Working #301: added rectangle detection in pixel segmentation

The algorithm for processing user-defined geometries only works on rectangles.  Polygons are ignored.

(This commit was done after a previous revert.  Had to recommit because I deleted some code.)

rodan/jobs/gamera/custom/pixel_segment/celery_task.py

@@ -2,26 +2,29 @@
 import sys
 from gamera.core import init_gamera, load_image
 from gamera.plugins.pil_io import from_pil
-#import Image
-#import ImageDraw
 from rodan.jobs.gamera.custom.gamera_custom_base import GameraCustomTask
 
-
 class PixelSegmentTask(GameraCustomTask):
     max_retries = None
     name = 'gamera.custom.lyric_extraction.pixel_segment'
 
     settings = [{'visibility': False, 'default': 0, 'has_default': True, 'rng': (-1048576, 1048576), 'name': 'image_width', 'type': 'int'},
                 {'visibility': False, 'default': None, 'has_default': True, 'name': 'geometries', 'type': 'json'}]
 
+    # Preconfiguration setup.
     def preconfigure_settings(self, page_url, settings):
+
         init_gamera()
         task_image = load_image(page_url)
         miyao_settings = settings.copy()
         del miyao_settings['image_width']
         return {'image_width': task_image.ncols}
 
+    # Given an image and coloured geometries from the associated interactive
+    # job, converts non-white pixels in each geometry in the image to the
+    # specified colour.
     def process_image(self, task_image, settings):
+
         # Get the returned data.
         try:
             geometries = json.loads(settings['geometries'])
@@ -33,7 +36,8 @@ def process_image(self, task_image, settings):
 
         # For each of the geometries provided, we have to apply the pixel colour to non-white pixels.
         for geometry in geometries:
-            imageOriginal = self._apply_geometry(imageOriginal, geometry)
+            if self._is_rectangle(geometry['points']):
+                imageOriginal = self._apply_geometry(imageOriginal, geometry)
 
         # Convert red to white and black to green.
         colour_swap = {(255, 0, 0): (255, 255, 255), (0, 255, 0): (0, 0, 0)}
@@ -44,6 +48,22 @@ def process_image(self, task_image, settings):
         finalImage = from_pil(imageOriginal)
         return finalImage
 
+    # Returns true iff provided geometry points form a rectangle.
+    # It assumes at least 3 points.
+    def _is_rectangle(self, geometryPoints):
+
+        if len(geometryPoints) != 4:
+            return False
+
+        return ((geometryPoints[0]['y'] == geometryPoints[1]['y'] and
+                 geometryPoints[1]['x'] == geometryPoints[2]['x'] and
+                 geometryPoints[2]['y'] == geometryPoints[3]['y'] and
+                 geometryPoints[3]['x'] == geometryPoints[0]['x']) or
+                (geometryPoints[0]['x'] == geometryPoints[1]['x'] and
+                 geometryPoints[1]['y'] == geometryPoints[2]['y'] and
+                 geometryPoints[2]['x'] == geometryPoints[3]['x'] and
+                 geometryPoints[3]['y'] == geometryPoints[0]['y']))
+
     # Given image and geometry (with colour and working vs original dimensions), apply it to the image.
     def _apply_geometry(self, image, geometry):