feat: add bbox tocenter function

Author: nunenuh

bbox.py

@@ -0,0 +1,18 @@
+def tocenter(bbox, pad={'r':100, 'l':50, 't':50, 'b':100}, ratio=1):
+    x,y,w,h=bbox
+    ratio_real = h/w
+    if w>h:
+        hn = int(w * ratio)
+        wn = w
+    else:
+        hn = h
+        wn = int(h * ratio)
+    
+    yn=(y + (h//2)) - (hn//2)
+    xn=(x + (w//2)) - (wn//2)
+    xn = xn - pad['l']
+    yn = yn - pad['t']
+    hn = hn + pad['b']
+    wn = wn + pad['r']
+    
+    return (xn, yn, wn, hn)