def check_web_color_contrast(self, settings):
"""
Verify that the web primary and secondary color both contrast
well on white, as these colors will serve as button backgrounds with
white test, as well as text color on white backgrounds.
"""
primary = flask.request.form.get(
Configuration.WEB_PRIMARY_COLOR,
Configuration.DEFAULT_WEB_PRIMARY_COLOR)
secondary = flask.request.form.get(
Configuration.WEB_SECONDARY_COLOR,
Configuration.DEFAULT_WEB_SECONDARY_COLOR)
def hex_to_rgb(hex):
hex = hex.lstrip("#")
return tuple(int(hex[i:i + 2], 16) / 255.0 for i in (0, 2, 4))
primary_passes = wcag_contrast_ratio.passes_AA(
wcag_contrast_ratio.rgb(hex_to_rgb(primary),
hex_to_rgb("#ffffff")))
secondary_passes = wcag_contrast_ratio.passes_AA(
wcag_contrast_ratio.rgb(hex_to_rgb(secondary),
hex_to_rgb("#ffffff")))
if not (primary_passes and secondary_passes):
primary_check_url = ("https://contrast-ratio.com/#%23" +
secondary[1:] + "-on-%23" + "#ffffff"[1:])
secondary_check_url = ("https://contrast-ratio.com/#%23" +
secondary[1:] + "-on-%23" + "#ffffff"[1:])
return INVALID_CONFIGURATION_OPTION.detailed(
_(
"The web primary and secondary colors don't have enough contrast to pass the WCAG 2.0 AA guidelines and will be difficult for some patrons to read. Check contrast for primary <a href='%(primary_check_url)s' target='_blank'>here</a> and secondary <a href='%(primary_check_url)s' target='_blank'>here</a>.",
primary_check_url=primary_check_url,
secondary_check_url=secondary_check_url,
))
def text_color(color):
rgb = tuple(int(color[i:i + 2], 16) / 255.0 for i in (0, 2, 4))
white = (1.0, 1.0, 1.0)
black = (0.0, 0.0, 0.0)
if contrast.rgb(rgb, white) > contrast.rgb(rgb, black):
return "FFFFFF"
else:
return "000000"
def contrast_color(hex_color):
rgb_color = colors.hex2color(hex_color)
black = (0.0, 0.0, 0.0)
black_contrast = contrast.rgb(rgb_color, black)
white = (1.0, 1.0, 1.0)
white_contrast = contrast.rgb(rgb_color, white)
if white_contrast > black_contrast:
return "#ffffff"
else:
return "#000000"
def check_web_color_contrast(self, settings):
"""Verify that the web background color and web foreground
color go together.
"""
background = flask.request.form.get(Configuration.WEB_BACKGROUND_COLOR, Configuration.DEFAULT_WEB_BACKGROUND_COLOR)
foreground = flask.request.form.get(Configuration.WEB_FOREGROUND_COLOR, Configuration.DEFAULT_WEB_FOREGROUND_COLOR)
def hex_to_rgb(hex):
hex = hex.lstrip("#")
return tuple(int(hex[i:i+2], 16)/255.0 for i in (0, 2 ,4))
if not wcag_contrast_ratio.passes_AA(wcag_contrast_ratio.rgb(hex_to_rgb(background), hex_to_rgb(foreground))):
contrast_check_url = "https://contrast-ratio.com/#%23" + foreground[1:] + "-on-%23" + background[1:]
return INVALID_CONFIGURATION_OPTION.detailed(
_("The web background and foreground colors don't have enough contrast to pass the WCAG 2.0 AA guidelines and will be difficult for some patrons to read. Check contrast <a href='%(contrast_check_url)s' target='_blank'>here</a>.",
contrast_check_url=contrast_check_url))
def get_style_contrasts(style_cls):
return [
(
round(
wcag_contrast_ratio.rgb(
hex2rgb(style["bgcolor"] or style_cls.background_color),
hex2rgb(style["color"] or "#000000")
# we default to black because browsers also do
),
1,
),
ttype,
) for ttype, style in style_cls.list_styles()
if ttype != pygments.token.Whitespace
]
def colorChecker(backgroundColor, textColor):
if backgroundColor is None:
backgroundColor = "Gray"
if textColor is None:
textColor = "Black"
# convert color name to rgb for contrast check
textRGB = ([i / 255 for i in webcolors.name_to_rgb(textColor)])
# convert color name to rgb for contrast check
backgroundRGB = ([i / 255 for i in webcolors.name_to_rgb(backgroundColor)])
# check contrast ratio
if contrast.passes_AA(contrast.rgb(textRGB, backgroundRGB)):
return webcolors.name_to_hex(backgroundColor), webcolors.name_to_hex(
textColor)
# if failed, set color to default
return webcolors.name_to_hex("Gray"), webcolors.name_to_hex("Black")
def black_or_white(color):
"""give the contrast between white/black and color and give wich of black
or white give the best contrast (return black or white)"""
# input are number between 0 and 1
black = (1, 1, 1)
white = (0, 0, 0)
color[:] = color[:] / 255
# calculate the contrast between black and color
b_c = contrast.rgb(black, color)
# calculate the contrast between white and color
w_c = contrast.rgb(black, color)
output_color = 'empty'
if (b_c > w_c):
output_color = 'black'
else:
output_color = 'white'
return (output_color)
def choose_tint_color(dominant_colors, background_color):
