Add Option to Make Trail Shade Darker/Lighter (#1103)

* Make trails 60% darker than track color

* Add menu option for shade of trails

* Remove unexpected indent (fat-fingered)

sleap/gui/app.py

@@ -156,6 +156,7 @@ def __init__(
         self.state["edge style"] = prefs["edge style"]
         self.state["fit"] = False
         self.state["color predicted"] = prefs["color predicted"]
+        self.state["trail_shade"] = prefs["trail shade"]
         self.state["marker size"] = prefs["marker size"]
         self.state["propagate track labels"] = prefs["propagate track labels"]
         self.state["node label size"] = prefs["node label size"]
@@ -218,6 +219,7 @@ def closeEvent(self, event):
         prefs["edge style"] = self.state["edge style"]
         prefs["propagate track labels"] = self.state["propagate track labels"]
         prefs["color predicted"] = self.state["color predicted"]
+        prefs["trail shade"] = self.state["trail_shade"]
         prefs["share usage data"] = self.state["share usage data"]
 
         # Save preferences.
@@ -632,12 +634,19 @@ def prev_vid():
             key="node label size",
         )
 
+        viewMenu.addSeparator()
         add_submenu_choices(
             menu=viewMenu,
             title="Trail Length",
-            options=(0, 10, 50, 100, 250),
+            options=TrackTrailOverlay.get_length_options(),
             key="trail_length",
         )
+        add_submenu_choices(
+            menu=viewMenu,
+            title="Trail Shade",
+            options=tuple(TrackTrailOverlay.get_shade_options().keys()),
+            key="trail_shade",
+        )
 
         viewMenu.addSeparator()
         add_menu_item(
@@ -1177,7 +1186,11 @@ def goto_suggestion(*args):
     def _load_overlays(self):
         """Load all standard video overlays."""
         self.overlays["track_labels"] = TrackListOverlay(self.labels, self.player)
-        self.overlays["trails"] = TrackTrailOverlay(self.labels, self.player)
+        self.overlays["trails"] = TrackTrailOverlay(
+            labels=self.labels,
+            player=self.player,
+            trail_shade=self.state["trail_shade"],
+        )
         self.overlays["instance"] = InstanceOverlay(
             self.labels, self.player, self.state
         )
@@ -1196,6 +1209,7 @@ def overlay_state_connect(overlay, state_key, overlay_attribute=None):
             )
 
         overlay_state_connect(self.overlays["trails"], "trail_length")
+        overlay_state_connect(self.overlays["trails"], "trail_shade")
 
         overlay_state_connect(self.color_manager, "palette")
         overlay_state_connect(self.color_manager, "distinctly_color")

sleap/gui/overlays/tracks.py

@@ -1,6 +1,5 @@
-"""
-Track trail and track list overlays.
-"""
+"""Track trail and track list overlays."""
+
 from sleap.gui.overlays.base import BaseOverlay
 from sleap.instance import Track
 from sleap.io.dataset import Labels
@@ -10,7 +9,7 @@
 
 import attr
 
-from typing import Iterable, List, Optional
+from typing import Iterable, List, Optional, Dict
 
 from qtpy import QtCore, QtGui
 
@@ -27,16 +26,36 @@ class TrackTrailOverlay(BaseOverlay):
         labels: The :class:`Labels` dataset from which to get overlay data.
         player: The video player in which to show overlay.
         trail_length: The maximum number of frames to include in trail.
+        trail_shade: A literal "Dark", "Normal", or "Bright" which determines the shade
+            of the trail color.
 
     Usage:
         After class is instantiated, call :meth:`add_to_scene(frame_idx)`
         to plot the trails in scene.
     """
 
     trail_length: int = 0
+    trail_shade: str = attr.ib(
+        default="Normal", validator=attr.validators.in_(["Dark", "Normal", "Light"])
+    )
     show: bool = True
     max_node_count: Optional[int] = None
 
+    def __attrs_post_init__(self):
+        """Initialize the shade options attribute after initalizing the instance."""
+
+        self.shade_options = self.get_shade_options()
+
+    @classmethod
+    def get_length_options(cls):
+        return (0, 10, 50, 100, 250)
+
+    @classmethod
+    def get_shade_options(cls):
+        """Return a dictionary with values to multiply each RGB value by."""
+
+        return {"Dark": 0.6, "Normal": 1.0, "Light": 1.25}
+
     def get_track_trails(self, frame_selection: Iterable["LabeledFrame"]):
         """Get data needed to draw track trail.
 
@@ -85,9 +104,7 @@ def get_track_trails(self, frame_selection: Iterable["LabeledFrame"]):
         return all_track_trails
 
     def get_frame_selection(self, video: Video, frame_idx: int):
-        """
-        Return `LabeledFrame` objects to include in trail for specified frame.
-        """
+        """Return `LabeledFrame` objects to include in trail for specified frame."""
 
         frame_selection = self.labels.find(video, range(0, frame_idx + 1))
         frame_selection.sort(key=lambda x: x.frame_idx)
@@ -97,8 +114,7 @@ def get_frame_selection(self, video: Video, frame_idx: int):
     def get_tracks_in_frame(
         self, video: Video, frame_idx: int, include_trails: bool = False
     ) -> List[Track]:
-        """
-        Returns list of tracks that have instance in specified frame.
+        """Returns list of tracks that have instance in specified frame.
 
         Args:
             video: Video for which we want tracks.
@@ -108,6 +124,7 @@ def get_tracks_in_frame(
                 within trail_length).
         Returns:
             List of tracks.
+
         """
 
         if include_trails:
@@ -125,7 +142,9 @@ def add_to_scene(self, video: Video, frame_idx: int):
         Args:
             video: current video
             frame_idx: index of the frame to which the trail is attached
+
         """
+
         if not self.show or self.trail_length == 0:
             return
 
@@ -134,8 +153,11 @@ def add_to_scene(self, video: Video, frame_idx: int):
         all_track_trails = self.get_track_trails(frame_selection)
 
         for track, trails in all_track_trails.items():
-
-            color = QtGui.QColor(*self.player.color_manager.get_track_color(track))
+            trail_color = tuple(
+                min(c * self.shade_options[self.trail_shade], 255)
+                for c in self.player.color_manager.get_track_color(track)
+            )
+            color = QtGui.QColor(*trail_color)
             pen = QtGui.QPen()
             pen.setCosmetic(True)
             pen.setColor(color)
@@ -183,9 +205,7 @@ def map_to_qt_path(point_list):
 
 @attr.s(auto_attribs=True)
 class TrackListOverlay(BaseOverlay):
-    """
-    Class to show track number and names in overlay.
-    """
+    """Class to show track number and names in overlay."""
 
     text_box: Optional[QtTextWithBackground] = None
 

sleap/prefs.py

@@ -19,6 +19,7 @@ class Preferences(object):
         "palette": "standard",
         "bold lines": False,
         "trail length": 0,
+        "trail shade": "Normal",
         "trail width": 4.0,
         "trail node count": 1,
         "marker size": 4,