Merge pull request #11735 from anntzer/aggbufferrgba

QuLogic · web-flow · commit 529eb3d41245 · 2018-12-26T19:19:13.000-05:00
Change {FigureCanvasAgg,RendererAgg}.buffer_rgba to return a memoryview.
diff --git a/doc/api/next_api_changes/2018-07-22-AL.rst b/doc/api/next_api_changes/2018-07-22-AL.rst
@@ -0,0 +1,7 @@
+`FigureCanvasAgg.buffer_rgba` and `RendererAgg.buffer_rgba` now return a memoryview
+```````````````````````````````````````````````````````````````````````````````````
+
+The ``buffer_rgba`` method now allows direct access to the renderer's
+underlying buffer (as a ``(m, n, 4)``-shape memoryview) rather than copying the
+data to a new bytestring.  This is consistent with the behavior on Py2, where a
+buffer object was returned.
diff --git a/examples/misc/agg_buffer_to_array.py b/examples/misc/agg_buffer_to_array.py
@@ -15,7 +15,7 @@
 fig.canvas.draw()
 
 # grab the pixel buffer and dump it into a numpy array
-X = np.array(fig.canvas.renderer._renderer)
+X = np.array(fig.canvas.renderer.buffer_rgba())
 
 # now display the array X as an Axes in a new figure
 fig2 = plt.figure()
diff --git a/lib/matplotlib/backends/backend_agg.py b/lib/matplotlib/backends/backend_agg.py
@@ -256,14 +256,14 @@ def points_to_pixels(self, points):
         # docstring inherited
         return points * self.dpi / 72
 
-    def tostring_rgb(self):
-        return self._renderer.tostring_rgb()
+    def buffer_rgba(self):
+        return memoryview(self._renderer)
 
     def tostring_argb(self):
-        return self._renderer.tostring_argb()
+        return np.asarray(self._renderer).take([3, 0, 1, 2], axis=2).tobytes()
 
-    def buffer_rgba(self):
-        return self._renderer.buffer_rgba()
+    def tostring_rgb(self):
+        return np.asarray(self._renderer).take([0, 1, 2], axis=2).tobytes()
 
     def clear(self):
         self._renderer.clear()
@@ -409,40 +409,39 @@ def get_renderer(self, cleared=False):
         return self.renderer
 
     def tostring_rgb(self):
-        '''Get the image as an RGB byte string.
+        """Get the image as an RGB byte string.
 
         `draw` must be called at least once before this function will work and
         to update the renderer for any subsequent changes to the Figure.
 
         Returns
         -------
         bytes
-        '''
+        """
         return self.renderer.tostring_rgb()
 
     def tostring_argb(self):
-        '''Get the image as an ARGB byte string
+        """Get the image as an ARGB byte string.
 
         `draw` must be called at least once before this function will work and
         to update the renderer for any subsequent changes to the Figure.
 
         Returns
         -------
         bytes
-
-        '''
+        """
         return self.renderer.tostring_argb()
 
     def buffer_rgba(self):
-        '''Get the image as an RGBA byte string.
+        """Get the image as a memoryview to the renderer's buffer.
 
         `draw` must be called at least once before this function will work and
         to update the renderer for any subsequent changes to the Figure.
 
         Returns
         -------
-        bytes
-        '''
+        memoryview
+        """
         return self.renderer.buffer_rgba()
 
     def print_raw(self, filename_or_obj, *args, **kwargs):
diff --git a/src/_backend_agg.cpp b/src/_backend_agg.cpp
@@ -156,29 +156,6 @@ bool RendererAgg::render_clippath(py::PathIterator &clippath,
     return has_clippath;
 }
 
-void RendererAgg::tostring_rgb(uint8_t *buf)
-{
-    // "Return the rendered buffer as an RGB string"
-
-    int row_len = width * 3;
-
-    agg::rendering_buffer renderingBufferTmp;
-    renderingBufferTmp.attach(buf, width, height, row_len);
-
-    agg::color_conv(&renderingBufferTmp, &renderingBuffer, agg::color_conv_rgba32_to_rgb24());
-}
-
-void RendererAgg::tostring_argb(uint8_t *buf)
-{
-    //"Return the rendered buffer as an RGB string";
-
-    int row_len = width * 4;
-
-    agg::rendering_buffer renderingBufferTmp;
-    renderingBufferTmp.attach(buf, width, height, row_len);
-    agg::color_conv(&renderingBufferTmp, &renderingBuffer, agg::color_conv_rgba32_to_argb32());
-}
-
 agg::rect_i RendererAgg::get_content_extents()
 {
     agg::rect_i r(width, height, 0, 0);
diff --git a/src/_backend_agg.h b/src/_backend_agg.h
@@ -203,8 +203,6 @@ class RendererAgg
                                 ColorArray &colors,
                                 agg::trans_affine &trans);
 
-    void tostring_rgb(uint8_t *buf);
-    void tostring_argb(uint8_t *buf);
     agg::rect_i get_content_extents();
     void clear();
 
diff --git a/src/_backend_agg_wrapper.cpp b/src/_backend_agg_wrapper.cpp
@@ -525,38 +525,6 @@ PyRendererAgg_draw_gouraud_triangles(PyRendererAgg *self, PyObject *args, PyObje
     Py_RETURN_NONE;
 }
 
-static PyObject *PyRendererAgg_tostring_rgb(PyRendererAgg *self, PyObject *args, PyObject *kwds)
-{
-    PyObject *buffobj = NULL;
-
-    buffobj = PyBytes_FromStringAndSize(NULL, self->x->get_width() * self->x->get_height() * 3);
-    if (buffobj == NULL) {
-        return NULL;
-    }
-
-    CALL_CPP_CLEANUP("tostring_rgb",
-                     (self->x->tostring_rgb((uint8_t *)PyBytes_AS_STRING(buffobj))),
-                     Py_DECREF(buffobj));
-
-    return buffobj;
-}
-
-static PyObject *PyRendererAgg_tostring_argb(PyRendererAgg *self, PyObject *args, PyObject *kwds)
-{
-    PyObject *buffobj = NULL;
-
-    buffobj = PyBytes_FromStringAndSize(NULL, self->x->get_width() * self->x->get_height() * 4);
-    if (buffobj == NULL) {
-        return NULL;
-    }
-
-    CALL_CPP_CLEANUP("tostring_argb",
-                     (self->x->tostring_argb((uint8_t *)PyBytes_AS_STRING(buffobj))),
-                     Py_DECREF(buffobj));
-
-    return buffobj;
-}
-
 static PyObject *
 PyRendererAgg_get_content_extents(PyRendererAgg *self, PyObject *args, PyObject *kwds)
 {
@@ -664,8 +632,6 @@ static PyTypeObject *PyRendererAgg_init_type(PyObject *m, PyTypeObject *type)
         {"draw_gouraud_triangle", (PyCFunction)PyRendererAgg_draw_gouraud_triangle, METH_VARARGS, NULL},
         {"draw_gouraud_triangles", (PyCFunction)PyRendererAgg_draw_gouraud_triangles, METH_VARARGS, NULL},
 
-        {"tostring_rgb", (PyCFunction)PyRendererAgg_tostring_rgb, METH_NOARGS, NULL},
-        {"tostring_argb", (PyCFunction)PyRendererAgg_tostring_argb, METH_NOARGS, 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},
