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      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 from autotest_lib.client.common_lib import utils
     10 
     11 
     12 class ImageGenerator(object):
     13     """A class to generate the calibration images with different sizes.
     14 
     15     It generates the SVG images which are easy to be produced by changing its
     16     XML text content.
     17 
     18     """
     19 
     20     TEMPLATE_WIDTH = 1680
     21     TEMPLATE_HEIGHT = 1052
     22     TEMPLATE_FILENAME = 'template-%dx%d.svg' % (TEMPLATE_WIDTH, TEMPLATE_HEIGHT)
     23 
     24 
     25     def __init__(self):
     26         """Construct an ImageGenerator.
     27         """
     28         module_dir = os.path.dirname(sys.modules[__name__].__file__)
     29         template_path = os.path.join(module_dir, 'calibration_images',
     30                                      self.TEMPLATE_FILENAME)
     31         self._image_template = open(template_path).read()
     32 
     33 
     34     def generate_image(self, width, height, filename):
     35         """Generate the image with the given width and height.
     36 
     37         @param width: The width of the image.
     38         @param height: The height of the image.
     39         @param filename: The filename to output, svg file or other format.
     40         """
     41         if filename.endswith('.svg'):
     42             filename_svg = filename
     43         else:
     44             filename_svg = filename + '.svg'
     45 
     46         with open(filename_svg, 'w+') as f:
     47             logging.debug('Generate the image with size %dx%d to %s',
     48                           width, height, filename_svg)
     49             f.write(self._image_template.format(
     50                     scale_width=float(width)/self.TEMPLATE_WIDTH,
     51                     scale_height=float(height)/self.TEMPLATE_HEIGHT))
     52 
     53         # Convert to different format if needed.
     54         if filename_svg != filename:
     55             utils.run('convert %s %s' % (filename_svg, filename))
     56 
     57 
     58     @staticmethod
     59     def get_extrema(image):
     60         """Returns a 2-tuple containing minimum and maximum values of the image.
     61 
     62         @param image: the calibration image projected by DUT.
     63         @return a tuple of (minimum, maximum)
     64         """
     65         w, h = image.size
     66         min_value = 255
     67         max_value = 0
     68         # scan the middle vertical line
     69         x = w / 2
     70         for i in range(0, h/2):
     71             v = image.getpixel((x, i))[0]
     72             if v < min_value:
     73                 min_value = v
     74             if v > max_value:
     75                 max_value = v
     76         return (min_value, max_value)
     77