1 files changed, 20 insertions, 0 deletions
diff --git a/util/util.py b/util/util.py
index 7a452a6..1c03715 100644
--- a/util/util.py
+++ b/util/util.py
@@ -54,3 +54,23 @@ def mkdirs(paths):
 def mkdir(path):
     if not os.path.exists(path):
         os.makedirs(path)
+
+def crop_image(img, xy, scale_factor):
+    '''Crop the image around the tuple xy
+
+    Inputs:
+    -------
+    img: Image opened with PIL.Image
+    xy: tuple with relative (x,y) position of the center of the cropped image
+        x and y shall be between 0 and 1
+    scale_factor: the ratio between the original image's size and the cropped image's size
+    '''
+    center = (img.size[0] * xy[0], img.size[1] * xy[1])
+    new_size = (img.size[0] / scale_factor, img.size[1] / scale_factor)
+    left = max (0, (int) (center[0] - new_size[0] / 2))
+    right = min (img.size[0], (int) (center[0] + new_size[0] / 2))
+    upper = max (0, (int) (center[1] - new_size[1] / 2))
+    lower = min (img.size[1], (int) (center[1] + new_size[1] / 2))
+    cropped_img = img.crop((left, upper, right, lower))
+    return cropped_img
+