1 # Copyright 2014 The Chromium OS Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 import logging 6 import os 7 import sys 8 9 10 class ImageGenerator(object): 11 """A class to generate the calibration images with different sizes. 12 13 It generates the SVG images which are easy to be produced by changing its 14 XML text content. 15 16 """ 17 18 TEMPLATE_WIDTH = 1680 19 TEMPLATE_HEIGHT = 1052 20 TEMPLATE_FILENAME = 'template-%dx%d.svg' % (TEMPLATE_WIDTH, TEMPLATE_HEIGHT) 21 22 23 def __init__(self): 24 """Construct an ImageGenerator. 25 """ 26 module_dir = os.path.dirname(sys.modules[__name__].__file__) 27 template_path = os.path.join(module_dir, 'calibration_images', 28 self.TEMPLATE_FILENAME) 29 self._image_template = open(template_path).read() 30 31 32 def generate_image(self, width, height, filename): 33 """Generate the image with the given width and height. 34 35 @param width: The width of the image. 36 @param height: The height of the image. 37 @param filename: The filename to output. 38 """ 39 with open(filename, 'w+') as f: 40 logging.debug('Generate the image with size %dx%d to %s', 41 width, height, filename) 42 f.write(self._image_template.format( 43 scale_width=float(width)/self.TEMPLATE_WIDTH, 44 scale_height=float(height)/self.TEMPLATE_HEIGHT)) 45 46 @staticmethod 47 def get_extrema(image): 48 """Returns a 2-tuple containing minimum and maximum values of the image. 49 50 @param image: the calibration image projected by DUT. 51 @return a tuple of (minimum, maximum) 52 """ 53 w, h = image.size 54 min_value = 255 55 max_value = 0 56 # scan the middle vertical line 57 x = w / 2 58 for i in range(0, h/2): 59 v = image.getpixel((x, i))[0] 60 if v < min_value: 61 min_value = v 62 if v > max_value: 63 max_value = v 64 return (min_value, max_value) 65
