[Telemetry] Migrate bitmap.py from bitmaptools.cc to numpy

tools/telemetry/telemetry/core/bitmap.py

Index: tools/telemetry/telemetry/core/bitmap.py
diff --git a/tools/telemetry/telemetry/core/bitmap.py b/tools/telemetry/telemetry/core/bitmap.py
deleted file mode 100644
index ead38b1c97c7b0dbc8996b0c2fd051a0f1ab0057..0000000000000000000000000000000000000000
--- a/tools/telemetry/telemetry/core/bitmap.py
+++ /dev/null
@@ -1,353 +0,0 @@
-# Copyright 2013 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-"""
-Bitmap is a basic wrapper for image pixels. It includes some basic processing
-tools: crop, find bounding box of a color and compute histogram of color values.
-"""
-
-import array
-import base64
-import cStringIO
-import collections
-import struct
-import subprocess
-
-from telemetry.core import util
-from telemetry.core import platform
-from telemetry.util import support_binaries
-
-util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'png')
-import png  # pylint: disable=F0401
-
-
-def HistogramDistance(hist1, hist2):
-  """Earth mover's distance.
-
-  http://en.wikipedia.org/wiki/Earth_mover's_distance
-  First, normalize the two histograms. Then, treat the two histograms as
-  piles of dirt, and calculate the cost of turning one pile into the other.
-
-  To do this, calculate the difference in one bucket between the two
-  histograms. Then carry it over in the calculation for the next bucket.
-  In this way, the difference is weighted by how far it has to move."""
-  if len(hist1) != len(hist2):
-    raise ValueError('Trying to compare histograms '
-      'of different sizes, %s != %s' % (len(hist1), len(hist2)))
-
-  n1 = sum(hist1)
-  n2 = sum(hist2)
-  if n1 == 0:
-    raise ValueError('First histogram has 0 pixels in it.')
-  if n2 == 0:
-    raise ValueError('Second histogram has 0 pixels in it.')
-
-  total = 0
-  remainder = 0
-  for value1, value2 in zip(hist1, hist2):
-    remainder += value1 * n2 - value2 * n1
-    total += abs(remainder)
-  assert remainder == 0, (
-      '%s pixel(s) left over after computing histogram distance.'
-      % abs(remainder))
-  return abs(float(total) / n1 / n2)
-
-
-class ColorHistogram(
-    collections.namedtuple('ColorHistogram', ['r', 'g', 'b', 'default_color'])):
-  # pylint: disable=W0232
-  # pylint: disable=E1002
-
-  def __new__(cls, r, g, b, default_color=None):
-    return super(ColorHistogram, cls).__new__(cls, r, g, b, default_color)
-
-  def Distance(self, other):
-    total = 0
-    for i in xrange(3):
-      hist1 = self[i]
-      hist2 = other[i]
-
-      if sum(self[i]) == 0:
-        if not self.default_color:
-          raise ValueError('Histogram has no data and no default color.')
-        hist1 = [0] * 256
-        hist1[self.default_color[i]] = 1
-      if sum(other[i]) == 0:
-        if not other.default_color:
-          raise ValueError('Histogram has no data and no default color.')
-        hist2 = [0] * 256
-        hist2[other.default_color[i]] = 1
-
-      total += HistogramDistance(hist1, hist2)
-    return total
-
-
-class RgbaColor(collections.namedtuple('RgbaColor', ['r', 'g', 'b', 'a'])):
-  """Encapsulates an RGBA color retreived from a Bitmap"""
-  # pylint: disable=W0232
-  # pylint: disable=E1002
-
-  def __new__(cls, r, g, b, a=255):
-    return super(RgbaColor, cls).__new__(cls, r, g, b, a)
-
-  def __int__(self):
-    return (self.r << 16) | (self.g << 8) | self.b
-
-  def IsEqual(self, expected_color, tolerance=0):
-    """Verifies that the color is within a given tolerance of
-    the expected color"""
-    r_diff = abs(self.r - expected_color.r)
-    g_diff = abs(self.g - expected_color.g)
-    b_diff = abs(self.b - expected_color.b)
-    a_diff = abs(self.a - expected_color.a)
-    return (r_diff <= tolerance and g_diff <= tolerance
-        and b_diff <= tolerance and a_diff <= tolerance)
-
-  def AssertIsRGB(self, r, g, b, tolerance=0):
-    assert self.IsEqual(RgbaColor(r, g, b), tolerance)
-
-  def AssertIsRGBA(self, r, g, b, a, tolerance=0):
-    assert self.IsEqual(RgbaColor(r, g, b, a), tolerance)
-
-
-WEB_PAGE_TEST_ORANGE = RgbaColor(222, 100, 13)
-WHITE = RgbaColor(255, 255, 255)
-
-
-class _BitmapTools(object):
-  """Wraps a child process of bitmaptools and allows for one command."""
