[MRG] API: expose screenshot params in save_image()

CHANGES

@@ -24,6 +24,8 @@ Version 0.7
   to manually install ``ffmpeg``. ``imageio`` has been added as an optional
   dependency which can be installed with
   ``$ pip install pysurfer[save_movie]``.
+- ``Brain.save_image`` now has the option to save with alpha channel and
+  antialiasing.
 
 Version 0.6
 -----------

surfer/tests/test_viz.py

@@ -57,6 +57,7 @@ def test_image():
 
     brain = Brain(*std_args, size=100)
     brain.save_image(tmp_name)
+    brain.save_image(tmp_name, 'rgba', True)
     brain.save_montage(tmp_name, ['l', 'v', 'm'], orientation='v')
     brain.save_montage(tmp_name, ['l', 'v', 'm'], orientation='h')
     brain.save_montage(tmp_name, [['l', 'v'], ['m', 'f']])

surfer/viz.py

@@ -2010,7 +2010,7 @@ def save_single_image(self, filename, row=-1, col=-1):
         mlab.draw(brain._f)
         mlab.savefig(filename, figure=brain._f)
 
-    def save_image(self, filename):
+    def save_image(self, filename, mode='rgb', antialiased=False):
         """Save view from all panels to disk
 
         Only mayavi image types are supported:
@@ -2020,15 +2020,23 @@ def save_image(self, filename):
         ----------
         filename: string
             path to new image file
+        mode: string
+            Either 'rgb' (default) to render solid background, or 'rgba' to
+            include alpha channel for transparent background
+        antialiased: bool
+            Antialias the image (see mlab.screenshot() for details; default
+            False)
 
+        Notes
+        -----
         Due to limitations in TraitsUI, if multiple views or hemi='split'
         is used, there is no guarantee painting of the windows will
         complete before control is returned to the command line. Thus
         we strongly recommend using only one figure window (which uses
         a Mayavi figure to plot instead of TraitsUI) if you intend to
         script plotting commands.
         """
-        misc.imsave(filename, self.screenshot())
+        misc.imsave(filename, self.screenshot(mode, antialiased))
 
     def screenshot(self, mode='rgb', antialiased=False):
         """Generate a screenshot of current view
@@ -2040,11 +2048,8 @@ def screenshot(self, mode='rgb', antialiased=False):
         mode: string
             Either 'rgb' or 'rgba' for values to return
         antialiased: bool
-            Antialias the image (see mlab.screenshot() for details)
-        row : int
-            row index of the brain to use
-        col : int
-            column index of the brain to use
+            Antialias the image (see mlab.screenshot() for details; default
+            False)
 
         Returns
         -------