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
5import logging
6import os
7import sys
8
9from autotest_lib.client.common_lib import utils
10
11
12class 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