Kill the C-level RendererAgg.buffer_rgba, which returns a copy.

anntzer · anntzer · commit 71594e178b2a · 2019-07-30T12:29:07.000+02:00
Not to be confused with the Python-level buffer_rgba, which returns
a memoryview, which we can also use to save a copy when saving to
jpeg/tiff.

Also remove some dpi-settings, which occur after drawing and are thus
pointless anyways.
diff --git a/lib/matplotlib/backends/backend_agg.py b/lib/matplotlib/backends/backend_agg.py
@@ -449,9 +449,8 @@ def buffer_rgba(self):
     def print_raw(self, filename_or_obj, *args, **kwargs):
         FigureCanvasAgg.draw(self)
         renderer = self.get_renderer()
-        with cbook._setattr_cm(renderer, dpi=self.figure.dpi), \
-                cbook.open_file_cm(filename_or_obj, "wb") as fh:
-            fh.write(renderer._renderer.buffer_rgba())
+        with cbook.open_file_cm(filename_or_obj, "wb") as fh:
+            fh.write(renderer.buffer_rgba())
 
     print_rgba = print_raw
 
@@ -516,10 +515,10 @@ def print_png(self, filename_or_obj, *args,
             **metadata,
         }
 
+        FigureCanvasAgg.draw(self)
         if pil_kwargs is not None:
             from PIL import Image
             from PIL.PngImagePlugin import PngInfo
-            buf, size = self.print_to_buffer()
             # Only use the metadata kwarg if pnginfo is not set, because the
             # semantics of duplicate keys in pnginfo is unclear.
             if "pnginfo" not in pil_kwargs:
@@ -528,23 +527,20 @@ def print_png(self, filename_or_obj, *args,
                     pnginfo.add_text(k, v)
                 pil_kwargs["pnginfo"] = pnginfo
             pil_kwargs.setdefault("dpi", (self.figure.dpi, self.figure.dpi))
-            (Image.frombuffer("RGBA", size, buf, "raw", "RGBA", 0, 1)
+            (Image.fromarray(np.asarray(self.buffer_rgba()))
              .save(filename_or_obj, format="png", **pil_kwargs))
 
         else:
-            FigureCanvasAgg.draw(self)
             renderer = self.get_renderer()
-            with cbook._setattr_cm(renderer, dpi=self.figure.dpi), \
-                    cbook.open_file_cm(filename_or_obj, "wb") as fh:
+            with cbook.open_file_cm(filename_or_obj, "wb") as fh:
                 _png.write_png(renderer._renderer, fh,
                                self.figure.dpi, metadata=metadata)
 
     def print_to_buffer(self):
         FigureCanvasAgg.draw(self)
         renderer = self.get_renderer()
-        with cbook._setattr_cm(renderer, dpi=self.figure.dpi):
-            return (renderer._renderer.buffer_rgba(),
-                    (int(renderer.width), int(renderer.height)))
+        return (bytes(renderer.buffer_rgba()),
+                (int(renderer.width), int(renderer.height)))
 
     if _has_pil:
 
@@ -585,15 +581,15 @@ def print_jpg(self, filename_or_obj, *args, dryrun=False,
                 `PIL.Image.save` when saving the figure.  These take precedence
                 over *quality*, *optimize* and *progressive*.
             """
-            buf, size = self.print_to_buffer()
+            FigureCanvasAgg.draw(self)
             if dryrun:
                 return
             # The image is "pasted" onto a white background image to safely
             # handle any transparency
-            image = Image.frombuffer('RGBA', size, buf, 'raw', 'RGBA', 0, 1)
+            image = Image.fromarray(np.asarray(self.buffer_rgba()))
             rgba = mcolors.to_rgba(rcParams['savefig.facecolor'])
             color = tuple([int(x * 255) for x in rgba[:3]])
-            background = Image.new('RGB', size, color)
+            background = Image.new('RGB', image.size, color)
             background.paste(image, image)
             if pil_kwargs is None:
                 pil_kwargs = {}
@@ -610,14 +606,14 @@ def print_jpg(self, filename_or_obj, *args, dryrun=False,
         @cbook._delete_parameter("3.2", "dryrun")
         def print_tif(self, filename_or_obj, *args, dryrun=False,
                       pil_kwargs=None, **kwargs):
-            buf, size = self.print_to_buffer()
+            FigureCanvasAgg.draw(self)
             if dryrun:
                 return
-            image = Image.frombuffer('RGBA', size, buf, 'raw', 'RGBA', 0, 1)
             if pil_kwargs is None:
                 pil_kwargs = {}
             pil_kwargs.setdefault("dpi", (self.figure.dpi, self.figure.dpi))
-            return image.save(filename_or_obj, format='tiff', **pil_kwargs)
+            return (Image.fromarray(np.asarray(self.buffer_rgba()))
+                    .save(filename_or_obj, format='tiff', **pil_kwargs))
 
         print_tiff = print_tif
 
diff --git a/src/_backend_agg_wrapper.cpp b/src/_backend_agg_wrapper.cpp
@@ -536,12 +536,6 @@ PyRendererAgg_get_content_extents(PyRendererAgg *self, PyObject *args, PyObject
         "iiii", extents.x1, extents.y1, extents.x2 - extents.x1, extents.y2 - extents.y1);
 }
 
-static PyObject *PyRendererAgg_buffer_rgba(PyRendererAgg *self, PyObject *args, PyObject *kwds)
-{
-    return PyBytes_FromStringAndSize((const char *)self->x->pixBuffer,
-                                     self->x->get_width() * self->x->get_height() * 4);
-}
-
 int PyRendererAgg_get_buffer(PyRendererAgg *self, Py_buffer *buf, int flags)
 {
     Py_INCREF(self);
@@ -633,7 +627,6 @@ static PyTypeObject *PyRendererAgg_init_type(PyObject *m, PyTypeObject *type)
         {"draw_gouraud_triangles", (PyCFunction)PyRendererAgg_draw_gouraud_triangles, METH_VARARGS, NULL},
 
         {"get_content_extents", (PyCFunction)PyRendererAgg_get_content_extents, METH_NOARGS, NULL},
-        {"buffer_rgba", (PyCFunction)PyRendererAgg_buffer_rgba, METH_NOARGS, NULL},
         {"clear", (PyCFunction)PyRendererAgg_clear, METH_NOARGS, NULL},
 
         {"copy_from_bbox", (PyCFunction)PyRendererAgg_copy_from_bbox, METH_VARARGS, NULL},
