# Copyright (c) 2021 VisualDL Authors. All Rights Reserve.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# =======================================================================


def figure_to_image(figures, close=True):
    """Render matplotlib figure to numpy format.

    Note that this requires the ``matplotlib`` package.

    Args:
        figure (matplotlib.pyplot.figure) : figure
        close (bool): Flag to automatically close the figure

    Returns:
        numpy.array: image in [HWC] order
    """
    import numpy as np
    try:
        import matplotlib.pyplot as plt
        import matplotlib.backends.backend_agg as plt_backend_agg
    except ModuleNotFoundError:
        print('please install matplotlib')

    def render_to_rgb(figure):
        canvas = plt_backend_agg.FigureCanvasAgg(figure)
        canvas.draw()
        data = np.frombuffer(canvas.buffer_rgba(), dtype=np.uint8)
        w, h = figure.canvas.get_width_height()
        image_hwc = data.reshape([h, w, 4])[:, :, 0:3]
        if close:
            plt.close(figure)
        return image_hwc

    image = render_to_rgb(figures)
    return image