From ba6a558a7088b811b63a90d20b82069eee7dfaa1 Mon Sep 17 00:00:00 2001 From: Claire Date: Sat, 29 Jun 2024 00:41:27 +0200 Subject: [PATCH] Simplify color extraction code using `bandunfold` (#30869) --- lib/paperclip/color_extractor.rb | 35 +++++++++++--------------------- 1 file changed, 12 insertions(+), 23 deletions(-) diff --git a/lib/paperclip/color_extractor.rb b/lib/paperclip/color_extractor.rb index 378af0961..fba32ba4c 100644 --- a/lib/paperclip/color_extractor.rb +++ b/lib/paperclip/color_extractor.rb @@ -116,34 +116,23 @@ module Paperclip # The number of occurrences of a color (r, g, b) is thus encoded in band `b` at pixel position `(r, g)` histogram = image.hist_find_ndim(bins: BINS) - # `histogram.max` returns an array of maxima with their pixel positions, but we don't know in which - # band they are + # With `bandunfold`, we get back to a (BINS*BINS)×BINS 2D image with a single band. + # The number of occurrences of a color (r, g, b) is thus encoded at pixel position `(r * BINS + b, g)` + histogram = histogram.bandunfold + _, colors = histogram.max(size: 10, out_array: true, x_array: true, y_array: true) - colors['out_array'].zip(colors['x_array'], colors['y_array']).map do |v, x, y| - rgb_from_xyv(histogram, x, y, v) - end.flatten.reverse.uniq + colors['x_array'].zip(colors['y_array']).map do |x, y| + rgb_from_hist_xy(x, y) + end.flatten.reverse end # rubocop:disable Naming/MethodParameterName - def rgb_from_xyv(image, x, y, v) - pixel = image.getpoint(x, y) - - # As we only have the first 2 dimensions for this maximum, we - # can't distinguish with different maxima with the same `r` and `g` - # values but different `b` values. - # - # Therefore, we return an array of maxima, which is always non-empty, - # but may contain multiple colors with the same values. - - pixel.filter_map.with_index do |pv, z| - next if pv != v - - r = (x + 0.5) * 256 / BINS - g = (y + 0.5) * 256 / BINS - b = (z + 0.5) * 256 / BINS - ColorDiff::Color::RGB.new(r, g, b) - end + def rgb_from_hist_xy(x, y) + r = ((x / BINS) + 0.5) * 256 / BINS + g = (y + 0.5) * 256 / BINS + b = ((x % BINS) + 0.5) * 256 / BINS + ColorDiff::Color::RGB.new(r, g, b) end def w3c_contrast(color1, color2)