Require pixel arrays to be passed to TileManager.process_raw

Before, encoded pixel buffers were being passed.

mapping/enable/canvas.py

@@ -1,10 +1,10 @@
-from __future__ import print_function
+from __future__ import division, print_function
 
 import math
-from io import BytesIO
 
 from enable.api import Canvas, ColorTrait
-from kiva.image import Image
+from kiva.fonttools import str_to_font
+from kiva.image import GraphicsContext
 from kiva.constants import FILL
 from traits.api import Int, Range, Instance, on_trait_change
 
@@ -25,36 +25,31 @@ class MappingCanvas(Canvas):
     # FIXME This is a hack - remove when viewport is fixed
     _zoom_level = Int(0)
 
-    _blank_tile = Instance(Image)
+    _blank_tile = Instance(GraphicsContext)
 
     def __blank_tile_default(self):
-        import pkg_resources
-        from PIL import Image as PilImage
-        from PIL import ImageDraw, ImageFont
-
-        im = PilImage.new('RGB', (256, 256), (234, 224, 216))
+        gc = GraphicsContext((256, 256), pix_format='rgba32')
+        font = str_to_font('swiss 18')
+        gc.clear((0.9, 0.875, 0.85, 1.0))
 
         text = 'Image not available'
-        try:
-            font_file = pkg_resources.resource_filename(
-                'mapping.enable', 'fonts/Verdana.ttf'
-            )
-            font = ImageFont.truetype(font_file, 18)
-        except IOError:
-            font = ImageFont.load_default()
-        size = font.getsize(text)
-        pos = (256-size[0])//2, (256-size[1])//2
-
-        draw = ImageDraw.Draw(im)
-        draw.text(pos, text, fill=(200, 200, 200), font=font)
-        del draw
-
-        tile = BytesIO()
-        im.save(tile, format='png')
-        return Image(BytesIO(tile.getvalue()))
+        with gc:
+            gc.set_font(font)
+            gc.set_stroke_color((0.75, 0.75, 0.75, 1.0))
+
+            width, height, _, _ = gc.get_full_text_extent(text)
+            pos = (256 - width) // 2, (256 - height) // 2
+            gc.translate_ctm(*pos)
+            gc.show_text(text)
+        return gc
 
     def _tile_cache_changed(self, new):
-        new.process_raw = lambda d: Image(BytesIO(d))
+        fmt_map = {3: 'rgb24', 4: 'rgba32'}
+
+        def process(data):
+            return GraphicsContext(data, pix_format=fmt_map[data.shape[2]],
+                                   interpolation='nearest', bottom_up=True)
+        new.process_raw = process
 
     @on_trait_change('tile_cache:tile_ready')
     def _tile_ready(self, zoom_row_col):

mapping/enable/http_tile_manager.py

@@ -11,6 +11,7 @@
 from .tile_manager import TileManager
 from .cacheing_decorators import lru_cache
 from .async_loader import AsyncLoader, AsyncRequest, get_global_async_loader
+from .utils import img_data_to_img_array
 
 
 @provides(ITileManager)
@@ -54,8 +55,9 @@ def _async_loader_default(self):
     def _tile_received(self, tile_args, data):
         zoom, row, col = tile_args['zoom'], tile_args['row'], tile_args['col']
         try:
-            data = self.process_raw(data)
-            self.get_tile.replace(data, self, zoom, row, col)
+            img = img_data_to_img_array(data)
+            img = self.process_raw(img)
+            self.get_tile.replace(img, self, zoom, row, col)
             self.tile_ready = (zoom, row, col)
         except Exception:
             # Failed to process tile

mapping/enable/img_tile_manager.py

@@ -1,11 +1,9 @@
 from __future__ import division
 
-from io import BytesIO
 import os
 import os.path as op
 
 import numpy as np
-from PIL import Image
 
 from traits.api import String, Tuple, provides
 
@@ -33,12 +31,7 @@ def get_tile(self, zoom, row, col):
         tile_path = op.join(zoom_dir, '{}.{}.npy'.format(row, col))
         if not op.exists(tile_path):
             return None
-
-        tile = np.load(tile_path)
-        img = Image.fromarray(tile, mode='RGB')
-        data = BytesIO()
-        img.save(data, format='png')
-        return self.process_raw(data.getvalue())
+        return self.process_raw(np.load(tile_path))
 
     def get_tile_size(self):
         return 256

mapping/enable/mbtile_manager.py

@@ -1,10 +1,10 @@
-
 from traits.api import Instance, Str, provides
 
 from .i_tile_manager import ITileManager
 from .tile_manager import TileManager
 from .cacheing_decorators import lru_cache
 from .mbtiles import MbtileSet
+from .utils import img_data_to_img_array
 
 
 @provides(ITileManager)
@@ -18,7 +18,8 @@ def get_tile(self, zoom, row, col):
         if not data:
             return None
         else:
-            return self.process_raw(data)
+            img = img_data_to_img_array(data)
+            return self.process_raw(img)
 
     def get_tile_size(self):
         return 256

mapping/enable/utils.py

@@ -0,0 +1,20 @@
+from io import BytesIO
+
+import numpy as np
+from PIL import Image
+
+from kiva.compat import piltostring
+
+DEPTH_MAP = {'RGB': 3, 'RGBA': 4}
+
+
+def img_data_to_img_array(data):
+    """ Convert a buffer of encoded image data to a numpy array of pixels.
+    """
+    pil_img = Image.open(BytesIO(data))
+    if pil_img.mode not in ('RGB', 'RGBA'):
+        pil_img = pil_img.convert(mode='RGBA')
+
+    depth = DEPTH_MAP[pil_img.mode]
+    img = np.fromstring(piltostring(pil_img), np.uint8)
+    return np.resize(img, (pil_img.size[1], pil_img.size[0], depth))

setup.py

@@ -30,7 +30,6 @@
     include_package_data=True,
     package_data={
         'mapping': ['data/*'],
-        'mapping.enable': ['fonts/*'],
     },
     install_requires=__requires__,
     license='BSD',