matplotlib · tacaswell · Apr 16, 2021 · Apr 15, 2021 · Apr 16, 2021 · Apr 16, 2021
diff --git a/doc/users/next_whats_new/fig_draw_no_output.rst b/doc/users/next_whats_new/fig_draw_no_output.rst
@@ -0,0 +1,10 @@
+Figure now has draw_no_output method
+------------------------------------
+
+Rarely, the user will want to trigger a draw without making output to 
+either the screen or a file.  This is useful for determining the final 
+position of artists on the figure that require a draw, like text artists.
+This could be accomplished via ``fig.canvas.draw()`` but has side effects,
+sometimes requires an open file, and is documented on an object most users 
+do not need to access.  The `.Figure.draw_no_output` is provided to trigger 
+a draw without pushing to the final output, and with fewer side effects.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1584,9 +1584,9 @@ def _draw(renderer): raise Done(renderer)
 
 
 def _no_output_draw(figure):
-    renderer = _get_renderer(figure)
-    with renderer._draw_disabled():
-        figure.draw(renderer)
+    # _no_output_draw was promoted to the figure level, but
+    # keep this here in case someone was calling it...
+    figure.draw_no_output()
 
 
 def _is_non_interactive_terminal_ipython(ip):

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
@@ -29,7 +29,7 @@
 from matplotlib._pylab_helpers import Gcf
 from matplotlib.backend_bases import (
     _Backend, _check_savefig_extra_args, FigureCanvasBase, FigureManagerBase,
-    GraphicsContextBase, RendererBase, _no_output_draw)
+    GraphicsContextBase, RendererBase)
 from matplotlib.backends.backend_mixed import MixedModeRenderer
 from matplotlib.figure import Figure
 from matplotlib.font_manager import findfont, get_font
@@ -2718,7 +2718,7 @@ def print_pdf(self, filename, *,
                 file.close()
 
     def draw(self):
-        _no_output_draw(self.figure)
+        self.figure.draw_no_output()
         return super().draw()
 
 

diff --git a/lib/matplotlib/backends/backend_pgf.py b/lib/matplotlib/backends/backend_pgf.py
@@ -19,7 +19,7 @@
 from matplotlib import _api, cbook, font_manager as fm
 from matplotlib.backend_bases import (
     _Backend, _check_savefig_extra_args, FigureCanvasBase, FigureManagerBase,
-    GraphicsContextBase, RendererBase, _no_output_draw
+    GraphicsContextBase, RendererBase
 )
 from matplotlib.backends.backend_mixed import MixedModeRenderer
 from matplotlib.backends.backend_pdf import (
@@ -889,7 +889,7 @@ def get_renderer(self):
         return RendererPgf(self.figure, None)
 
     def draw(self):
-        _no_output_draw(self.figure)
+        self.figure.draw_no_output()
         return super().draw()
 
 

diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
@@ -23,7 +23,7 @@
 from matplotlib.afm import AFM
 from matplotlib.backend_bases import (
     _Backend, _check_savefig_extra_args, FigureCanvasBase, FigureManagerBase,
-    GraphicsContextBase, RendererBase, _no_output_draw)
+    GraphicsContextBase, RendererBase)
 from matplotlib.cbook import is_writable_file_like, file_requires_unicode
 from matplotlib.font_manager import get_font
 from matplotlib.ft2font import LOAD_NO_HINTING, LOAD_NO_SCALE
@@ -1112,7 +1112,7 @@ def _print_figure_tex(
             _move_path_to_path_or_stream(tmpfile, outfile)
 
     def draw(self):
-        _no_output_draw(self.figure)
+        self.figure.draw_no_output()
         return super().draw()
 
