committed by
GitHub
16 changed files with 283 additions and 242 deletions
@ -0,0 +1,189 @@ |
|||
# frozen_string_literal: true |
|||
|
|||
require 'mime/types/columnar' |
|||
|
|||
module Paperclip |
|||
class ColorExtractor < Paperclip::Processor |
|||
MIN_CONTRAST = 3.0 |
|||
FREQUENCY_THRESHOLD = 0.01 |
|||
|
|||
def make |
|||
depth = 8 |
|||
|
|||
# Determine background palette by getting colors close to the image's edge only |
|||
background_palette = palette_from_histogram(convert(':source -alpha set -gravity Center -region 75%x75% -fill None -colorize 100% -alpha transparent +region -format %c -colors :quantity -depth :depth histogram:info:', source: File.expand_path(@file.path), quantity: 10, depth: depth), 10) |
|||
|
|||
# Determine foreground palette from the whole image |
|||
foreground_palette = palette_from_histogram(convert(':source -format %c -colors :quantity -depth :depth histogram:info:', source: File.expand_path(@file.path), quantity: 10, depth: depth), 10) |
|||
|
|||
background_color = background_palette.first || foreground_palette.first |
|||
foreground_colors = [] |
|||
|
|||
return @file if background_color.nil? |
|||
|
|||
max_distance = 0 |
|||
max_distance_color = nil |
|||
|
|||
foreground_palette.each do |color| |
|||
distance = ColorDiff.between(background_color, color) |
|||
|
|||
if distance > max_distance |
|||
max_distance = distance |
|||
max_distance_color = color |
|||
end |
|||
end |
|||
|
|||
foreground_colors << max_distance_color unless max_distance_color.nil? |
|||
|
|||
max_distance = 0 |
|||
max_distance_color = nil |
|||
|
|||
foreground_palette.each do |color| |
|||
distance = ColorDiff.between(background_color, color) |
|||
contrast = w3c_contrast(background_color, color) |
|||
|
|||
if distance > max_distance && contrast >= MIN_CONTRAST && !foreground_colors.include?(color) |
|||
max_distance = distance |
|||
max_distance_color = color |
|||
end |
|||
end |
|||
|
|||
foreground_colors << max_distance_color unless max_distance_color.nil? |
|||
|
|||
# If we don't have enough colors for accent and foreground, generate |
|||
# new ones by manipulating the background color |
|||
(2 - foreground_colors.size).times do |i| |
|||
foreground_colors << lighten_or_darken(background_color, 35 + (15 * i)) |
|||
end |
|||
|
|||
# We want the color with the highest contrast to background to be the foreground one, |
|||
# and the one with the highest saturation to be the accent one |
|||
foreground_color = foreground_colors.max_by { |rgb| w3c_contrast(background_color, rgb) } |
|||
accent_color = foreground_colors.max_by { |rgb| rgb_to_hsl(rgb.r, rgb.g, rgb.b)[1] } |
|||
|
|||
meta = { |
|||
colors: { |
|||
background: rgb_to_hex(background_color), |
|||
foreground: rgb_to_hex(foreground_color), |
|||
accent: rgb_to_hex(accent_color), |
|||
}, |
|||
} |
|||
|
|||
attachment.instance.file.instance_write(:meta, (attachment.instance.file.instance_read(:meta) || {}).merge(meta)) |
|||
|
|||
@file |
|||
end |
|||
|
|||
private |
|||
|
|||
def w3c_contrast(color1, color2) |
|||
luminance1 = (0.2126 * color1.r + 0.7152 * color1.g + 0.0722 * color1.b) + 0.05 |
|||
