From e4c5f65bfd5d81929397e901df89dfc797d85ab5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
Date: Tue, 16 Jan 2024 13:54:56 +0100
Subject: [PATCH] plotters: Adjust to new renderer handling in Matplotlib 3.6
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The handling of the internal renderer objects changed in Matplotlib 3.6, and we
haven't adjusted to the new API. Move the existing logic into a helper function
so we can use it consistently, and try calling the new matplotlib API before
falling back to the old logic.

Fixes #291.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
---
 flent/plotters.py | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/flent/plotters.py b/flent/plotters.py
index 6adcaeca..235e9f15 100644
--- a/flent/plotters.py
+++ b/flent/plotters.py
@@ -952,6 +952,24 @@ def save_pdf(self, filename, data_filename, save_args):
         finally:
             pdf.close()
 
+    def _get_renderer(self):
+
+        # Matplotlib 3.6 reorganised the renderer caching logic and introduced
+        # the _get_renderer() method of the figure class, so try that first
+        try:
+            return self.figure._get_renderer()
+        except AttributeError:
+            pass
+
+        # Older versions of matplotlib cached the renderer in the figure itself,
+        # but it may not exist until after figure is drawn
+        renderer = getattr(self.figure, '_cachedRenderer', None)
+        if not renderer:
+            self.figure.canvas.draw()
+            renderer = getattr(self.figure, '_cachedRenderer', None)
+
+        return renderer
+
     def build_tight_layout(self, artists):
         args = None
         if self.fallback_layout:
@@ -959,7 +977,7 @@ def build_tight_layout(self, artists):
         try:
             self.figure.savefig(io.BytesIO())
 
-            renderer = self.figure._cachedRenderer
+            renderer = self._get_renderer()
             right = x_max = self.figure.get_figwidth() * self.figure.dpi
             top = y_max = self.figure.get_figheight() * self.figure.dpi
             vsp = 0.02 * self.figure.dpi
@@ -1038,15 +1056,9 @@ def size_legends(self, event=None):
            and not self.legend_placement \
            and self.legends:
 
-            # Make sure we have a renderer to get size from
-            renderer = getattr(self.figure, '_cachedRenderer', None)
-            if not renderer:
-                self.figure.canvas.draw()
-                renderer = getattr(self.figure, '_cachedRenderer', None)
-
             try:
                 legend_width = max(
-                    [l.get_window_extent(renderer).width for l in self.legends])
+                    [l.get_window_extent(self._get_renderer()).width for l in self.legends])
             except Exception as e:
                 logger.debug("Error getting legend sizes: %s", e)
                 return