Add JPEG as an image format for inline backend if PIL/pillow is available.

IPython/core/pylabtools.py

@@ -94,8 +94,8 b' def figsize(sizex, sizey):'
     matplotlib.rcParams['figure.figsize'] = [sizex, sizey]
 
 
-def print_figure(fig, fmt='png'):
-    """Convert a figure to svg or png for inline display."""
+def print_figure(fig, fmt='png', quality=90):
+    """Convert a figure to svg, jpg (if PIL is installed) or png for inline display."""
     from matplotlib import rcParams
     # When there's an empty figure, we shouldn't return anything, otherwise we
     # get big blank areas in the qt console.
@@ -110,7 +110,7 b" def print_figure(fig, fmt='png'):"
         dpi = dpi * 2
         fmt = 'png'
     fig.canvas.print_figure(bytes_io, format=fmt, bbox_inches='tight',
-                            facecolor=fc, edgecolor=ec, dpi=dpi)
+                            facecolor=fc, edgecolor=ec, dpi=dpi, quality=quality)
     data = bytes_io.getvalue()
     return data
     
@@ -163,7 +163,7 b' def mpl_runner(safe_execfile):'
     return mpl_execfile
 
 
-def select_figure_format(shell, fmt):
+def select_figure_format(shell, fmt, quality):
     """Select figure format for inline backend, can be 'png', 'retina', or 'svg'.
 
     Using this method ensures only one figure format is active at a time.
@@ -173,10 +173,14 b' def select_figure_format(shell, fmt):'
 
     svg_formatter = shell.display_formatter.formatters['image/svg+xml']
     png_formatter = shell.display_formatter.formatters['image/png']
+    jpg_formatter = shell.display_formatter.formatters['image/jpeg']
 
     if fmt == 'png':
         svg_formatter.pop(Figure, None)
         png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png'))
+    elif fmt in ('jpg', 'jpeg'):
+        svg_formatter.type_printers.pop(Figure, None)
+        jpg_formatter.for_type(Figure, lambda fig: print_figure(fig, 'jpg', quality))
     elif fmt in ('png2x', 'retina'):
         svg_formatter.pop(Figure, None)
         png_formatter.for_type(Figure, retina_figure)
@@ -338,5 +342,5 b' def configure_inline_support(shell, backend):'
             del shell._saved_rcParams
 
     # Setup the default figure format
-    select_figure_format(shell, cfg.figure_format)
+    select_figure_format(shell, cfg.figure_format, cfg.quality)
 

IPython/kernel/zmq/pylab/config.py

@@ -14,13 +14,19 b' This module does not import anything from matplotlib.'
 #-----------------------------------------------------------------------------
 
 from IPython.config.configurable import SingletonConfigurable
-from IPython.utils.traitlets import Dict, Instance, CaselessStrEnum, Bool
+from IPython.utils.traitlets import Dict, Instance, CaselessStrEnum, Bool, Int
 from IPython.utils.warn import warn
 
 #-----------------------------------------------------------------------------
 # Configurable for inline backend options
 #-----------------------------------------------------------------------------
 
+try:
+    from PIL import Image
+    has_pil = True
+except:
+    has_pil = False
+
 # inherit from InlineBackendConfig for deprecation purposes
 class InlineBackendConfig(SingletonConfigurable):
     pass
@@ -53,7 +59,20 b' class InlineBackend(InlineBackendConfig):'
         inline backend."""
     )
 
-    figure_format = CaselessStrEnum(['svg', 'png', 'retina'], default_value='png', config=True,
+    fmts = ['svg', 'png', 'retina']
+
+    if has_pil:
+        # If we have PIL using jpeg as inline image format can save some bytes.
+        fmts.append('jpg')
+
+    # Matplotlib's JPEG printer supports a quality option that can be tweaked.
+    # We expose it only if PIL is available so the user isn't confused. But it
+    # isn't guarded by "has_pil" test because core/pylabtools.py expects this
+    # field OR we need to propagate the has_pil test to that module too.
+    quality = Int(default_value=90, config=has_pil,
+                  help="Quality of compression [0-100], currently for lossy JPEG only.")
+
+    figure_format = CaselessStrEnum(fmts, default_value='png', config=True,
         help="The image format for figures with the inline backend.")
 
     def _figure_format_changed(self, name, old, new):