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

     2 

     3 Copyright (c) 2007, Justin C. Driscoll

     4 All rights reserved.

     5 

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

     7 are permitted provided that the following conditions are met:

     8 

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

    10        this list of conditions and the following disclaimer.

    11 

    12     2. Redistributions in binary form must reproduce the above copyright

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

    14        documentation and/or other materials provided with the distribution.

    15 

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

    17        to endorse or promote products derived from this software without

    18        specific prior written permission.

    19 

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

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

    22 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

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

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

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

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

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

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

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

    30 

    31 """

    32 

    33 try:

    34     import Image

    35     import ImageColor

    36 except ImportError:

    37     try:

    38         from PIL import Image

    39         from PIL import ImageColor

    40     except ImportError:

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

    42 

    43 

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

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

    46 

    47     bgcolor  The background color of the reflection gradient

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

    49     opacity  The initial opacity of the reflection gradient

    50 

    51     Originally written for the Photologue image management system for Django

    52     and Based on the original concept by Bernd Schlapsi

    53 

    54     """

    55     # convert bgcolor string to rgb value

    56     background_color = ImageColor.getrgb(bgcolor)

    57 

    58     # copy orignial image and flip the orientation

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

    60 

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

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

    63 

    64     # calculate our alpha mask

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

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

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

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

    69     for y in range(255):

    70         if y < steps:

    71             val = int(y * increment + start)

    72         else:

    73             val = 255

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

    75     alpha_mask = mask.resize(im.size)

    76 

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

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

    79 

    80     # crop the reflection

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

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

    83 

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

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

    86 

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

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

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

    90 

    91     # return the image complete with reflection effect

    92     return composite