Source code for als.crunching

"""
A set of shared utilities for number crunching
"""
import logging

import numpy as np
from als.code_utilities import log

from als.model.data import HistogramContainer

_LOGGER = logging.getLogger(__name__)


@log
def compute_histograms_for_display(image, bin_count):
    """
    Compute histograms
    """
    container = HistogramContainer()

    if image.is_color():
        for channel in range(3):
            container.add_histogram(_compute_single_channel_histogram_for_display(image.data[:, :, channel], bin_count))
    else:
        container.add_histogram(_compute_single_channel_histogram_for_display(image.data, bin_count))

    container.global_maximum = max([histo.max() for histo in container.get_histograms()])

    return container


@log
def _compute_single_channel_histogram_for_display(channel_data, bin_count):

    histogram = np.histogram(channel_data, bin_count, range=(0, 2**16 - 1))[0]

    # we set extremity bins' values to 0 to prevent wrong display on clipped histograms
    histogram[0] = 0

    for current_bin in reversed(range(0, bin_count)):
        if histogram[current_bin] > 0:
            histogram[current_bin] = 0
            break

    return histogram