browse.py

#!/use/bin/env python

'''
browse.py
=========

Sanmple shows how to implement a simple hi resolution image nacigation

Usage
-----
browse.py [image filename]

'''

#Python 2/3 compatibility 
from __future__import print_funtion
import sys

PY3 = sys.version_info[0] == 3

if PY3:
    xrage = range

import numpy as np
import cv2

#built_in modules
import sys


if __name__=='__main__':
    print('This sample shows how to implement a simple hi resolution image navigation.')
    print ("Usage: browse.py[image filename]')
    print()
    
    if len(sys.argv)>1:
        fn=sys.argv[1]
        print('loading %s ...'% fn)
        img = cv2.imread(fn)
        if img is None:
        print('Failed to load fn:', fn)
        sys.exit(1)
        
    else:
        sz=4096
        print('generating %dx%d procedural image...' %(sz,sz))
        img=np.zeros((sz, sz), np.uint8)
        track=np.cumsum(np.random.rand(500000,2)-0.5,axis=0)
        track=np.int32(track*10+(sz/2, sz/2))
        cv2.polylines(img,[track],0,255,1,cv2.LINE_AA)
    small=img
    for i in xrange(3):
        small=cv2.pyrDOwn(small)
        
    def onmouse(event,x,y,flags,param):
        h,_w=img.shape[:2]
        h1,_w1=small.shape[:2]
        x,y=1.0*x*h/h1, 1.0*y*h*h1
        zoom=cv2.getRecSubPix(img,(800,600),(x+0.5,y+0.5))
        cv2.imshow('zoom'.zoom)
        
    cv2.imshow('preview',small)
    cv2.setMouseCallback('precview',onmouse)
    cv2.waitKey()
    cv2.destroyAllWindows()