add argument for preventing crossings

adjustText/__init__.py

@@ -22,7 +22,7 @@
     matplot_get_renderer = None
 
 
-# From https://gist.github.com/kylemcdonald/6132fc1c29fd3767691442ba4bc84018
+# Modified from https://gist.github.com/kylemcdonald/6132fc1c29fd3767691442ba4bc84018
 def intersect(seg1, seg2):
     x1, y1, x2, y2 = seg1
     x3, y3, x4, y4 = seg2
@@ -437,6 +437,7 @@ def adjust_text(
     target_x=None,
     target_y=None,
     avoid_self=True,
+    prevent_crossings=True,
     force_text: tuple[float, float] | float = (0.1, 0.2),
     force_static: tuple[float, float] | float = (0.1, 0.2),
     force_pull: tuple[float, float] | float = (0.01, 0.01),
@@ -498,6 +499,8 @@ def adjust_text(
         Should be the same length as texts and in the same order, or None.
     avoid_self : bool, default True
         whether to repel texts from its original positions.
+    prevent_crossings : bool, default True
+        whether to prevent arrows from crossing each other [NEW, EXPERIMENTAL]
     force_text : tuple[float, float] | float, default (0.1, 0.2)
         the repel force from texts is multiplied by this value
     force_static : tuple[float, float] | float, default (0.1, 0.2)
@@ -708,28 +711,30 @@ def adjust_text(
             bbox_to_contain=ax_bbox,
             only_move=only_move,
         )
-        connections = np.hstack(
-            [
-                np.mean(coords[:, :2], axis=1)[:, np.newaxis],
-                np.mean(coords[:, 2:], axis=1)[:, np.newaxis],
-                target_xy_disp_coord,
-            ]
-        )
-        for i, seg1 in enumerate(connections):
-            for j, seg2 in enumerate(connections):
-                if i >= j:
-                    continue
-                inter = intersect(seg1, seg2)
-                if inter:
-                    coords[i], coords[j] = coords[j].copy(), coords[i].copy()
+        if prevent_crossings:
+            connections = np.hstack(
+                [
+                    np.mean(coords[:, :2], axis=1)[:, np.newaxis],
+                    np.mean(coords[:, 2:], axis=1)[:, np.newaxis],
+                    target_xy_disp_coord,
+                ]
+            )
+            for i, seg1 in enumerate(connections):
+                for j, seg2 in enumerate(connections):
+                    if i >= j:
+                        continue
+                    inter = intersect(seg1, seg2)
+                    if inter:
+                        logger.debug(f"Removing crossing at step {step}: {i} and {j}")
+                        coords[i], coords[j] = coords[j].copy(), coords[i].copy()
 
         step += 1
         if time_lim is not None and timer() - start_time > time_lim:
             break
         if iter_lim is not None and i == iter_lim:
             break
 
-    logger.debug(f"Adjustment took {i} iterations")
+    logger.debug(f"Adjustment took {step} iterations")
     logger.debug(f"Time: {timer() - start_time}")
     logger.debug(f"Error: {error}")
 
@@ -742,7 +747,13 @@ def adjust_text(
         axis=1,
     )
     display_dists = np.max(np.vstack([xdists, ydists]), axis=0)
-
+    connections = np.hstack(
+        [
+            np.mean(coords[:, :2], axis=1)[:, np.newaxis],
+            np.mean(coords[:, 2:], axis=1)[:, np.newaxis],
+            target_xy_disp_coord,
+        ]
+    )
     transformed_connections = np.empty_like(connections)
     transformed_connections[:, :2] = transform.inverted().transform(connections[:, :2])
     transformed_connections[:, 2:] = transform.inverted().transform(connections[:, 2:])