 

diff --git a/lib/matplotlib/backends/backend_svg.py b/lib/matplotlib/backends/backend_svg.py
@@ -17,7 +17,7 @@
 from matplotlib import _api, cbook
 from matplotlib.backend_bases import (
      _Backend, _check_savefig_extra_args, FigureCanvasBase, FigureManagerBase,
-     RendererBase, _no_output_draw)
+     RendererBase)
 from matplotlib.backends.backend_mixed import MixedModeRenderer
 from matplotlib.colors import rgb2hex
 from matplotlib.dates import UTC
@@ -1343,7 +1343,7 @@ def get_default_filetype(self):
         return 'svg'
 
     def draw(self):
-        _no_output_draw(self.figure)
+        self.figure.draw_no_output()
         return super().draw()
 
 

diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -26,7 +26,7 @@
 from matplotlib.artist import (
     Artist, allow_rasterization, _finalize_rasterization)
 from matplotlib.backend_bases import (
-    FigureCanvasBase, NonGuiException, MouseButton)
+    FigureCanvasBase, NonGuiException, MouseButton, _get_renderer)
 import matplotlib._api as _api
 import matplotlib.cbook as cbook
 import matplotlib.colorbar as cbar
@@ -2739,6 +2739,15 @@ def draw(self, renderer):
 
         self.canvas.draw_event(renderer)
 
+    def draw_no_output(self):
+        """
+        Draw the figure with no output.  Useful to get the final size of
+        artists that require a draw before their size is known (e.g. text).
+        """
+        renderer = _get_renderer(self)
+        with renderer._draw_disabled():
+            self.draw(renderer)
+
     def draw_artist(self, a):
         """
         Draw `.Artist` *a* only.
@@ -3015,7 +3024,6 @@ def execute_constrained_layout(self, renderer=None):
         """
 
         from matplotlib._constrained_layout import do_constrained_layout
-        from matplotlib.tight_layout import get_renderer
 
         _log.debug('Executing constrainedlayout')
         if self._layoutgrid is None:
@@ -3033,7 +3041,7 @@ def execute_constrained_layout(self, renderer=None):
         w_pad = w_pad / width
         h_pad = h_pad / height
         if renderer is None:
-            renderer = get_renderer(fig)
+            renderer = _get_renderer(fig)
         do_constrained_layout(fig, renderer, h_pad, w_pad, hspace, wspace)
 
     def tight_layout(self, *, pad=1.08, h_pad=None, w_pad=None, rect=None):
@@ -3063,15 +3071,15 @@ def tight_layout(self, *, pad=1.08, h_pad=None, w_pad=None, rect=None):
         """
 
         from .tight_layout import (
-            get_renderer, get_subplotspec_list, get_tight_layout_figure)
+            get_subplotspec_list, get_tight_layout_figure)
         from contextlib import suppress
         subplotspec_list = get_subplotspec_list(self.axes)
         if None in subplotspec_list:
             _api.warn_external("This figure includes Axes that are not "
                                "compatible with tight_layout, so results "
                                "might be incorrect.")
 
-        renderer = get_renderer(self)
+        renderer = _get_renderer(self)
         ctx = (renderer._draw_disabled()
                if hasattr(renderer, '_draw_disabled')
                else suppress())

diff --git a/lib/matplotlib/tests/test_constrainedlayout.py b/lib/matplotlib/tests/test_constrainedlayout.py
@@ -134,7 +134,7 @@ def test_constrained_layout7():
         for gs in gsl:
             fig.add_subplot(gs)
         # need to trigger a draw to get warning
-        fig.draw(fig.canvas.get_renderer())
+        fig.draw_no_output()
 
 
 @image_comparison(['constrained_layout8.png'])
@@ -327,7 +327,7 @@ def test_constrained_layout18():
     ax2 = ax.twinx()
     example_plot(ax)
     example_plot(ax2, fontsize=24)
-    fig.canvas.draw()
+    fig.draw_no_output()
     assert all(ax.get_position().extents == ax2.get_position().extents)
 
 
@@ -339,7 +339,7 @@ def test_constrained_layout19():
     example_plot(ax2, fontsize=24)
     ax2.set_title('')
     ax.set_title('')
-    fig.canvas.draw()
+    fig.draw_no_output()
     assert all(ax.get_position().extents == ax2.get_position().extents)
 