# The minimum contrast ratio for text and background to meet WCAG AA
# is 4.5:1, so discard any dominant colours with a lower contrast.
sufficient_contrast_colors = [
col for col in dominant_colors
if contrast.rgb(col, background_color) >= 4.5
]
# If none of the dominant colours meet WCAG AA with the background,
# try again with black and white -- every colour in the RGB space
# has a contrast ratio of 4.5:1 with at least one of these, so we'll
# get a tint colour, even if it's not a good one.
#
# Note: you could modify the dominant colours until one of them
# has sufficient contrast, but that's omitted here because it adds
# a lot of complexity for a relatively unusual case.
if not sufficient_contrast_colors:
return choose_tint_color(dominant_colors=dominant_colors + [(0, 0, 0),
(1, 1, 1)],
background_color=background_color)
# Of the colours with sufficient contrast, pick the one with the
# closest brightness (in the HSV colour space) to the background
# colour. This means we don't get very dark or very light colours,
# but more bright, vibrant colours.
hsv_background = colorsys.rgb_to_hsv(*background_color)
hsv_candidates = {
tuple(rgb_col): colorsys.rgb_to_hsv(*rgb_col)
for rgb_col in sufficient_contrast_colors
}
candidates_by_brightness_diff = {
rgb_col: abs(hsv_col[2] - hsv_background[2])
for rgb_col, hsv_col in hsv_candidates.items()
}
rgb_choice, _ = min(candidates_by_brightness_diff.items(),
key=lambda t: t[1])
assert rgb_choice in dominant_colors
return rgb_choice
def check_web_color_contrast(self, settings):
"""Verify that the web background color and web foreground
color go together.
"""
background = flask.request.form.get(
Configuration.WEB_BACKGROUND_COLOR,
Configuration.DEFAULT_WEB_BACKGROUND_COLOR)
foreground = flask.request.form.get(
Configuration.WEB_FOREGROUND_COLOR,
Configuration.DEFAULT_WEB_FOREGROUND_COLOR)
def hex_to_rgb(hex):
hex = hex.lstrip("#")
return tuple(int(hex[i:i + 2], 16) / 255.0 for i in (0, 2, 4))
if not wcag_contrast_ratio.passes_AA(
wcag_contrast_ratio.rgb(hex_to_rgb(background),
hex_to_rgb(foreground))):
contrast_check_url = "https://contrast-ratio.com/#%23" + foreground[
1:] + "-on-%23" + background[1:]
return INVALID_CONFIGURATION_OPTION.detailed(
_("The web background and foreground colors don't have enough contrast to pass the WCAG 2.0 AA guidelines and will be difficult for some patrons to read. Check contrast <a href='%(contrast_check_url)s' target='_blank'>here</a>.",
contrast_check_url=contrast_check_url))
def plot_map(stations, connections, lines, area, output_path="./output/plot/"):
"""
Plot all the lines on a Map and save as png-file
parameters:
stations - all stations in database;
connections - all connections in database;
lines - the lines that are plotted;
area - geographical area of lines;
output_path - folder where plot is saved;
"""
# Create Figure and Axe
fig = plt.figure(dpi=600)
fig, ax = plt.subplots()
plt.axis("off")
# Format Options of Holland and others
if area == "Holland":
land_color = tuple(i / 255. for i in ImageColor.getrgb("#0AE"))
marker_size = 10
line_size = 1
else: # if area == "Nationaal":
land_color = tuple(i / 255. for i in ImageColor.getrgb("#E06"))
marker_size = 5
line_size = .75
# predefine used colors
used_colors = []
# Plot Background using geopandas
gpd_map(area).plot(ax=ax, color=land_color)
# For-loop to get each individual connection between stations
for connection in connections:
# Create tuples of x and y using coordinates of begin- and end station
connect_long = [station.position[0] for station in connection.section]
connect_lat = [station.position[1] for station in connection.section]
# Plot connection
ax.plot(connect_long,
connect_lat,
linewidth=line_size,
color="lightgrey",
alpha=0.5,
zorder=1)
# Create lists of x and y values from the coordinates of all stations
station_long = [station.position[0] for station in stations.values()]
station_lat = [station.position[1] for station in stations.values()]
# Calculate the ratio between the longitude and latitude
ratio = aspect_ratio(station_lat)
# Create a dictionary of connections that need ofset
ofset = ofset_dict(lines)
# For-loop to get each single line
for line_number in range(len(lines)):
# generate random color
color = random_color()
# generate new color the contrast is high enough no double colors
while (rgb(color, land_color) >= 10 and color not in used_colors):
color = random_color()
# add color to used color
used_colors.append(color)
# For-loop to get each connection in a line
for connection in list(set(lines[line_number].connections)):
# Get the adjusted longitude and latitude
longitude, latitude = line_coords(connection, ofset, ratio,
line_number)
# Plot connection
ax.plot(longitude,
latitude,
c=color,
linewidth=line_size,
zorder=2)
# Plot all stations
ax.scatter(station_long,
station_lat,
s=marker_size,
marker="o",
color="black",
zorder=3)
# Set aspect using ratio value
ax.set_aspect(ratio)
# Save plot to png file
plt.savefig(f"{output_path}Map-{area}.png",
dpi=300,
format="png",
transparent=True)
print(f"Map-{area} is created.")
