def height2image(height):
"""
Converts a dictionary of heights (or brightnesses) on a grid to
an image.
Args:
height (dict): A dictionary in which keys are coordinates
for points on a grid, and the values are positive
numbers of any type.
Returns:
image (Image): Monochrome image for which the given height
dictionary determines the brightness of each pixel. The
maximum value in the height dictionary is always white.
"""
Lx, Ly = _get_size(height)
h_max = max(height.values())
image = newimage('L', (Lx, Ly))
for x in range(Lx):
for y in range(Ly):
if (x, y) in height:
h = float(height[x, y]) / h_max
else:
h = 0
image.putpixel((x, y), int(255 * h))
return image
def row_swap_images(image0, image1, fraction, log=False):
"""
A variant of `swap_images` in which the swap process is done on each line
of the images individually, rather than with the images as a whole. This
makes it much faster.
Args:
image0, image1 (Image): RGB encoded images.
fraction (float): Fraction of swap gates to apply.
log (bool): If given, a logarithmic decoding is used.
Returns:
new_image0, new_image1 (Image): RGB encoded images.
"""
images = [image0, image1]
Lx, Ly = images[0].size
# create separate images for each row
rows = [[], []]
for j in range(2):
for y in range(Ly):
rows[j].append(newimage('RGB', (Lx, 1)))
for x in range(Lx):
rows[j][y].putpixel((x, 0), images[j].getpixel((x, y)))
# do the swap on the row images
for y in range(Ly):
rows[0][y], rows[1][y] = swap_images(rows[0][y],
rows[1][y],
fraction,
log=log)
# reconstruct the full images
new_images = [newimage('RGB', (Lx, Ly)) for _ in range(2)]
for j in range(2):
for y in range(Ly):
for x in range(Lx):
new_images[j].putpixel((x, y), rows[j][y].getpixel((x, 0)))
return new_images[0], new_images[1]
def _heights2image(heights):
"""
Constructs an image from a set of three height dictionaries, one for each
colour channel.
"""
Lx, Ly = _get_size(heights[0])
h_max = [max(height.values()) for height in heights]
image = newimage('RGB', (Lx, Ly))
for x in range(Lx):
for y in range(Ly):
rgb = []
for j, height in enumerate(heights):
if (x, y) in height:
h = float(height[x, y]) / h_max[j]
else:
h = 0
rgb.append(int(255 * h))
image.putpixel((x, y), tuple(rgb))
return image
