pip

build/lib/pcv/helpers.py

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+#!/usr/bin/env python3
+
+import cv2
+
+def downsize(img, ratio):
+    ''' downsize 'img' by 'ratio'. '''
+    return cv2.resize(img,
+                      tuple(dim // ratio for dim in reversed(img.shape[:2])),
+                      interpolation = cv2.INTER_AREA)
+
+def channel_options(img, rank=False):
+    ''' Create a composite image of img in all of opencv's colour channels
+
+    |img| -> | blue       | green      | red         |
+             | hue        | saturation | value       |
+             | hue2       | luminosity | saturation2 |
+             | lightness  | green-red  | blue-yellow |
+             | lightness2 | u          | v           |
+
+    'rank' is a boolean? specifying whether to also return a ranking of each
+        channel by variability/sharpness/contrast/other? !NOT YET IMPLEMENTED!
+        TODO
+        -> make a string maybe, with several options available, or select
+            multiple options in a list and get back an array or dataframe or
+            something
+        -> important to make nicely stackable to run on video and determine
+           statistics on the best option for a given use case
+
+    '''
+    B,G,R = cv2.split(img)
+    H,S,V = cv2.split(cv2.cvtColor(img, cv2.COLOR_BGR2HSV))
+    H2,L2,S2 = cv2.split(cv2.cvtColor(img, cv2.COLOR_BGR2HLS))
+    L,a,b = cv2.split(cv2.cvtColor(img, cv2.COLOR_BGR2LAB))
+    L3,u,v = cv2.split(cv2.cvtColor(img, cv2.COLOR_BGR2LUV))
+    channels = (((B, 'blue'), (G, 'green'), (R, 'red')),
+                ((H, 'hue'), (S, 'saturation'), (V, 'value')),
+                ((H2, 'hue2'), (L2, 'luminosity'), (S2, 'saturation2')),
+                ((L, 'lightness'), (a, 'green-red'), (b, 'blue-yellow')),
+                ((L3,'lightness2'), (u, 'u'), (v, 'v')))
+    out = []
+    for row in channels:
+        img_row = []
+        for img, name in row:
+            cv2.putText(img, name, (10, 30), cv2.FONT_HERSHEY_SIMPLEX,
+                        0.6, 255, 1)
+            img_row.append(img)
+        out.append(cv2.hconcat(img_row))
+    return cv2.vconcat(out)

build/lib/pcv/interact.py

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+#!/usr/bin/env python3
+
+import cv2
+
+
+waitKey = lambda ms : cv2.waitKey(ms) & 0xFF
+
+
+class DoNothing:
+    ''' A context manager that does nothing. '''
+    def __init__(self): pass
+    def __enter__(self): return self
+    def __exit__(self, *args): pass
+
+
+class MouseCallback:
+    ''' A context manager for temporary mouse callbacks. '''
+    def __init__(self, window, handler, param=None,
+                 restore=lambda *args: None, restore_param=None):
+        ''' Initialise with the window, handler, and restoration command.
+
+        'window' is the name of the window to set the callback for.
+        'handler' is the function for handling the callback, which should take
+            x, y, flags ('&'ed EVENT_FLAG bits), and an optional param passed
+            in from the callback handler.
+        'param' is any Python object that should get passed to the handler
+            on each call - useful for tracking state.
+        'restore' is the function to restore as the handler on context exit.
+        'restore_param' is the handler param to restore on context exit.
+
+        '''
+        self.window        = window
+        self.handler       = handler
+        self.param         = param
+        self.restore       = restore
+        self.restore_param = restore_param
+
+    def __enter__(self):
+        cv2.setMouseCallback(self.window, self.handler, self.param)
+        return self
+
+    def __exit__(self, *args):
+        cv2.setMouseCallback(self.window, self.restore, self.restore_param)