| # Copyright 2014 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| import logging |
| import os |
| import sys |
| |
| |
| class ImageGenerator(object): |
| """A class to generate the calibration images with different sizes. |
| |
| It generates the SVG images which are easy to be produced by changing its |
| XML text content. |
| |
| """ |
| |
| TEMPLATE_WIDTH = 1680 |
| TEMPLATE_HEIGHT = 1052 |
| TEMPLATE_FILENAME = 'template-%dx%d.svg' % (TEMPLATE_WIDTH, TEMPLATE_HEIGHT) |
| |
| |
| def __init__(self): |
| """Construct an ImageGenerator. |
| """ |
| module_dir = os.path.dirname(sys.modules[__name__].__file__) |
| template_path = os.path.join(module_dir, 'calibration_images', |
| self.TEMPLATE_FILENAME) |
| self._image_template = open(template_path).read() |
| |
| |
| def generate_image(self, width, height, filename): |
| """Generate the image with the given width and height. |
| |
| @param width: The width of the image. |
| @param height: The height of the image. |
| @param filename: The filename to output. |
| """ |
| with open(filename, 'w+') as f: |
| logging.debug('Generate the image with size %dx%d to %s', |
| width, height, filename) |
| f.write(self._image_template.format( |
| scale_width=float(width)/self.TEMPLATE_WIDTH, |
| scale_height=float(height)/self.TEMPLATE_HEIGHT)) |
| |
| @staticmethod |
| def get_extrema(image): |
| """Returns a 2-tuple containing minimum and maximum values of the image. |
| |
| @param image: the calibration image projected by DUT. |
| @return a tuple of (minimum, maximum) |
| """ |
| w, h = image.size |
| min_value = 255 |
| max_value = 0 |
| # scan the middle vertical line |
| x = w / 2 |
| for i in range(0, h/2): |
| v = image.getpixel((x, i))[0] |
| if v < min_value: |
| min_value = v |
| if v > max_value: |
| max_value = v |
| return (min_value, max_value) |