# Copyright (c) 2017, System Engineering Software Society
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from __future__ import (print_function, division, unicode_literals,
absolute_import)
from sympathy.api import node
from sympathy.api.nodeconfig import Port, Ports, Tag, Tags
import numpy as np
from sylib.imageprocessing.image import Image
from sylib.imageprocessing.algorithm_selector import ImageFiltering_abstract
[docs]class OverlayImages(ImageFiltering_abstract, node.Node):
name = 'Overlay Images'
author = 'Mathias Broxvall'
copyright = '(C) 2017 System Engineering Software Society'
version = '0.1'
icon = 'image_overlay.svg'
description = (
'Combines two images by layering the first (top port) image on top of '
'the other (bottom port) image\n, with choice for combining operator. '
'Images must have the same number of channels')
nodeid = 'syip.overlay'
tags = Tags(Tag.ImageProcessing.Layers)
default_parameters = {
'use alpha channel': 'Use last channel of source images as alpha channel',
'alpha': 'Alpha value used when no alpha channel is given'
}
algorithms = {
'additive': dict({
'description': 'Adds the two images together where they overlap.',
'unity': 0.0,
'expr': lambda result, im: result + im,
'multichromatic': True
}, **default_parameters),
'multiplicative': dict({
'description': 'Multiplies images where they overlap.',
'unity': 1.0,
'expr': lambda result, im: result * im,
'multichromatic': True
}, **default_parameters),
'divide': dict({
'description': 'Divides bottom image by all other images.',
'unity': 1.0,
'expr': lambda result, im: result / im,
'multichromatic': True
}, **default_parameters),
'subtract': dict({
'description': 'Subtracts top image from bottom.',
'unity': 0.0,
'expr': lambda result, im: result - im,
'multichromatic': True
}, **default_parameters),
'max': dict({
'description': 'Takes the maximum value of the images.',
'unity': 0.0,
'expr': lambda result, im: np.maximum(result, im),
'multichromatic': True
}, **default_parameters),
'min': dict({
'description': 'Takes the minimum value of the images.',
'unity': 0.0,
'expr': lambda result, im: np.minimum(result, im),
'multichromatic': True
}, **default_parameters),
'layer': dict({
'description': (
'Layers on image on top of the other, alpha channel (if any) '
'determines transparency. Otherwise alpha value below'),
'unity': 0.0,
'expr': lambda result, im: im,
'multichromatic': True
}, **default_parameters),
}
options_list = [
'use alpha channel', 'alpha'
]
options_types = {
'use alpha channel': bool, 'alpha': float
}
options_default = {
'use alpha channel': False, 'alpha': 1.0
}
parameters = node.parameters()
parameters.set_string(
'algorithm', value=next(iter(algorithms)), description='', label='Algorithm')
ImageFiltering_abstract.generate_parameters(
parameters, options_types, options_default)
inputs = Ports([
Port.Custom('image', 'Input images', name='images', n=(2,))
])
outputs = Ports([
Image('result after filtering', name='result'),
])
__doc__ = ImageFiltering_abstract.generate_docstring(
description, algorithms, options_list, inputs, outputs)
def execute(self, node_context):
images = [
obj.get_image() for obj in node_context.input.group('images')]
params = node_context.parameters
alg_name = params['algorithm'].value
use_alpha = params['use alpha channel'].value
# Reshape so all images guaranteed to have 3 dimensions
images = [
(im.reshape(im.shape + (1,)) if len(im.shape) < 3 else im)
for im in images]
# Compute max size
max_y = max([im.shape[0] for im in images])
max_x = max([im.shape[1] for im in images])
max_c = max([im.shape[2] for im in images])
if alg_name == 'multiplicative':
unity = 1.0
elif alg_name == 'divide':
unity = 1.0
else:
unity = 0.0
result = np.full((max_y, max_x, max_c), unity)
bot = images[-1]
result[:bot.shape[0], :bot.shape[1], :bot.shape[2]] = bot
rest = images[:-1]
alpha = params['alpha'].value
for im in rest[::-1]:
for c in range(im.shape[2]):
expr = OverlayImages.algorithms[alg_name]['expr']
y, x, _ = im.shape
if use_alpha:
result[:y, :x, c] = (
result[:y, :x, c] * (1-im[:, :, -1]) +
im[:, :, -1] * expr(result[:y, :x, c], im[:, :, c]))
else:
result[:y, :x, c] = (
result[:y, :x, c] * (1-alpha) +
alpha * expr(result[:y, :x, c], im[:, :, c]))
node_context.output['result'].set_image(result)
return