Merge pull request matplotlib#869 from mdboom/faster_nearest

Faster "direct" interpolation

Author: mdboom

src/_image.cpp

@@ -439,11 +439,15 @@ Image::resize(const Py::Tuple& args, const Py::Dict& kwargs)
 
     case NEAREST:
     {
-        typedef agg::span_image_filter_rgba_nn<img_accessor_type, interpolator_type> span_gen_type;
-        typedef agg::renderer_scanline_aa<renderer_base, span_alloc_type, span_gen_type> renderer_type;
-        span_gen_type sg(ia, interpolator);
-        renderer_type ri(rb, sa, sg);
-        agg::render_scanlines(ras, sl, ri);
+        if (colsIn == numcols && rowsIn == numrows) {
+            memcpy(bufferOut, bufferIn, colsIn * rowsIn * 4);
+        } else {
+            typedef agg::span_image_filter_rgba_nn<img_accessor_type, interpolator_type> span_gen_type;
+            typedef agg::renderer_scanline_aa<renderer_base, span_alloc_type, span_gen_type> renderer_type;
+            span_gen_type sg(ia, interpolator);
+            renderer_type ri(rb, sa, sg);
+            agg::render_scanlines(ras, sl, ri);
+        }
     }
     break;