PGF backend: slightly simplify image drawing

lib/matplotlib/backends/backend_pgf.py

@@ -640,17 +640,13 @@ def draw_image(self, gc, x, y, im, transform=None):
         writeln(self.fh, r"\begin{pgfscope}")
         self._print_pgf_clip(gc)
         f = 1. / self.dpi  # from display coords to inch
+        writeln(self.fh, r"\pgftext[at=\pgfqpoint{%fin}{%fin},left,bottom]{" % (x * f, y * f))
         if transform is not None:
             tr1, tr2, tr3, tr4, tr5, tr6 = transform.frozen().to_values()
-            # scale is already included in the above transform
-            w, h = 1, 1
-            # translation can be merged into this transform (makes it easier)
-            tr5 += x
-            tr6 += y
-            x, y = 0, 0
-            writeln(self.fh, r"\makeatletter\pgfsys@transformcm{%f}{%f}{%f}{%f}{%fin}{%fin}\makeatother" % (tr1, tr2, tr3, tr4, tr5 * f, tr6 * f))
+            w = h = self.dpi  # scale is already included in the transform
+            writeln(self.fh, r"\pgfsys@transformcm{%f}{%f}{%f}{%f}{%fin}{%fin}" % (tr1 * f, tr2 * f, tr3 * f, tr4 * f, tr5 * f, tr6 * f))
         interp = str(transform is None).lower()  # interpolation in PDF reader
-        writeln(self.fh, r"\pgftext[at=\pgfqpoint{%fin}{%fin},left,bottom]{\pgfimage[interpolate=%s,width=%fin,height=%fin]{%s}}" % (x * f, y * f, interp, w * f, h * f, fname_img))
+        writeln(self.fh, r"\pgfimage[interpolate=%s,width=%fin,height=%fin]{%s}}" % (interp, w * f, h * f, fname_img))
         writeln(self.fh, r"\end{pgfscope}")
 
     def draw_tex(self, gc, x, y, s, prop, angle, ismath="TeX!", mtext=None):