examples/deepzoom: Add command-line option to control JPEG quality

Author: bgilbert

examples/deepzoom/deepzoom_server.py

@@ -30,6 +30,7 @@
 DEEPZOOM_FORMAT = 'jpeg'
 DEEPZOOM_TILE_SIZE = 256
 DEEPZOOM_OVERLAP = 1
+DEEPZOOM_TILE_QUALITY = 75
 SLIDE_NAME = 'slide'
 
 app = Flask(__name__)
@@ -96,7 +97,7 @@ def tile(slug, level, col, row, format):
         # Invalid level or coordinates
         abort(404)
     buf = StringIO()
-    tile.save(buf, format, quality=75)
+    tile.save(buf, format, quality=app.config['DEEPZOOM_TILE_QUALITY'])
     resp = make_response(buf.getvalue())
     resp.mimetype = 'image/%s' % format
     return resp
@@ -132,6 +133,9 @@ def slugify(text, delim=u'-'):
     parser.add_option('-p', '--port', metavar='PORT', dest='port',
                 type='int', default=5000,
                 help='port to listen on [5000]')
+    parser.add_option('-q', '--quality', metavar='QUALITY',
+                dest='DEEPZOOM_TILE_QUALITY', type='int',
+                help='JPEG compression quality [75]')
     parser.add_option('-s', '--size', metavar='PIXELS',
                 dest='DEEPZOOM_TILE_SIZE', type='int',
                 help='tile size [256]')

examples/deepzoom/deepzoom_tile.py

@@ -36,13 +36,14 @@
 class TileWorker(Process):
     """A child process that generates and writes tiles."""
 
-    def __init__(self, queue, slidepath, tile_size, overlap):
+    def __init__(self, queue, slidepath, tile_size, overlap, quality):
         Process.__init__(self, name='TileWorker')
         self.daemon = True
         self._queue = queue
         self._slidepath = slidepath
         self._tile_size = tile_size
         self._overlap = overlap
+        self._quality = quality
         self._slide = None
 
     def run(self):
@@ -59,7 +60,7 @@ def run(self):
                 dz = self._get_dz(associated)
                 last_associated = associated
             tile = dz.get_tile(level, address)
-            tile.save(outfile, quality=90)
+            tile.save(outfile, quality=self._quality)
             self._queue.task_done()
 
     def _get_dz(self, associated=None):
@@ -121,7 +122,7 @@ class DeepZoomStaticTiler(object):
     """Handles generation of tiles and metadata for all images in a slide."""
 
     def __init__(self, slidepath, basename, format, tile_size, overlap,
-                workers, with_viewer):
+                quality, workers, with_viewer):
         if with_viewer:
             # Check extra dependency before doing a bunch of work
             import jinja2
@@ -135,7 +136,7 @@ def __init__(self, slidepath, basename, format, tile_size, overlap,
         self._with_viewer = with_viewer
         self._dzi_data = {}
         for _i in range(workers):
-            TileWorker(self._queue, slidepath, tile_size, overlap).start()
+            TileWorker(self._queue, slidepath, tile_size, overlap, quality).start()
 
     def run(self):
         self._run_image()
@@ -234,6 +235,9 @@ def _shutdown(self):
                 help='number of worker processes to start [4]')
     parser.add_option('-o', '--output', metavar='NAME', dest='basename',
                 help='base name of output file')
+    parser.add_option('-q', '--quality', metavar='QUALITY', dest='quality',
+                type='int', default=90,
+                help='JPEG compression quality [90]')
     parser.add_option('-r', '--viewer', dest='with_viewer',
                 action='store_true',
                 help='generate directory tree with HTML viewer')
@@ -250,5 +254,5 @@ def _shutdown(self):
         opts.basename = os.path.splitext(os.path.basename(slidepath))[0]
 
     DeepZoomStaticTiler(slidepath, opts.basename, opts.format,
-                opts.tile_size, opts.overlap, opts.workers,
+                opts.tile_size, opts.overlap, opts.quality, opts.workers,
                 opts.with_viewer).run()