def get_contrast_ratio(color_1, color_2):
return contrast.rgb(color_1, color_2)
def score_contrast(a, b, large, AAA):
contrast = cr.rgb(a, b) # Between 1 and 21
return contrast \
+ int((AAA and cr.passes_AAA(contrast, large=large))) * 100 \
+ int(not AAA and cr.passes_AA(contrast, large=large)) * 100
def get_contrast(color_1, color_2):
return contrast.rgb(get_rgb_from_color(color_1),
get_rgb_from_color(color_2))
def run(tag_data):
"""
Modifies the background and foreground color of text content and background
to increase the contrast.
Parameters:
html <list> Dictionaries with HTML snippets as strings and hexadecimal
color of the background and foreground
Return:
<list> List of beautiful soup tags with proper CSS contrast elements and their path
"""
back = hex_to_rgb(tag_data["colors"]["background"])
fore = hex_to_rgb(tag_data["colors"]["foreground"]) # Text color
# True if the background is closer to white than black
backLight = is_light(back)
# Set initial conditions for the foreground text color
cond = {
"contrast":
not contrast.passes_AA(
contrast.rgb([v / RGB_LIMIT
for v in back], [v / RGB_LIMIT for v in fore])),
"notLightest":
max(fore) < RGB_LIMIT or backLight,
"notDarkest":
all(fore) or not backLight,
}
# Loop to adjust the foreground colors
while all(cond.values()):
fore = [
color + (-min(COLOR_STEP, color) if backLight else min(
COLOR_STEP, RGB_LIMIT - color)) for color in fore
]
cond["contrast"] = not contrast.passes_AA(
contrast.rgb([v / RGB_LIMIT
for v in back], [v / RGB_LIMIT for v in fore]))
cond["notLightest"] = max(fore) < RGB_LIMIT or backLight
cond["notDarkest"] = all(fore) or not backLight
# Now we adjust the conditions to the background colors
cond["notLightest"] = max(back) < RGB_LIMIT or not backLight
cond["notDarkest"] = all(back) or backLight
# Loop to adjust the background colors
while all(cond.values()):
back = [
color + (min(COLOR_STEP, RGB_LIMIT -
color) if backLight else -min(COLOR_STEP, color))
for color in back
]
cond["contrast"] = not contrast.passes_AA(
contrast.rgb([v / RGB_LIMIT
for v in back], [v / RGB_LIMIT for v in fore]))
cond["notLightest"] = max(back) < RGB_LIMIT or not backLight
cond["notDarkest"] = all(back) or backLight
snippet = tag_data["snippet"]
if not snippet.has_attr("style"):
snippet["style"] = ""
backChanged = rgb_to_hex(back) != tag_data["colors"]["background"]
# Remove "background-color" styles if its color was changed
if backChanged and "background-color" in snippet["style"]:
start = snippet["style"].find("background-color")
end = snippet["style"].find(";", start) + 1
snippet["style"] = snippet["style"].replace(
snippet["style"][start:end], "")
# Remove "background" styles if its color was changed
if backChanged and "background" in snippet["style"]:
start = snippet["style"].find("background")
end = snippet["style"].find(";", start) + 1
snippet["style"] = snippet["style"].replace(
snippet["style"][start:end], "")
# Remove "color" styles
if "color" in snippet["style"]:
start = snippet["style"].find("color")
end = snippet["style"].find(";", start) + 1
snippet["style"] = snippet["style"].replace(
snippet["style"][start:end], "")
# Add the new calculated styles
snippet["style"] += f"color: #{rgb_to_hex(fore)}; "
snippet[
"style"] += f"background: #{rgb_to_hex(back)}; " if backChanged else ""
tag_data["snippet"] = snippet
return tag_data
def test_hypothesis_contrast(rgb1, rgb2):
c1 = contrast.rgb(rgb1, rgb2)
c2 = contrast.rgb(rgb2, rgb1)
assert 1.0 <= c1 <= 21.0
assert c1 == c2
def test_contrast(rgb1, rgb2, expected):
c1 = contrast.rgb(rgb1, rgb2)
c2 = contrast.rgb(rgb2, rgb1)
assert c1 == expected
assert c2 == expected