Add UltraLayout: Advanced constraint-based positioning for non-orthogonal subplot arrangements

ultraplot/axes/base.py

@@ -2792,6 +2792,79 @@ def _reposition_subplot(self):
             self.update_params()
             setter(self.figbox)  # equivalent to above
 
+        # In UltraLayout, place panels relative to their parent axes, not the grid.
+        if (
+            self._panel_parent
+            and self._panel_side
+            and self.figure.gridspec._use_ultra_layout
+        ):
+            gs = self.get_subplotspec().get_gridspec()
+            figwidth, figheight = self.figure.get_size_inches()
+            ss = self.get_subplotspec().get_topmost_subplotspec()
+            row1, row2, col1, col2 = ss._get_rows_columns(ncols=gs.ncols_total)
+            side = self._panel_side
+            parent_bbox = self._panel_parent.get_position()
+            panels = list(self._panel_parent._panel_dict.get(side, ()))
+            anchor_ax = self._panel_parent
+            if self in panels:
+                idx = panels.index(self)
+                if idx > 0:
+                    anchor_ax = panels[idx - 1]
+            elif panels:
+                anchor_ax = panels[-1]
+            anchor_bbox = anchor_ax.get_position()
+            anchor_ss = anchor_ax.get_subplotspec().get_topmost_subplotspec()
+            a_row1, a_row2, a_col1, a_col2 = anchor_ss._get_rows_columns(
+                ncols=gs.ncols_total
+            )
+
+            if side in ("right", "left"):
+                boundary = None
+                width = sum(gs._wratios_total[col1 : col2 + 1]) / figwidth
+                if a_col2 < col1:
+                    boundary = a_col2
+                elif col2 < a_col1:
+                    boundary = col2
+                # Fall back to an interface adjacent to this panel
+                boundary = min(
+                    max(
+                        _not_none(boundary, a_col2 if side == "right" else col2),
+                        0,
+                    ),
+                    len(gs.wspace_total) - 1,
+                )
+                pad = gs.wspace_total[boundary] / figwidth
+                if side == "right":
+                    x0 = anchor_bbox.x1 + pad
+                else:
+                    x0 = anchor_bbox.x0 - pad - width
+                bbox = mtransforms.Bbox.from_bounds(
+                    x0, parent_bbox.y0, width, parent_bbox.height
+                )
+            else:
+                boundary = None
+                height = sum(gs._hratios_total[row1 : row2 + 1]) / figheight
+                if a_row2 < row1:
+                    boundary = a_row2
+                elif row2 < a_row1:
+                    boundary = row2
+                boundary = min(
+                    max(
+                        _not_none(boundary, a_row2 if side == "top" else row2),
+                        0,
+                    ),
+                    len(gs.hspace_total) - 1,
+                )
+                pad = gs.hspace_total[boundary] / figheight
+                if side == "top":
+                    y0 = anchor_bbox.y1 + pad
+                else:
+                    y0 = anchor_bbox.y0 - pad - height
+                bbox = mtransforms.Bbox.from_bounds(
+                    parent_bbox.x0, y0, parent_bbox.width, height
+                )
+            setter(bbox)
+
     def _update_abc(self, **kwargs):
         """
         Update the a-b-c label.

ultraplot/axes/plot.py

@@ -3187,9 +3187,9 @@ def _parse_level_lim(
         for z in zs:
             if z is None:  # e.g. empty scatter color
                 continue
+            z = inputs._to_numpy_array(z)
             if z.ndim > 2:  # e.g. imshow data
                 continue
-            z = inputs._to_numpy_array(z)
             if inbounds and x is not None and y is not None:  # ignore if None coords
                 z = self._inbounds_vlim(x, y, z, to_centers=to_centers)
             imin, imax = inputs._safe_range(z, pmin, pmax)

ultraplot/figure.py

@@ -661,7 +661,9 @@ def __init__(
             )
         self._refnum = refnum
         self._refaspect = refaspect
-        self._refaspect_default = 1  # updated for imshow and geographic plots
+        # Default to a square reference aspect; auto_layout will update this when an
+        # explicit aspect is detected (e.g., imshow, geographic plots).
+        self._refaspect_default = 1
         self._refwidth = units(refwidth, "in")
         self._refheight = units(refheight, "in")
         self._figwidth = figwidth = units(figwidth, "in")
@@ -1841,7 +1843,7 @@ def _axes_dict(naxs, input, kw=False, default=None):
         # Create or update the gridspec and add subplots with subplotspecs
         # NOTE: The gridspec is added to the figure when we pass the subplotspec
         if gs is None:
-            gs = pgridspec.GridSpec(*array.shape, **gridspec_kw)
+            gs = pgridspec.GridSpec(*array.shape, layout_array=array, **gridspec_kw)
         else:
             gs.update(**gridspec_kw)
         axs = naxs * [None]  # list of axes
@@ -2399,6 +2401,16 @@ def _align_content():  # noqa: E306
             gs._auto_layout_tight(renderer)
         _align_content()
 
+        # Finalize figure size using the latest spaces. If the size changes, update
+        # layout one more time to minimize surrounding whitespace with the new bounds.
+        figsize = gs._update_figsize()
+        eps = 0.01
+        if self._refwidth is not None or self._refheight is not None:
+            eps = 0
+        if not self._is_same_size(figsize, eps=eps):
+            # Use zero tolerance so sub-inch adjustments apply when ref sizes are set.
+            self.set_size_inches(figsize, internal=True, eps=0)
+
     @warnings._rename_kwargs(
         "0.10.0", mathtext_fallback="uplt.rc.mathtext_fallback = {}"
     )