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Versions: 10
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Stored size: 1.61 KB
Contents
# coding: utf-8
# frozen_string_literal: true
class PDF::Reader
module WidthCalculator
# Calculates the width of a glyph in a TrueType font
class TrueType
def initialize(font)
@font = font
if @font.font_descriptor
@missing_width = @font.font_descriptor.missing_width
else
@missing_width = 0
end
end
def glyph_width(code_point)
return 0 if code_point.nil? || code_point < 0
glyph_width_from_font(code_point) || glyph_width_from_descriptor(code_point) || 0
end
private
#TODO convert Type3 units 1000 units => 1 text space unit
def glyph_width_from_font(code_point)
return if @font.widths.nil? || @font.widths.count == 0
# in ruby a negative index is valid, and will go from the end of the array
# which is undesireable in this case.
if @font.first_char <= code_point
@font.widths.fetch(code_point - @font.first_char, @missing_width).to_f
else
@missing_width.to_f
end
end
def glyph_width_from_descriptor(code_point)
return unless @font.font_descriptor
# true type fonts will have most of their information contained
# with-in a program inside the font descriptor, however the widths
# may not be in standard PDF glyph widths (1000 units => 1 text space unit)
# so this width will need to be scaled
w = @font.font_descriptor.glyph_width(code_point)
if w
w.to_f * @font.font_descriptor.glyph_to_pdf_scale_factor
else
nil
end
end
end
end
end
Version data entries
10 entries across 9 versions & 2 rubygems