luminance2 = (0.2126 * color2.r + 0.7152 * color2.g + 0.0722 * color2.b) + 0.05 |
|||
|
|||
if luminance1 > luminance2 |
|||
luminance1 / luminance2 |
|||
else |
|||
luminance2 / luminance1 |
|||
end |
|||
end |
|||
|
|||
# rubocop:disable Style/MethodParameterName |
|||
def rgb_to_hsl(r, g, b) |
|||
r /= 255.0 |
|||
g /= 255.0 |
|||
b /= 255.0 |
|||
max = [r, g, b].max |
|||
min = [r, g, b].min |
|||
h = (max + min) / 2.0 |
|||
s = (max + min) / 2.0 |
|||
l = (max + min) / 2.0 |
|||
|
|||
if max == min |
|||
h = 0 |
|||
s = 0 # achromatic |
|||
else |
|||
d = max - min |
|||
s = l >= 0.5 ? d / (2.0 - max - min) : d / (max + min) |
|||
|
|||
case max |
|||
when r |
|||
h = (g - b) / d + (g < b ? 6.0 : 0) |
|||
when g |
|||
h = (b - r) / d + 2.0 |
|||
when b |
|||
h = (r - g) / d + 4.0 |
|||
end |
|||
|
|||
h /= 6.0 |
|||
end |
|||
|
|||
[(h * 360).round, (s * 100).round, (l * 100).round] |
|||
end |
|||
|
|||
def hue_to_rgb(p, q, t) |
|||
t += 1 if t.negative? |
|||
t -= 1 if t > 1 |
|||
|
|||
return (p + (q - p) * 6 * t) if t < 1 / 6.0 |
|||
return q if t < 1 / 2.0 |
|||
return (p + (q - p) * (2 / 3.0 - t) * 6) if t < 2 / 3.0 |
|||
|
|||
p |
|||
end |
|||
|
|||
def hsl_to_rgb(h, s, l) |
|||
h /= 360.0 |
|||
s /= 100.0 |
|||
l /= 100.0 |
|||
|
|||
r = 0.0 |
|||
g = 0.0 |
|||
b = 0.0 |
|||
|
|||
if s == 0.0 |
|||
r = l.to_f |
|||
g = l.to_f |
|||
b = l.to_f # achromatic |
|||
else |
|||
q = l < 0.5 ? l * (1 + s) : l + s - l * s |
|||
p = 2 * l - q |
|||
r = hue_to_rgb(p, q, h + 1 / 3.0) |
|||
g = hue_to_rgb(p, q, h) |
|||
b = hue_to_rgb(p, q, h - 1 / 3.0) |
|||
end |
|||
|
|||
[(r * 255).round, (g * 255).round, (b * 255).round] |
|||
end |
|||
# rubocop:enable Style/MethodParameterName |
|||
|
|||
def lighten_or_darken(color, by) |
|||
hue, saturation, light = rgb_to_hsl(color.r, color.g, color.b) |
|||
|
|||
light = begin |
|||
if light < 50 |
|||
[100, light + by].min |
|||
else |
|||
[0, light - by].max |
|||
end |
|||
end |
|||
|
|||
ColorDiff::Color::RGB.new(*hsl_to_rgb(hue, saturation, light)) |
|||
end |
|||
|
|||
def palette_from_histogram(result, quantity) |
|||
frequencies = result.scan(/([0-9]+)\:/).flatten.map(&:to_f) |
|||
hex_values = result.scan(/\#([0-9A-Fa-f]{6,8})/).flatten |
|||
total_frequencies = frequencies.reduce(&:+).to_f |
|||
|
|||
frequencies.map.with_index { |f, i| [f / total_frequencies, hex_values[i]] } |
|||
.sort_by { |r| -r[0] } |
|||
.reject { |r| r[1].size == 8 && r[1].end_with?('00') } |
|||
.map { |r| ColorDiff::Color::RGB.new(*r[1][0..5].scan(/../).map { |c| c.to_i(16) }) } |
|||
.slice(0, quantity) |
|||
end |
|||
|
|||
def rgb_to_hex(rgb) |
|||
'#%02x%02x%02x' % [rgb.r, rgb.g, rgb.b] |
|||
end |
|||
end |
|||
end |
@ -0,0 +1,14 @@ |
|||
# frozen_string_literal: true |
|||
|
|||
module Paperclip |
|||
module TranscoderExtensions |
|||
# Prevent the transcoder from modifying our meta hash |
|||
def initialize(file, options = {}, attachment = nil) |
|||
meta_value = attachment&.instance_read(:meta) |
|||
super |
|||
attachment&.instance_write(:meta, meta_value) |
|||
end |
|||
end |
|||
end |
|||
|
|||
Paperclip::Transcoder.prepend(Paperclip::TranscoderExtensions) |
Loading…
Reference in new issue