From f79d6da2c7fa8b9402f68df6f52244a81b3a5ac2 Mon Sep 17 00:00:00 2001
From: Andrey Golovizin <ag@sologoc.com>
Date: Mon, 18 Aug 2014 19:00:53 +0200
Subject: [PATCH] Move Image.combine() and friends to module level, add support
 for more than 2 images.

---
 pixelocr/image.py | 65 +++++++++++++++++++++++++++--------------------
 pixelocr/page.py  |  7 +++--
 2 files changed, 40 insertions(+), 32 deletions(-)

diff --git a/pixelocr/image.py b/pixelocr/image.py
index 5368b1e..4e24ff2 100644
--- a/pixelocr/image.py
+++ b/pixelocr/image.py
@@ -14,6 +14,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
+import itertools
 from io import BytesIO
 
 import numpy as np
@@ -23,6 +24,42 @@ from skimage.color import rgb2gray
 from .utils import cached_property, pairwise
 
 
+def bbox(*images):
+    return (
+        min(image.left for image in images),
+        min(image.top for image in images),
+        max(image.right for image in images),
+        max(image.bottom for image in images),
+    )
+
+
+def overlap(*images):
+    for image1, image2 in itertools.combinations(images, 2):
+        xoverlap = (image1.right > image2.left and image2.right > image1.left)
+        yoverlap = (image1.bottom > image2.top and image2.bottom > image1.top)
+        if xoverlap and yoverlap:
+            return True
+    return False
+
+
+def combine(*images):
+    if overlap(*images):
+        raise NotImplementedError
+
+    left, top, right, bottom = bbox(*images)
+    width = right - left
+    height = bottom - top
+
+    data = np.zeros((height, width, images[0].data.shape[2]), images[0].data.dtype)
+    data.fill(255)
+
+    for image in images:
+        xoffset = image.left - left
+        yoffset = image.top - top
+        data[yoffset:yoffset + image.height, xoffset:xoffset + image.width] = image.data
+    return Image(data, left, top)
+
+
 def _is_nonblank(bitmap):
     """Return True if bitmap contains at least one black (=1) pixel."""
     return bitmap.any()
@@ -167,34 +204,6 @@ class Image(object):
         data = np.ma.masked_array(self.data, mask3, fill_value=255).filled()
         return Image(data, self.x, self.y)
 
-    def bbox(self, other):
-        return (
-            min(self.left, other.left),
-            min(self.top, other.top),
-            max(self.right, other.right),
-            max(self.bottom, other.bottom),
-        )
-
-    def overlaps(self, other):
-        return not (self.right < other.left or other.left < self.right)
-
-    def combine(self, other):
-        if self.overlaps(other):
-            raise NotImplementedError
-
-        left, top, right, bottom = self.bbox(other)
-        width = right - left
-        height = bottom - top
-        selftop = self.top - top
-        othertop = other.top - top
-        selfleft = self.left - left
-        otherleft = other.left - left
-        data = np.zeros((height, width, self.shape[2]), self.data.dtype)
-        data.fill(255)
-        data[selftop:selftop + self.height, selfleft:selfleft + self.width] = self.data
-        data[othertop:othertop + other.height, otherleft:otherleft + other.width] = other.data
-        return Image(data, left, top)
-
     def _iter_lines(self, min_space):
         def iter_lines():
             line_start = None
diff --git a/pixelocr/page.py b/pixelocr/page.py
index 1bd3911..90869e2 100644
--- a/pixelocr/page.py
+++ b/pixelocr/page.py
@@ -22,7 +22,7 @@ from scipy import ndimage
 from scipy.ndimage import filters
 
 from .utils import cached_property, collect_iterable, pairwise
-from .image import Image
+from .image import Image, combine
 
 
 CONNECTIVITY8 = ndimage.generate_binary_structure(2, 2)
@@ -196,9 +196,8 @@ class Glyph(PageObject):
     def add_diacritics(self, *diacritics):
         if not diacritics:
             return self
-        if len(diacritics) > 1:
-            raise NotImplementedError
-        return Glyph(self.image.combine(diacritics[0].image), self.elevation)
+        diacritic_images = (diacritic.image for diacritic in diacritics)
+        return Glyph(combine(self.image, *diacritic_images), self.elevation)
 
 
 class Space(Glyph):