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Versions: 6
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Contents
# typed: true
# coding: utf-8
# frozen_string_literal: true
class PDF::Reader
# remove duplicates from a collection of TextRun objects. This can be helpful when a PDF
# uses slightly offset overlapping characters to achieve a fake 'bold' effect.
class OverlappingRunsFilter
# This should be between 0 and 1. If TextRun B obscures this much of TextRun A (and they
# have identical characters) then one will be discarded
OVERLAPPING_THRESHOLD = 0.5
def self.exclude_redundant_runs(runs)
sweep_line_status = Array.new
event_point_schedule = Array.new
to_exclude = []
runs.each do |run|
event_point_schedule << EventPoint.new(run.x, run)
event_point_schedule << EventPoint.new(run.endx, run)
end
event_point_schedule.sort! { |a,b| a.x <=> b.x }
event_point_schedule.each do |event_point|
run = event_point.run
if event_point.start?
if detect_intersection(sweep_line_status, event_point)
to_exclude << run
end
sweep_line_status.push(run)
else
sweep_line_status.delete(run)
end
end
runs - to_exclude
end
def self.detect_intersection(sweep_line_status, event_point)
sweep_line_status.each do |open_text_run|
if open_text_run.text == event_point.run.text &&
event_point.x >= open_text_run.x &&
event_point.x <= open_text_run.endx &&
open_text_run.intersection_area_percent(event_point.run) >= OVERLAPPING_THRESHOLD
return true
end
end
return false
end
end
# Utility class used to avoid modifying the underlying TextRun objects while we're
# looking for duplicates
class EventPoint
attr_reader :x
attr_reader :run
def initialize(x, run)
@x = x
@run = run
end
def start?
@x == @run.x
end
end
end
Version data entries
6 entries across 6 versions & 1 rubygems