Fix scaling of title

ultraplot/axes/base.py

@@ -2927,10 +2927,18 @@ def _update_title_position(self, renderer):
                         if base_x >= ax1 + abc_title_sep:
                             max_width = base_x - (ax1 + abc_title_sep)
                     elif ha == "center":
+                        # Keep the requested font size for centered titles and
+                        # resolve collisions by shifting the title away from the
+                        # abc label, matching the overflow-tolerant behavior of
+                        # left/right titles in practice.
                         if base_x >= ax1 + abc_title_sep:
-                            max_width = 2 * (base_x - (ax1 + abc_title_sep))
+                            shift = (ax1 + abc_title_sep) - tx0
+                            if shift > 0:
+                                title_obj.set_x(base_x + shift)
                         elif base_x <= ax0 - abc_title_sep:
-                            max_width = 2 * ((ax0 - abc_title_sep) - base_x)
+                            shift = (ax0 - abc_title_sep) - tx1
+                            if shift < 0:
+                                title_obj.set_x(base_x + shift)
                     if 0 < max_width < title_bbox.width:
                         scale = max_width / title_bbox.width
                         title_obj.set_fontsize(title_obj.get_fontsize() * scale)

ultraplot/tests/test_axes.py

@@ -342,16 +342,18 @@ def test_title_manual_size_ignores_auto_shrink():
     assert title_obj.get_fontsize() == 20
 
 
-def test_title_shrinks_when_abc_overlaps_different_loc():
+def test_title_shifts_when_abc_overlaps_different_loc():
     """
-    Ensure long titles shrink when overlapping abc at a different location.
+    Ensure centered titles keep their requested size by shifting away from abc.
     """
     fig, axs = uplt.subplots(figsize=(3, 2))
-    axs.format(abc=True, title="X" * 200, titleloc="center", abcloc="left")
+    axs.format(abc=True, title="X" * 100, titleloc="center", abcloc="left")
     title_obj = axs[0]._title_dict["center"]
     original_size = title_obj.get_fontsize()
+    original_x = title_obj.get_position()[0]
     fig.canvas.draw()
-    assert title_obj.get_fontsize() < original_size
+    assert title_obj.get_fontsize() == original_size
+    assert title_obj.get_position()[0] > original_x
 
 
 def test_title_shrinks_right_aligned_same_location():
@@ -418,17 +420,18 @@ def test_title_no_shrink_when_no_overlap():
     assert title_obj.get_fontsize() == original_size
 
 
-def test_title_shrinks_centered_left_of_abc():
+def test_title_shifts_centered_left_of_abc():
     """
-    Test that centered titles shrink when they are to the left of abc label.
-    This covers the specific case where base_x <= ax0 - pad for centered titles.
+    Centered titles should also shift left to avoid a right-side abc label.
     """
     fig, axs = uplt.subplots(figsize=(3, 2))
     axs.format(abc=True, title="X" * 100, titleloc="center", abcloc="right")
     title_obj = axs[0]._title_dict["center"]
     original_size = title_obj.get_fontsize()
+    original_x = title_obj.get_position()[0]
     fig.canvas.draw()
-    assert title_obj.get_fontsize() < original_size
+    assert title_obj.get_fontsize() == original_size
+    assert title_obj.get_position()[0] < original_x
     ticks = axs[0].get_xticks()
     assert ticks.size > 0
     xy = np.column_stack([ticks, np.zeros_like(ticks)])