-  CROP_PIXELS = 0
-  HISTOGRAM = 1
-  BOUNDING_BOX = 2
-
-  def __init__(self, dimensions, pixels):
-    binary = support_binaries.FindPath(
-        'bitmaptools',
-        platform.GetHostPlatform().GetArchName(),
-        platform.GetHostPlatform().GetOSName())
-    assert binary, 'You must build bitmaptools first!'
-
-    self._popen = subprocess.Popen([binary],
-                                   stdin=subprocess.PIPE,
-                                   stdout=subprocess.PIPE,
-                                   stderr=subprocess.PIPE)
-
-    # dimensions are: bpp, width, height, boxleft, boxtop, boxwidth, boxheight
-    packed_dims = struct.pack('iiiiiii', *dimensions)
-    self._popen.stdin.write(packed_dims)
-    # If we got a list of ints, we need to convert it into a byte buffer.
-    if type(pixels) is not bytearray:
-      pixels = bytearray(pixels)
-    self._popen.stdin.write(pixels)
-
-  def _RunCommand(self, *command):
-    assert not self._popen.stdin.closed, (
-      'Exactly one command allowed per instance of tools.')
-    packed_command = struct.pack('i' * len(command), *command)
-    self._popen.stdin.write(packed_command)
-    self._popen.stdin.close()
-    length_packed = self._popen.stdout.read(struct.calcsize('i'))
-    if not length_packed:
-      raise Exception(self._popen.stderr.read())
-    length = struct.unpack('i', length_packed)[0]
-    return self._popen.stdout.read(length)
-
-  def CropPixels(self):
-    return self._RunCommand(_BitmapTools.CROP_PIXELS)
-
-  def Histogram(self, ignore_color, tolerance):
-    ignore_color_int = -1 if ignore_color is None else int(ignore_color)
-    response = self._RunCommand(_BitmapTools.HISTOGRAM,
-                                ignore_color_int, tolerance)
-    out = array.array('i')
-    out.fromstring(response)
-    assert len(out) == 768, (
-        'The ColorHistogram has the wrong number of buckets: %s' % len(out))
-    return ColorHistogram(out[:256], out[256:512], out[512:], ignore_color)
-
-  def BoundingBox(self, color, tolerance):
-    response = self._RunCommand(_BitmapTools.BOUNDING_BOX, int(color),
-                                tolerance)
-    unpacked = struct.unpack('iiiii', response)
-    box, count = unpacked[:4], unpacked[-1]
-    if box[2] < 0 or box[3] < 0:
-      box = None
-    return box, count
-
-
-class Bitmap(object):
-  """Utilities for parsing and inspecting a bitmap."""
-
-  def __init__(self, bpp, width, height, pixels, metadata=None):
-    assert bpp in [3, 4], 'Invalid bytes per pixel'
-    assert width > 0, 'Invalid width'
-    assert height > 0, 'Invalid height'
-    assert pixels, 'Must specify pixels'
-    assert bpp * width * height == len(pixels), 'Dimensions and pixels mismatch'
-
-    self._bpp = bpp
-    self._width = width
-    self._height = height
-    self._pixels = pixels
-    self._metadata = metadata or {}
-    self._crop_box = None
-
-  @property
-  def bpp(self):
-    """Bytes per pixel."""
-    return self._bpp
-
-  @property
-  def width(self):
-    """Width of the bitmap."""
-    return self._crop_box[2] if self._crop_box else self._width
-
-  @property
-  def height(self):
-    """Height of the bitmap."""
-    return self._crop_box[3] if self._crop_box else self._height
-
-  def _PrepareTools(self):
-    """Prepares an instance of _BitmapTools which allows exactly one command.
-    """
-    crop_box = self._crop_box or (0, 0, self._width, self._height)
-    return _BitmapTools((self._bpp, self._width, self._height) + crop_box,
-                        self._pixels)
-
-  @property
-  def pixels(self):
-    """Flat pixel array of the bitmap."""
-    if self._crop_box:
-      self._pixels = self._PrepareTools().CropPixels()
-      # pylint: disable=unpacking-non-sequence
-      _, _, self._width, self._height = self._crop_box
-      self._crop_box = None
-    if type(self._pixels) is not bytearray:
-      self._pixels = bytearray(self._pixels)
-    return self._pixels
-
-  @property
-  def metadata(self):
-    self._metadata['size'] = (self.width, self.height)
-    self._metadata['alpha'] = self.bpp == 4
-    self._metadata['bitdepth'] = 8
-    return self._metadata
-
-  def GetPixelColor(self, x, y):
-    """Returns a RgbaColor for the pixel at (x, y)."""
