Add OpenGL support to the benchmark program (#659)

enable/gcbench/bench.py

@@ -21,6 +21,7 @@
         "kiva.agg": "enable.null.image",
         "cairo": "enable.null.cairo",
         "celiagg": "enable.null.celiagg",
+        "opengl": "enable.gcbench.opengl",
         "qpainter": "enable.null.qpainter",
         "quartz": "enable.null.quartz",
     },

enable/gcbench/opengl.py

@@ -0,0 +1,39 @@
+# (C) Copyright 2005-2021 Enthought, Inc., Austin, TX
+# All rights reserved.
+#
+# This software is provided without warranty under the terms of the BSD
+# license included in LICENSE.txt and may be redistributed only under
+# the conditions described in the aforementioned license. The license
+# is also available online at http://www.enthought.com/licenses/BSD.txt
+#
+# Thanks for using Enthought open source!
+import pyglet
+from pyglet.image.codecs.png import PNGImageEncoder
+
+import kiva.gl as gl_backend
+
+# Pass it along
+CompiledPath = gl_backend.CompiledPath
+
+
+class GraphicsContext(gl_backend.GraphicsContext):
+    """ This is a wrapper of the GL GraphicsContext which works in headless
+    mode.
+    """
+    def __init__(self, size, *args, **kw):
+        width, height = size
+        self.__window = pyglet.window.Window(width=width, height=height)
+        super().__init__((width, height), base_pixel_scale=1.0)
+        self.gl_init()
+
+    def clear(self, *args):
+        self.__window.clear()
+
+    def save(self, filename, *args, **kw):
+        buffer = pyglet.image.get_buffer_manager()
+        with open(filename, mode="wb") as fp:
+            buffer.get_color_buffer().save(
+                filename,
+                file=fp,
+                encoder=PNGImageEncoder(),
+            )