 
@@ -359,11 +359,11 @@ def test_constrained_layout21():
     fig, ax = plt.subplots(constrained_layout=True)
 
     fig.suptitle("Suptitle0")
-    fig.canvas.draw()
+    fig.draw_no_output()
     extents0 = np.copy(ax.get_position().extents)
 
     fig.suptitle("Suptitle1")
-    fig.canvas.draw()
+    fig.draw_no_output()
     extents1 = np.copy(ax.get_position().extents)
 
     np.testing.assert_allclose(extents0, extents1)
@@ -373,11 +373,11 @@ def test_constrained_layout22():
     """#11035: suptitle should not be include in CL if manually positioned"""
     fig, ax = plt.subplots(constrained_layout=True)
 
-    fig.canvas.draw()
+    fig.draw_no_output()
     extents0 = np.copy(ax.get_position().extents)
 
     fig.suptitle("Suptitle", y=0.5)
-    fig.canvas.draw()
+    fig.draw_no_output()
     extents1 = np.copy(ax.get_position().extents)
 
     np.testing.assert_allclose(extents0, extents1)
@@ -425,7 +425,7 @@ def test_hidden_axes():
     # (as does a gridspec slot that is empty)
     fig, axs = plt.subplots(2, 2, constrained_layout=True)
     axs[0, 1].set_visible(False)
-    fig.canvas.draw()
+    fig.draw_no_output()
     extents1 = np.copy(axs[0, 0].get_position().extents)
 
     np.testing.assert_allclose(
@@ -451,7 +451,7 @@ def test_colorbar_align():
         fig.set_constrained_layout_pads(w_pad=4 / 72, h_pad=4 / 72, hspace=0.1,
                                         wspace=0.1)
 
-        fig.canvas.draw()
+        fig.draw_no_output()
         if location in ['left', 'right']:
             np.testing.assert_allclose(cbs[0].ax.get_position().x0,
                                        cbs[2].ax.get_position().x0)
@@ -493,15 +493,15 @@ def test_colorbars_no_overlapH():
 def test_manually_set_position():
     fig, axs = plt.subplots(1, 2, constrained_layout=True)
     axs[0].set_position([0.2, 0.2, 0.3, 0.3])
-    fig.canvas.draw()
+    fig.draw_no_output()
     pp = axs[0].get_position()
     np.testing.assert_allclose(pp, [[0.2, 0.2], [0.5, 0.5]])
 
     fig, axs = plt.subplots(1, 2, constrained_layout=True)
     axs[0].set_position([0.2, 0.2, 0.3, 0.3])
     pc = axs[0].pcolormesh(np.random.rand(20, 20))
     fig.colorbar(pc, ax=axs[0])
-    fig.canvas.draw()
+    fig.draw_no_output()
     pp = axs[0].get_position()
     np.testing.assert_allclose(pp, [[0.2, 0.2], [0.44, 0.5]])
 
@@ -546,7 +546,7 @@ def test_align_labels():
 
     fig.align_ylabels(axs=(ax3, ax1, ax2))
 
-    fig.canvas.draw()
+    fig.draw_no_output()
     after_align = [ax1.yaxis.label.get_window_extent(),
                    ax2.yaxis.label.get_window_extent(),
                    ax3.yaxis.label.get_window_extent()]

diff --git a/lib/matplotlib/tests/test_figure.py b/lib/matplotlib/tests/test_figure.py
@@ -415,11 +415,11 @@ def test_autofmt_xdate(which):
 @pytest.mark.style('default')
 def test_change_dpi():
     fig = plt.figure(figsize=(4, 4))
-    fig.canvas.draw()
+    fig.draw_no_output()
     assert fig.canvas.renderer.height == 400
     assert fig.canvas.renderer.width == 400
     fig.dpi = 50
-    fig.canvas.draw()
+    fig.draw_no_output()
     assert fig.canvas.renderer.height == 200
     assert fig.canvas.renderer.width == 200