# This file is part of the pyMOR project (http://www.pymor.org).
# Copyright Holders: Rene Milk, Stephan Rave, Felix Schindler
# License: BSD 2-Clause License (http://opensource.org/licenses/BSD-2-Clause)

from __future__ import absolute_import, division, print_function

import numpy as np

from scipy.ndimage import imread

from pymor.functions.basic import FunctionBase


class BitmapFunction(FunctionBase):
    """Define a 2D function via a grayscale image.

    Parameters
    ----------
    filename
        Path of the image representing the function.
    bounding_box
        Lower left and upper right coordinates of the domain of the function.
    range
        A pixel of value p is mapped to ``(p / 255.) * range[1] + range[0]``.
    """

    dim_domain = 2
    shape_range = tuple()

    def __init__(self, filename, bounding_box=[[0., 0.], [1., 1.]], range=[0., 1.]):
        self.bitmap = imread(filename).T[:, ::-1]
        assert self.bitmap.ndim == 2, 'A grayscale image is needed.'
        self.bounding_box = bounding_box
        self.lower_left = np.array(bounding_box[0])
        self.size = np.array(bounding_box[1] - self.lower_left)
        self.range = range

    def evaluate(self, x, mu=None):
        indices = np.maximum(np.floor((x - self.lower_left) * np.array(self.bitmap.shape) / self.size).astype(int), 0)
        F = self.bitmap[np.minimum(indices[..., 0], self.bitmap.shape[0] - 1),
                        np.minimum(indices[..., 1], self.bitmap.shape[1] - 1)] * (self.range[1] / 255.) + self.range[0]
        return F

# This file is part of the pyMOR project (http://www.pymor.org).
# Copyright Holders: Rene Milk, Stephan Rave, Felix Schindler
# License: BSD 2-Clause License (http://opensource.org/licenses/BSD-2-Clause)

from __future__ import absolute_import, division, print_function

import numpy as np

from pymor.functions.basic import FunctionBase


class BitmapFunction(FunctionBase):
    """Define a 2D function via a grayscale image.

    Parameters
    ----------
    filename
        Path of the image representing the function.
    bounding_box
        Lower left and upper right coordinates of the domain of the function.
    range
        A pixel of value p is mapped to ``(p / 255.) * range[1] + range[0]``.
    """

    dim_domain = 2
    shape_range = tuple()

    def __init__(self, filename, bounding_box=[[0., 0.], [1., 1.]], range=[0., 1.]):
        try:
            from PIL import Image
        except ImportError:
            raise ImportError("PIL is needed for loading images. Try 'pip install pillow'")
        self.bitmap = np.array(Image.open(filename)).T[:, ::-1]
        assert self.bitmap.ndim == 2, 'A grayscale image is needed.'
        self.bounding_box = bounding_box
        self.lower_left = np.array(bounding_box[0])
        self.size = np.array(bounding_box[1] - self.lower_left)
        self.range = range

    def evaluate(self, x, mu=None):
        indices = np.maximum(np.floor((x - self.lower_left) * np.array(self.bitmap.shape) / self.size).astype(int), 0)
        F = self.bitmap[np.minimum(indices[..., 0], self.bitmap.shape[0] - 1),
                        np.minimum(indices[..., 1], self.bitmap.shape[1] - 1)] * (self.range[1] / 255.) + self.range[0]
        return F

fix BitmapFunction for older SciPy versions