diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/paperclip/color_extractor.rb | 189 | ||||
| -rw-r--r-- | lib/paperclip/image_extractor.rb | 2 | ||||
| -rw-r--r-- | lib/paperclip/transcoder_extensions.rb | 14 |
3 files changed, 204 insertions, 1 deletions
diff --git a/lib/paperclip/color_extractor.rb b/lib/paperclip/color_extractor.rb new file mode 100644 index 000000000..44fe5ff1d --- /dev/null +++ b/lib/paperclip/color_extractor.rb @@ -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 diff --git a/lib/paperclip/image_extractor.rb b/lib/paperclip/image_extractor.rb index f5a54d1a5..aab675a06 100644 --- a/lib/paperclip/image_extractor.rb +++ b/lib/paperclip/image_extractor.rb @@ -43,7 +43,7 @@ module Paperclip begin cli.run - rescue Cocaine::ExitStatusError + rescue Cocaine::ExitStatusError, ::Av::CommandError dst.close(true) return nil end diff --git a/lib/paperclip/transcoder_extensions.rb b/lib/paperclip/transcoder_extensions.rb new file mode 100644 index 000000000..c0b2447f3 --- /dev/null +++ b/lib/paperclip/transcoder_extensions.rb @@ -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) |