add expand

1 files changed, 16 insertions, 0 deletions

diff --git a/megapixels/app/models/bbox.py b/megapixels/app/models/bbox.py
index 40874691..f1216698 100644
--- a/megapixels/app/models/bbox.py
+++ b/megapixels/app/models/bbox.py
@@ -130,6 +130,22 @@ class BBox:
   # -----------------------------------------------------------------
   # Modify
 
+  def expand(self, per):
+    """Expands BBox by percentage
+    :param per: (float) percentage to expand 0.0 - 1.0
+    :param dim: (int, int) image width, height
+    :returns (BBox) expanded
+    """
+    # expand
+    dw, dh = [(self._width * per), (self._height * per)]
+    r = list(np.array(self._rect) + np.array([-dw, -dh, dw, dh]))
+    # threshold expanded rectangle
+    r[0] = max(r[0], 0.0)
+    r[1] = max(r[1], 0.0)
+    r[2] = min(r[2], 1.0)
+    r[3] = min(r[3], 1.0)
+    return BBox(*r)
+
   def expand_dim(self, amt, bounds):
     """Expands BBox within dim
     :param box: (tuple) left, top, right, bottom