STP1: set up layoutgrids

jklymak · jklymak · commit 977af0a0f3d1 · 2021-05-13T18:47:06.000-07:00
diff --git a/lib/matplotlib/_constrained_layout.py b/lib/matplotlib/_constrained_layout.py
@@ -19,6 +19,8 @@
 
 from matplotlib import _api
 import matplotlib.transforms as mtransforms
+import matplotlib._layoutgrid as layoutgrid
+
 
 _log = logging.getLogger(__name__)
 
@@ -98,6 +100,10 @@ def do_constrained_layout(fig, renderer, h_pad, w_pad,
                            'Possibly did not call parent GridSpec with the'
                            ' "figure" keyword')
 
+    # make layoutgrid tree...
+    _layoutgrids = None
+    _layoutgrids = _make_layoutgrids(fig, _layoutgrids)
+    
     for _ in range(2):
         # do the algorithm twice.  This has to be done because decorations
         # change size after the first re-position (i.e. x/yticklabels get
@@ -128,6 +134,45 @@ def do_constrained_layout(fig, renderer, h_pad, w_pad,
         _reset_margins(fig)
 
 
+def _make_layoutgrids(fig, _layoutgrids):
+
+    if _layoutgrids is None:
+        _layoutgrids = dict()
+    if not hasattr(fig, '_parent'):
+        # top figure
+        _layoutgrids[fig] = layoutgrid.LayoutGrid(parent=None, name='figlb')
+    else:
+        # subfigure
+        gs = fig._subplotspec.get_gridspec()
+        parentlb = _layoutgrids[gs]
+        if parentlb is not None:
+                _layoutgrids[gs] = layoutgrid.LayoutGrid(
+                    parent=parentlb,
+                    name=(parentlb.name + '.' + 'panellb' +
+                          layoutgrid.seq_id()),
+                    parent_inner=True,
+                    nrows=1, ncols=1,
+                    parent_pos=(fig._subplotspec.rowspan,
+                                fig._subplotspec.colspan))
+
+    for sfig in fig.subfigs:
+        _layoutgrids = _make_layoutgrids(sfig, _layoutgrids)
+
+    for ax in fig.axes:
+        if hasattr(ax, 'get_subplotspec'):
+            gs = ax.get_subplotspec().get_gridspec()
+            parent = _layoutgrids[gs.figure]
+            _layoutgrids[gs] = layoutgrid.LayoutGrid(
+                    parent=parent,
+                    parent_inner=True,
+                    name=(parent.name + '.gridspec' +
+                          layoutgrid.seq_id()),
+                    ncols=gs._ncols, nrows=gs._nrows, 
+                    width_ratios=gs.get_width_ratios(),
+                    height_ratios=gs.get_height_ratios())
+    return _layoutgrids
+
+
 def _check_no_collapsed_axes(fig):
     """
     Check that no axes have collapsed to zero size.
