""" Function for generating web 2.0 style image reflection effects.

Copyright (c) 2007, Justin C. Driscoll

All rights reserved.

Redistribution and use in source and binary forms, with or without modification,

are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,

       this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright

       notice, this list of conditions and the following disclaimer in the

       documentation and/or other materials provided with the distribution.

    3. Neither the name of reflection.py nor the names of its contributors may be used

       to endorse or promote products derived from this software without

       specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR

ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON

ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

"""

try:

    import Image

    import ImageColor

except ImportError:

    try:

        from PIL import Image

        from PIL import ImageColor

    except ImportError:

        raise ImportError("The Python Imaging Library was not found.")

def add_reflection(im, bgcolor="#00000", amount=0.4, opacity=0.6):

    """ Returns the supplied PIL Image (im) with a reflection effect

    bgcolor  The background color of the reflection gradient

    amount   The height of the reflection as a percentage of the orignal image

    opacity  The initial opacity of the reflection gradient

    Originally written for the Photologue image management system for Django

    and Based on the original concept by Bernd Schlapsi

    """

    # convert bgcolor string to rgb value

    background_color = ImageColor.getrgb(bgcolor)

    # copy orignial image and flip the orientation

    reflection = im.copy().transpose(Image.FLIP_TOP_BOTTOM)

    # create a new image filled with the bgcolor the same size

    background = Image.new("RGB", im.size, background_color)

    # calculate our alpha mask

    start = int(255 - (255 * opacity)) # The start of our gradient

    steps = int(255 * amount) # the number of intermedite values

    increment = (255 - start) / float(steps)

    mask = Image.new('L', (1, 255))

    for y in range(255):

        if y < steps:

            val = int(y * increment + start)

        else:

            val = 255

        mask.putpixel((0, y), val)

    alpha_mask = mask.resize(im.size)

    # merge the reflection onto our background color using the alpha mask

    reflection = Image.composite(background, reflection, alpha_mask)

    # crop the reflection

    reflection_height = int(im.size[1] * amount)

    reflection = reflection.crop((0, 0, im.size[0], reflection_height))

    # create new image sized to hold both the original image and the reflection

    composite = Image.new("RGB", (im.size[0], im.size[1]+reflection_height), background_color)

    # paste the orignal image and the reflection into the composite image

    composite.paste(im, (0, 0))

    composite.paste(reflection, (0, im.size[1]))

    # return the image complete with reflection effect

    return composite