Reduce coupling between _tkagg and _backend_agg modules

Author: mdboom

lib/matplotlib/backends/tkagg.py

@@ -4,6 +4,8 @@
 import six
 from six.moves import tkinter as Tk
 
+import numpy as np
+
 from matplotlib.backends import _tkagg
 
 def blit(photoimage, aggimage, bbox=None, colormode=1):
@@ -13,15 +15,19 @@ def blit(photoimage, aggimage, bbox=None, colormode=1):
         bbox_array = bbox.__array__()
     else:
         bbox_array = None
+    data = np.asarray(aggimage)
     try:
-        tk.call("PyAggImagePhoto", photoimage, id(aggimage), colormode, id(bbox_array))
+        tk.call(
+            "PyAggImagePhoto", photoimage,
+            id(data), colormode, id(bbox_array))
     except Tk.TclError:
         try:
             try:
                 _tkagg.tkinit(tk.interpaddr(), 1)
             except AttributeError:
                 _tkagg.tkinit(id(tk), 0)
-            tk.call("PyAggImagePhoto", photoimage, id(aggimage), colormode, id(bbox_array))
+            tk.call("PyAggImagePhoto", photoimage,
+                    id(data), colormode, id(bbox_array))
         except (ImportError, AttributeError, Tk.TclError):
             raise
 

setupext.py

@@ -852,23 +852,24 @@ def check(self):
             self.__class__.found_external = False
             return str(e) + ' Using local copy.'
 
-    def add_flags(self, ext):
+    def add_flags(self, ext, add_sources=True):
         if self.found_external:
             pkg_config.setup_extension(ext, 'libagg')
         else:
             ext.include_dirs.append('extern/agg24/include')
-            agg_sources = [
-                'agg_bezier_arc.cpp',
-                'agg_curves.cpp',
-                'agg_image_filters.cpp',
-                'agg_trans_affine.cpp',
-                'agg_vcgen_contour.cpp',
-                'agg_vcgen_dash.cpp',
-                'agg_vcgen_stroke.cpp',
-                'agg_vpgen_segmentator.cpp'
-                ]
-            ext.sources.extend(
-                os.path.join('extern', 'agg24', 'src', x) for x in agg_sources)
+            if add_sources:
+                agg_sources = [
+                    'agg_bezier_arc.cpp',
+                    'agg_curves.cpp',
+                    'agg_image_filters.cpp',
+                    'agg_trans_affine.cpp',
+                    'agg_vcgen_contour.cpp',
+                    'agg_vcgen_dash.cpp',
+                    'agg_vcgen_stroke.cpp',
+                    'agg_vpgen_segmentator.cpp'
+                    ]
+                ext.sources.extend(
+                    os.path.join('extern', 'agg24', 'src', x) for x in agg_sources)
 
 
 class FreeType(SetupPackage):
@@ -1298,7 +1299,7 @@ def get_extension(self):
         ext = make_extension('matplotlib.backends._tkagg', sources)
         self.add_flags(ext)
         Numpy().add_flags(ext)
-        LibAgg().add_flags(ext)
+        LibAgg().add_flags(ext, add_sources=False)
         return ext
 
     def query_tcltk(self):

src/_backend_agg_wrapper.cpp

@@ -1,4 +1,25 @@
-#include "_backend_agg_wrapper.h"
+#include "mplutils.h"
+#include "py_converters.h"
+#include "_backend_agg.h"
+
+typedef struct
+{
+    PyObject_HEAD;
+    RendererAgg *x;
+    Py_ssize_t shape[3];
+    Py_ssize_t strides[3];
+    Py_ssize_t suboffsets[3];
+} PyRendererAgg;
+
+typedef struct
+{
+    PyObject_HEAD;
+    BufferRegion *x;
+    Py_ssize_t shape[3];
+    Py_ssize_t strides[3];
+    Py_ssize_t suboffsets[3];
+} PyBufferRegion;
+
 
 /**********************************************************************
  * BufferRegion

src/_backend_agg_wrapper.h

@@ -16,8 +16,6 @@
 #include <cstdio>
 #include <sstream>
 
-#include "agg_basics.h"
-#include "_backend_agg_wrapper.h"
 #include "py_converters.h"
 
 extern "C"
@@ -50,14 +48,14 @@ static int PyAggImagePhoto(ClientData clientdata, Tcl_Interp *interp, int argc,
 {
     Tk_PhotoHandle photo;
     Tk_PhotoImageBlock block;
-    PyObject *aggo;
+    PyObject *bufferobj;
 
     // vars for blitting
     PyObject *bboxo;
 
     size_t aggl, bboxl;
     bool has_bbox;
-    agg::int8u *destbuffer;
+    uint8_t *destbuffer;
     int destx, desty, destwidth, destheight, deststride;
     //unsigned long tmp_ptr;
 
@@ -84,12 +82,17 @@ static int PyAggImagePhoto(ClientData clientdata, Tcl_Interp *interp, int argc,
         Tcl_AppendResult(interp, "error casting pointer", (char *)NULL);
         return TCL_ERROR;
     }
-    aggo = (PyObject *)aggl;
-
-    // TODO: This is really brittle and will break when RendererAgg
-    // comes in multiple flavors
-    RendererAgg *aggRenderer = ((PyRendererAgg *)(aggo))->x;
-    int srcheight = (int)aggRenderer->get_height();
+    bufferobj = (PyObject *)aggl;
+
+    numpy::array_view<uint8_t, 3> buffer;
+    try {
+        buffer = numpy::array_view<uint8_t, 3>(bufferobj);
+    } catch (...) {
+        Tcl_AppendResult(interp, "buffer is of wrong type", (char *)NULL);
+        PyErr_Clear();
+        return TCL_ERROR;
+    }
+    int srcheight = buffer.dim(0);
 
     /* XXX insert aggRenderer type check */
 
@@ -127,13 +130,11 @@ static int PyAggImagePhoto(ClientData clientdata, Tcl_Interp *interp, int argc,
             return TCL_ERROR;
         }
 
-        agg::rendering_buffer destrbuf;
-        destrbuf.attach(destbuffer, destwidth, destheight, deststride);
-        pixfmt destpf(destrbuf);
-        renderer_base destrb(destpf);
-
-        agg::rect_base<int> region(destx, desty, (int)rect.x2, srcheight - (int)rect.y1);
-        destrb.copy_from(aggRenderer->renderingBuffer, &region, -destx, -desty);
+        for (int i = 0; i < destheight; ++i) {
+            memcpy(destbuffer + (deststride * i),
+                   &buffer(i + desty, destx, 0),
+                   deststride);
+        }
     } else {
         has_bbox = false;
         destbuffer = NULL;
@@ -170,10 +171,10 @@ static int PyAggImagePhoto(ClientData clientdata, Tcl_Interp *interp, int argc,
         delete[] destbuffer;
 
     } else {
-        block.width = aggRenderer->get_width();
-        block.height = aggRenderer->get_height();
+        block.width = buffer.dim(1);
+        block.height = buffer.dim(0);
         block.pitch = (int)block.width * nval;
-        block.pixelPtr = aggRenderer->pixBuffer;
+        block.pixelPtr = buffer.data();
 
         /* Clear current contents */
         Tk_PhotoBlank(photo);