-    pixels = self.pixels
-    base = self._bpp * (y * self._width + x)
-    if self._bpp == 4:
-      return RgbaColor(pixels[base + 0], pixels[base + 1],
-                       pixels[base + 2], pixels[base + 3])
-    return RgbaColor(pixels[base + 0], pixels[base + 1],
-                     pixels[base + 2])
-
-  def WritePngFile(self, path):
-    with open(path, "wb") as f:
-      png.Writer(**self.metadata).write_array(f, self.pixels)
-
-  @staticmethod
-  def FromPng(png_data):
-    width, height, pixels, meta = png.Reader(bytes=png_data).read_flat()
-    return Bitmap(4 if meta['alpha'] else 3, width, height, pixels, meta)
-
-  @staticmethod
-  def FromPngFile(path):
-    with open(path, "rb") as f:
-      return Bitmap.FromPng(f.read())
-
-  @staticmethod
-  def FromBase64Png(base64_png):
-    return Bitmap.FromPng(base64.b64decode(base64_png))
-
-  def IsEqual(self, other, tolerance=0):
-    """Determines whether two Bitmaps are identical within a given tolerance."""
-
-    # Dimensions must be equal
-    if self.width != other.width or self.height != other.height:
-      return False
-
-    # Loop over each pixel and test for equality
-    if tolerance or self.bpp != other.bpp:
-      for y in range(self.height):
-        for x in range(self.width):
-          c0 = self.GetPixelColor(x, y)
-          c1 = other.GetPixelColor(x, y)
-          if not c0.IsEqual(c1, tolerance):
-            return False
-    else:
-      return self.pixels == other.pixels
-
-    return True
-
-  def Diff(self, other):
-    """Returns a new Bitmap that represents the difference between this image
-    and another Bitmap."""
-
-    # Output dimensions will be the maximum of the two input dimensions
-    out_width = max(self.width, other.width)
-    out_height = max(self.height, other.height)
-
-    diff = [[0 for x in xrange(out_width * 3)] for x in xrange(out_height)]
-
-    # Loop over each pixel and write out the difference
-    for y in range(out_height):
-      for x in range(out_width):
-        if x < self.width and y < self.height:
-          c0 = self.GetPixelColor(x, y)
-        else:
-          c0 = RgbaColor(0, 0, 0, 0)
-
-        if x < other.width and y < other.height:
-          c1 = other.GetPixelColor(x, y)
-        else:
-          c1 = RgbaColor(0, 0, 0, 0)
-
-        offset = x * 3
-        diff[y][offset] = abs(c0.r - c1.r)
-        diff[y][offset+1] = abs(c0.g - c1.g)
-        diff[y][offset+2] = abs(c0.b - c1.b)
-
-    # This particular method can only save to a file, so the result will be
-    # written into an in-memory buffer and read back into a Bitmap
-    diff_img = png.from_array(diff, mode='RGB')
-    output = cStringIO.StringIO()
-    try:
-      diff_img.save(output)
-      diff = Bitmap.FromPng(output.getvalue())
-    finally:
-      output.close()
-
-    return diff
-
-  def GetBoundingBox(self, color, tolerance=0):
-    """Finds the minimum box surrounding all occurences of |color|.
-    Returns: (top, left, width, height), match_count
-    Ignores the alpha channel."""
-    return self._PrepareTools().BoundingBox(color, tolerance)
-
-  def Crop(self, left, top, width, height):
-    """Crops the current bitmap down to the specified box."""
-    cur_box = self._crop_box or (0, 0, self._width, self._height)
-    cur_left, cur_top, cur_width, cur_height = cur_box
-
-    if (left < 0 or top < 0 or
-        (left + width) > cur_width or
-        (top + height) > cur_height):
-      raise ValueError('Invalid dimensions')
-
-    self._crop_box = cur_left + left, cur_top + top, width, height
-    return self
-
-  def ColorHistogram(self, ignore_color=None, tolerance=0):
-    """Computes a histogram of the pixel colors in this Bitmap.
-    Args:
-      ignore_color: An RgbaColor to exclude from the bucket counts.
-      tolerance: A tolerance for the ignore_color.
-
-    Returns:
-      A ColorHistogram namedtuple with 256 integers in each field: r, g, and b.
-    """
-    return self._PrepareTools().Histogram(ignore_color, tolerance)