1#!/usr/bin/env python
2
3'''
4browse.py
5=========
6
7Sample shows how to implement a simple hi resolution image navigation
8
9Usage
10-----
11browse.py [image filename]
12
13'''
14
15import numpy as np
16import cv2
17
18# built-in modules
19import sys
20
21if __name__ == '__main__':
22    print 'This sample shows how to implement a simple hi resolution image navigation.'
23    print 'USAGE: browse.py [image filename]'
24    print
25
26    if len(sys.argv) > 1:
27        fn = sys.argv[1]
28        print 'loading %s ...' % fn
29        img = cv2.imread(fn)
30        if img is None:
31            print 'Failed to load fn:', fn
32            sys.exit(1)
33
34    else:
35        sz = 4096
36        print 'generating %dx%d procedural image ...' % (sz, sz)
37        img = np.zeros((sz, sz), np.uint8)
38        track = np.cumsum(np.random.rand(500000, 2)-0.5, axis=0)
39        track = np.int32(track*10 + (sz/2, sz/2))
40        cv2.polylines(img, [track], 0, 255, 1, cv2.LINE_AA)
41
42
43    small = img
44    for i in xrange(3):
45        small = cv2.pyrDown(small)
46
47    def onmouse(event, x, y, flags, param):
48        h, w = img.shape[:2]
49        h1, w1 = small.shape[:2]
50        x, y = 1.0*x*h/h1, 1.0*y*h/h1
51        zoom = cv2.getRectSubPix(img, (800, 600), (x+0.5, y+0.5))
52        cv2.imshow('zoom', zoom)
53
54    cv2.imshow('preview', small)
55    cv2.setMouseCallback('preview', onmouse)
56    cv2.waitKey()
57    cv2.destroyAllWindows()
58