Agg backend shouldn't do its own image interp

lib/matplotlib/backends/backend_agg.py

@@ -321,7 +321,7 @@ def option_scale_image(self):
         """
         agg backend support arbitrary scaling of image.
         """
-        return True
+        return False
 
     def restore_region(self, region, bbox=None, xy=None):
         """
@@ -389,28 +389,22 @@ def post_processing(image, dpi):
         # For agg_filter to work, the rendere's method need
         # to overridden in the class. See draw_markers, and draw_path_collections
 
-        from matplotlib._image import fromarray
-
         width, height = int(self.width), int(self.height)
 
         buffer, bounds = self.tostring_rgba_minimized()
 
         l, b, w, h = bounds
 
-
         self._renderer = self._filter_renderers.pop()
         self._update_methods()
 
         if w > 0 and h > 0:
             img = np.fromstring(buffer, np.uint8)
             img, ox, oy = post_processing(img.reshape((h, w, 4)) / 255.,
                                           self.dpi)
-            image = fromarray(img, 1)
-
             gc = self.new_gc()
-            self._renderer.draw_image(gc,
-                                      l+ox, height - b - h +oy,
-                                      image)
+            self._renderer.draw_image(
+                gc, l + ox, height - b - h + oy, img)
 
 
 def new_figure_manager(num, *args, **kwargs):

src/_backend_agg.h

@@ -158,11 +158,7 @@ class RendererAgg
     void draw_image(GCAgg &gc,
                     double x,
                     double y,
-                    ImageArray &image,
-                    double w,
-                    double h,
-                    agg::trans_affine trans,
-                    bool resize);
+                    ImageArray &image);
 
     template <class PathGenerator,
               class TransformArray,
@@ -832,11 +828,7 @@ template <class ImageArray>
 inline void RendererAgg::draw_image(GCAgg &gc,
                                     double x,
                                     double y,
-                                    ImageArray &image,
-                                    double w,
-                                    double h,
-                                    agg::trans_affine trans,
-                                    bool resize)
+                                    ImageArray &image)
 {
     double alpha = gc.alpha;
 
@@ -850,21 +842,11 @@ inline void RendererAgg::draw_image(GCAgg &gc,
         image.data(), (unsigned)image.dim(1), (unsigned)image.dim(0), -(int)image.dim(1) * 4);
     pixfmt pixf(buffer);
 
-    if (resize | has_clippath) {
+    if (has_clippath) {
         agg::trans_affine mtx;
         agg::path_storage rect;
 
-        if (resize) {
-            mtx *= agg::trans_affine_scaling(1, -1);
-            mtx *= agg::trans_affine_translation(0, image.dim(0));
-            mtx *= agg::trans_affine_scaling(w / (image.dim(1)), h / (image.dim(0)));
-            mtx *= agg::trans_affine_translation(x, y);
-            mtx *= trans;
-            mtx *= agg::trans_affine_scaling(1.0, -1.0);
-            mtx *= agg::trans_affine_translation(0.0, (double)height);
-        } else {
-            mtx *= agg::trans_affine_translation((int)x, (int)(height - (y + image.dim(0))));
-        }
+        mtx *= agg::trans_affine_translation((int)x, (int)(height - (y + image.dim(0))));
 
         rect.move_to(0, 0);
         rect.line_to(image.dim(1), 0);
@@ -891,30 +873,17 @@ inline void RendererAgg::draw_image(GCAgg &gc,
         span_conv_alpha conv_alpha(alpha);
         span_conv spans(image_span_generator, conv_alpha);
 
-        if (has_clippath) {
-            typedef agg::pixfmt_amask_adaptor<pixfmt, alpha_mask_type> pixfmt_amask_type;
-            typedef agg::renderer_base<pixfmt_amask_type> amask_ren_type;
-            typedef agg::renderer_scanline_aa<amask_ren_type, color_span_alloc_type, span_conv>
+        typedef agg::pixfmt_amask_adaptor<pixfmt, alpha_mask_type> pixfmt_amask_type;
+        typedef agg::renderer_base<pixfmt_amask_type> amask_ren_type;
+        typedef agg::renderer_scanline_aa<amask_ren_type, color_span_alloc_type, span_conv>
             renderer_type_alpha;
 
-            pixfmt_amask_type pfa(pixFmt, alphaMask);
-            amask_ren_type r(pfa);
-            renderer_type_alpha ri(r, sa, spans);
-
-            theRasterizer.add_path(rect2);
-            agg::render_scanlines(theRasterizer, scanlineAlphaMask, ri);
-        } else {
-            typedef agg::renderer_base<pixfmt> ren_type;
-            typedef agg::renderer_scanline_aa<ren_type, color_span_alloc_type, span_conv>
-            renderer_type;
-
-            ren_type r(pixFmt);
-            renderer_type ri(r, sa, spans);
-
-            theRasterizer.add_path(rect2);
-            agg::render_scanlines(theRasterizer, slineP8, ri);
-        }
+        pixfmt_amask_type pfa(pixFmt, alphaMask);
+        amask_ren_type r(pfa);
+        renderer_type_alpha ri(r, sa, spans);
 
+        theRasterizer.add_path(rect2);
+        agg::render_scanlines(theRasterizer, scanlineAlphaMask, ri);
     } else {
         set_clipbox(gc.cliprect, rendererBase);
         rendererBase.blend_from(

src/_backend_agg_wrapper.cpp

@@ -284,34 +284,22 @@ static PyObject *PyRendererAgg_draw_image(PyRendererAgg *self, PyObject *args, P
     double x;
     double y;
     numpy::array_view<agg::int8u, 3> image;
-    double w = 0;
-    double h = 0;
-    agg::trans_affine trans;
-    bool resize = false;
 
     if (!PyArg_ParseTuple(args,
-                          "O&ddO&|ddO&:draw_image",
+                          "O&ddO&:draw_image",
                           &convert_gcagg,
                           &gc,
                           &x,
                           &y,
                           &image.converter_contiguous,
-                          &image,
-                          &w,
-                          &h,
-                          &convert_trans_affine,
-                          &trans)) {
+                          &image)) {
         return NULL;
     }
 
-    if (PyTuple_Size(args) == 4) {
-        x = mpl_round(x);
-        y = mpl_round(y);
-    } else {
-        resize = true;
-    }
+    x = mpl_round(x);
+    y = mpl_round(y);
 
-    CALL_CPP("draw_image", (self->x->draw_image(gc, x, y, image, w, h, trans, resize)));
+    CALL_CPP("draw_image", (self->x->draw_image(gc, x, y, image)));
 
     Py_RETURN_NONE;
 }