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Extract dominant colours from an image in Ruby using MiniMagick
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| def self.extract_dominant_colors(image_path, quantity=5, threshold=0.01) | |
| image = MiniMagick::Image.open(image_path) | |
| # Get image histogram | |
| result = image.run_command('convert', image_path, '-format', '%c', '-colors', quantity, '-depth', 8, 'histogram:info:') | |
| # Extract colors and frequencies from result | |
| frequencies = result.scan(/([0-9]+)\:/).flatten.map { |m| m.to_f } | |
| hex_values = result.scan(/(\#[0-9ABCDEF]{6,8})/).flatten | |
| total_frequencies = frequencies.reduce(:+).to_f | |
| # Create frequency/color pairs [frequency, hex], | |
| # sort by frequency, | |
| # ignore fully transparent colours | |
| # select items over frequency threshold (1% by default), | |
| # extract hex values, | |
| # return desired quantity | |
| frequencies | |
| .map.with_index { |f, i| [f / total_frequencies, hex_values[i]] } | |
| .sort { |r| r[0] } | |
| .reject { |r| r[1].end_with?('FF') } | |
| .select { |r| r[0] > threshold } | |
| .map { |r| r[1][0..6] } | |
| .slice(0, quantity) | |
| end |
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Shouldn't it reject values ending in
00instead ofFF?