From 3d5ff6fcd19d4ca93f49ab70420b317766657aa9 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Tue, 28 Jun 2022 22:53:59 +0200
Subject: [PATCH] Move the deprecated RendererGTK{3,4}Cairo to a single place.

... and inline _to_context, which is not used anywhere else and can thus
also be deleted at the same time.
---
 lib/matplotlib/backends/backend_cairo.py     | 29 +++++++++-----------
 lib/matplotlib/backends/backend_gtk3cairo.py | 16 +++--------
 lib/matplotlib/backends/backend_gtk4cairo.py | 15 +++-------
 3 files changed, 21 insertions(+), 39 deletions(-)

diff --git a/lib/matplotlib/backends/backend_cairo.py b/lib/matplotlib/backends/backend_cairo.py
index 1b7e58e96efd..2a0b30094701 100644
--- a/lib/matplotlib/backends/backend_cairo.py
+++ b/lib/matplotlib/backends/backend_cairo.py
@@ -38,22 +38,6 @@
 backend_version = cairo.version
 
 
-if cairo.__name__ == "cairocffi":
-    # Convert a pycairo context to a cairocffi one.
-    def _to_context(ctx):
-        if not isinstance(ctx, cairo.Context):
-            ctx = cairo.Context._from_pointer(
-                cairo.ffi.cast(
-                    'cairo_t **',
-                    id(ctx) + object.__basicsize__)[0],
-                incref=True)
-        return ctx
-else:
-    # Pass-through a pycairo context.
-    def _to_context(ctx):
-        return ctx
-
-
 def _append_path(ctx, path, transform, clip=None):
     for points, code in path.iter_segments(
             transform, remove_nans=True, clip=clip):
@@ -547,6 +531,19 @@ def _save(self, fmt, fobj, *, orientation='portrait'):
     print_svgz = functools.partialmethod(_save, "svgz")
 
 
+@_api.deprecated("3.6")
+class _RendererGTKCairo(RendererCairo):
+    def set_context(self, ctx):
+        if (cairo.__name__ == "cairocffi"
+                and not isinstance(ctx, cairo.Context)):
+            ctx = cairo.Context._from_pointer(
+                cairo.ffi.cast(
+                    'cairo_t **',
+                    id(ctx) + object.__basicsize__)[0],
+                incref=True)
+        self.gc.ctx = ctx
+
+
 @_Backend.export
 class _BackendCairo(_Backend):
     FigureCanvas = FigureCanvasCairo
diff --git a/lib/matplotlib/backends/backend_gtk3cairo.py b/lib/matplotlib/backends/backend_gtk3cairo.py
index 0f955956465f..590daf8357dc 100644
--- a/lib/matplotlib/backends/backend_gtk3cairo.py
+++ b/lib/matplotlib/backends/backend_gtk3cairo.py
@@ -1,19 +1,11 @@
 from contextlib import nullcontext
 
-from .. import _api
-from . import backend_cairo, backend_gtk3
-from .backend_gtk3 import Gtk, _BackendGTK3
+from .backend_cairo import (
+    FigureCanvasCairo, _RendererGTKCairo as RendererGTK3Cairo)
+from .backend_gtk3 import Gtk, FigureCanvasGTK3, _BackendGTK3
 
 
-@_api.deprecated("3.6")
-class RendererGTK3Cairo(backend_cairo.RendererCairo):
-    def set_context(self, ctx):
-        self.gc.ctx = backend_cairo._to_context(ctx)
-
-
-class FigureCanvasGTK3Cairo(backend_cairo.FigureCanvasCairo,
-                            backend_gtk3.FigureCanvasGTK3):
-
+class FigureCanvasGTK3Cairo(FigureCanvasCairo, FigureCanvasGTK3):
     def on_draw_event(self, widget, ctx):
         with (self.toolbar._wait_cursor_for_draw_cm() if self.toolbar
               else nullcontext()):
diff --git a/lib/matplotlib/backends/backend_gtk4cairo.py b/lib/matplotlib/backends/backend_gtk4cairo.py
index 09c1e9f90ba8..697884174be3 100644
--- a/lib/matplotlib/backends/backend_gtk4cairo.py
+++ b/lib/matplotlib/backends/backend_gtk4cairo.py
@@ -1,18 +1,11 @@
 from contextlib import nullcontext
 
-from .. import _api
-from . import backend_cairo, backend_gtk4
-from .backend_gtk4 import Gtk, _BackendGTK4
+from .backend_cairo import (
+    FigureCanvasCairo, _RendererGTKCairo as RendererGTK4Cairo)
+from .backend_gtk4 import Gtk, FigureCanvasGTK4, _BackendGTK4
 
 
-@_api.deprecated("3.6")
-class RendererGTK4Cairo(backend_cairo.RendererCairo):
-    def set_context(self, ctx):
-        self.gc.ctx = backend_cairo._to_context(ctx)
-
-
-class FigureCanvasGTK4Cairo(backend_cairo.FigureCanvasCairo,
-                            backend_gtk4.FigureCanvasGTK4):
+class FigureCanvasGTK4Cairo(FigureCanvasCairo, FigureCanvasGTK4):
     _context_is_scaled = True
 
     def on_draw_event(self, widget, ctx):