bgneal@1: """ Function for generating web 2.0 style image reflection effects.
bgneal@1: 
bgneal@1: Copyright (c) 2007, Justin C. Driscoll
bgneal@1: All rights reserved.
bgneal@1: 
bgneal@1: Redistribution and use in source and binary forms, with or without modification,
bgneal@1: are permitted provided that the following conditions are met:
bgneal@1: 
bgneal@1:     1. Redistributions of source code must retain the above copyright notice,
bgneal@1:        this list of conditions and the following disclaimer.
bgneal@1: 
bgneal@1:     2. Redistributions in binary form must reproduce the above copyright
bgneal@1:        notice, this list of conditions and the following disclaimer in the
bgneal@1:        documentation and/or other materials provided with the distribution.
bgneal@1: 
bgneal@1:     3. Neither the name of reflection.py nor the names of its contributors may be used
bgneal@1:        to endorse or promote products derived from this software without
bgneal@1:        specific prior written permission.
bgneal@1: 
bgneal@1: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
bgneal@1: ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
bgneal@1: WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
bgneal@1: DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
bgneal@1: ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
bgneal@1: (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
bgneal@1: LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
bgneal@1: ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
bgneal@1: (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
bgneal@1: SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
bgneal@1: 
bgneal@1: """
bgneal@1: 
bgneal@1: try:
bgneal@1:     import Image
bgneal@1:     import ImageColor                    
bgneal@1: except ImportError:
bgneal@1:     try:
bgneal@1:         from PIL import Image
bgneal@1:         from PIL import ImageColor
bgneal@1:     except ImportError:
bgneal@1:         raise ImportError("The Python Imaging Library was not found.")
bgneal@1:     
bgneal@1:     
bgneal@1: def add_reflection(im, bgcolor="#00000", amount=0.4, opacity=0.6):
bgneal@1:     """ Returns the supplied PIL Image (im) with a reflection effect
bgneal@1:     
bgneal@1:     bgcolor  The background color of the reflection gradient
bgneal@1:     amount   The height of the reflection as a percentage of the orignal image
bgneal@1:     opacity  The initial opacity of the reflection gradient
bgneal@1:     
bgneal@1:     Originally written for the Photologue image management system for Django
bgneal@1:     and Based on the original concept by Bernd Schlapsi
bgneal@1:     
bgneal@1:     """
bgneal@1:     # convert bgcolor string to rgb value
bgneal@1:     background_color = ImageColor.getrgb(bgcolor)
bgneal@1:     
bgneal@1:     # copy orignial image and flip the orientation
bgneal@1:     reflection = im.copy().transpose(Image.FLIP_TOP_BOTTOM)
bgneal@1:     
bgneal@1:     # create a new image filled with the bgcolor the same size
bgneal@1:     background = Image.new("RGB", im.size, background_color)
bgneal@1:     
bgneal@1:     # calculate our alpha mask
bgneal@1:     start = int(255 - (255 * opacity)) # The start of our gradient
bgneal@1:     steps = int(255 * amount) # the number of intermedite values
bgneal@1:     increment = (255 - start) / float(steps)
bgneal@1:     mask = Image.new('L', (1, 255))
bgneal@1:     for y in range(255):
bgneal@1:         if y < steps:
bgneal@1:             val = int(y * increment + start)
bgneal@1:         else:
bgneal@1:             val = 255
bgneal@1:         mask.putpixel((0, y), val)
bgneal@1:     alpha_mask = mask.resize(im.size)    
bgneal@1:     
bgneal@1:     # merge the reflection onto our background color using the alpha mask
bgneal@1:     reflection = Image.composite(background, reflection, alpha_mask)
bgneal@1:     
bgneal@1:     # crop the reflection
bgneal@1:     reflection_height = int(im.size[1] * amount)
bgneal@1:     reflection = reflection.crop((0, 0, im.size[0], reflection_height))
bgneal@1:     
bgneal@1:     # create new image sized to hold both the original image and the reflection
bgneal@1:     composite = Image.new("RGB", (im.size[0], im.size[1]+reflection_height), background_color)
bgneal@1:     
bgneal@1:     # paste the orignal image and the reflection into the composite image
bgneal@1:     composite.paste(im, (0, 0))
bgneal@1:     composite.paste(reflection, (0, im.size[1]))
bgneal@1:     
bgneal@1:     # return the image complete with reflection effect
bgneal@1:     return composite
bgneal@1: