Depths = np.array([(len(Node["Id"].split("/")) if Node["Id"] else 0) - Base for Node in self.Layout.Nodes])
-        self.Colours = [(DirectoryColour(int(Depth)) if self.ColourByDepth else Palette.Mauve) if Node["IsDirectory"]
-                        else Palette.White for Node, Depth in zip(self.Layout.Nodes, self.Depths)]
+        Depths = np.array([(len(Node["Id"].split("/")) if Node["Id"] else 0) - Base for Node in Settling.Nodes])
+        Colours = [(DirectoryColour(int(Depth)) if self.ColourByDepth else Palette.Mauve) if Node["IsDirectory"]
+                   else Palette.White for Node, Depth in zip(Settling.Nodes, Depths)]
+        if Generation != self.Generation or self.Closed:
+            return
+        self.Layout, self.Depths, self.Colours = Settling, Depths, Colours
         self.StatusBox.visible = False
         self.StatusBox.update()
         # Settle in steps, drawing as it goes, like the web view's animation.
-        while not self.Layout.Settled:
+        while not Settling.Settled:
             for _ in range(TicksPerDraw):
-                self.Layout.Tick()
+                Settling.Tick()
             if Generation != self.Generation or self.Closed:
                 return
             self._Draw()
@@ -403,7 +411,8 @@ class GraphView(ft.Container):
         Degree = np.sqrt(self.Layout.Degree)
         DirectoryRadius = 5 + Degree * 1.6
         if self.ShrinkByDepth:
-            DirectoryRadius = np.maximum(SmallestDirectory, DirectoryRadius * ShrinkPerDepth ** self.Depths)
+            Step = np.minimum(self.Depths, ShrinkDepth) / ShrinkDepth
+            DirectoryRadius = DirectoryRadius + (FileDotRadius - DirectoryRadius) * Step
         self.Radius = np.maximum(2, np.where(IsDirectory, DirectoryRadius, 3 + Degree * 0.8) * Zoom)
 
     def _Label(self, Number: int, Colour: str) -> cv.Text: